iPlants of the Nyika Plateau

Plants of the Nyika Plateau

ii Plants of the Nyika Plateau

Recommended citation formatBURROWS, J.E. & WILLIS, C.K. (eds) 2005. Plants of the Nyika Plateau: an account of the vegetation of the Nyika National Parks of Malawi and Zambia. Southern African Botanical Diversity Network Report No. 31. SABONET, Pretoria.

Produced and published bySouthern African Botanical Diversity Network (SABONET)c/o South African National Biodiversity Institute, Private Bag X101, 0001, Pretoria

Printed in 2005 in the Republic of South Africa by Capture Press, Pretoria, (27) 12 349-1802

ISBN 1-919976-08-6

© 2005 SABONET. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means without the permission of the copyright holder.

Editor-in-chief: Marthina MössmerSubeditors: Lidia Gibson & Hanlie van HeerdenIndexing: Marthina Mössmer & Martin Mössmer

Text design and layout: Antoinette BurkhardtCover design: Antoinette Burkhardt, Pretoria, South Africa (27) 83 6351446.Front cover: Top: Lake Kaulime (C. Willis). Bottom, left to right: Vittaria guineensis var. orientalis (J. Burrows); Disa ukingensis (H. Kurzweil); Delphinium leroyi (J. Burrows); Streptocarpus wittei (W. Pawek); Scadoxus multiflorus subsp. multiflorus (J. Burrows).Back cover: Impressions of Nyika (W. Pawek). Spine: Impatiens tinctoria subsp. latifolia (J. Burrows).

SABONET website: www.sabonet.org

This report is a product of the Southern African Botanical Diversity Network (SABONET) and was made possible through support provided by the Global Environment Facility (GEF)/United Nations Development Programme (UNDP) and the United States Agency for International Development (USAID)/World Conservation Union-Regional Office for southern Africa (IUCN ROSA) (Plot no. 14818 Lebatlane Road, Gaborone West, Extension 6 Gaborone, Botswana), under the terms of Grant No. 690-0283-A-00-5950. The opinions expressed herein are those of the authors and do not necessarily reflect the views of GEF/UNDP, USAID/IUCN ROSA, the SABONET Steering Committee or SABONET National Working Groups.

iiiPlants of the Nyika Plateau

Plants of the Nyika PlateauAn account of the vegetation of the Nyika National Parks

of Malawi and Zambia

Edited byJohn E. Burrows & Christopher K. Willis

2005

Southern African Botanical Diversity Network Report No. 31

viiPlants of the Nyika Plateau

Contents

Contributors .......................................................................................................................... viiiForeword ................................................................................................................................. ixPreface ..................................................................................................................................... xAbbreviations and acronyms ................................................................................................... xiHerbarium acronyms ............................................................................................................... xiAcknowledgements ............................................................................................................... xiii

Introduction .............................................................................................................................. 1 Climate ............................................................................................................................... 2 Drainage and soils .............................................................................................................. 3 Landslips ............................................................................................................................ 3 Fire ..................................................................................................................................... 4 Vegetation communities ..................................................................................................... 4 Plant diversity ..................................................................................................................... 9 Endemism ........................................................................................................................... 9Botanical exploration of the Nyika Plateau ............................................................................. 11

Species accounts .................................................................................................................... 19 Anthocerotophyta ............................................................................................................. 20 Hepatophyta ..................................................................................................................... 20 Bryophyta ......................................................................................................................... 21 Pteridophyta ..................................................................................................................... 25 Gymnosperms .................................................................................................................. 46 Dicotyledons .................................................................................................................... 48 Monocotyledons ............................................................................................................. 287

Glossary ............................................................................................................................... 369References and further reading ............................................................................................. 376Photo credits ........................................................................................................................ 382Collectors’ index .................................................................................................................. 383Index to common names ...................................................................................................... 384Index to scientific names ...................................................................................................... 387

viii Plants of the Nyika Plateau

ContributorsJohn BurrowsBuffelskloof Herbarium, LydenburgScientific editor and species treatments for all families, except those listed below.

Lyn FishNational Herbarium, South African National Biodiversity Institute, PretoriaPoaceae, Cyperaceae, Commelinaceae

Marinda KoekemoerNational Herbarium, South African National Biodiversity Institute, PretoriaAsteraceae, Bryophyta

Hubert KurzweilCompton Herbarium, South African National Biodiversity Institute, Cape TownOrchidaceae

Graham WilliamsonOrchidaceae

Christopher WillisSouth African National Biodiversity Institute, PretoriaIntroduction and Botanical Exploration

Pieter WinterNational Herbarium, South African National Biodiversity Institute, Pretoria (formerly of University of the North Herbarium, Polokwane)Acanthaceae, Apiaceae, Crassulaceae, Lamiaceae

IllustratorsSandie Burrows (principal illustrator)Charmaine BartmanAuriol Batten Eleanor Catherine Maureen Church Derek Erasmus Victoria Friis (Goaman) Christine Grey-Wilson Mary Grierson Pat HallidayCythna Letty Julia Loken John ManningWilma RouxClare Smith Margaret TebbsWilliam TrevithnickH. Wouda-du Toit Graham Williamson Heather Wood

xiPlants of the Nyika Plateau

Abbreviations and acronymsAETFAT Association pour l’Etude Taxonomique de la Flore d’Afrique Tropical (Association for the Taxonomic Study of the Flora of Tropical Africa)aff. affinis, affiliated to, bordering alt. altitudeauctt. auctorum, of authors, implying in common usageBP before presentC.A.R. Central African Republicca circa, about, roughlycf. confer, compare withcoll. collegit, he gathered, collected byCSIR Council for Scientific and Industrial ResearchCUSO Canadian University Service OverseasDel. Delineavit, drawn byD.R.C. Democratic Republic of Congo (formerly Zaire)E. east, eastern (in species lists)et al. et alii, and othersF.T.A. Flora of Tropical AfricaF.T.E.A. Flora of Tropical East AfricaF.Z. Flora zambesiacaGEF Global Environment Facilityholo. holotypeibid. ibidem, in the same placeiso. isotypeIUCN The World Conservation Union lecto. lectotypeloc.cit. loco citato, at the place cited, usually implying “cited above”LUOTC Leeds University Officer Training Corpsms. manuscriptN. north, northern (in species lists)nom. alt. nomen alternativum, an alternative namenom. cons. nomen conservandum, conserved namenom. illeg. nomen illegitimum, illegitimate namenom. nudum nomen nudum, name published without a descriptionS. south, southern (in species lists)s.n. sine numero, without a numberSABONET Southern African Botanical Diversity NetworkSAC Satellite Application Centresp. species, singularspp. species, pluralSUOTC Southampton University Officer Training Corpssyn. syntypeUNDP United Nations Development ProgrammeW. west, western (in species lists)WWF World Wide Fund for Nature

Herbarium acronymsHerbarium acronyms follow Holmgren, Holmgren & Barnett (1990) and Smith & Willis (1999).

A Herbarium, Arnold Arboretum, Harvard University, Cambridge, Massachusetts, U.S.A.

xii Plants of the Nyika Plateau

B Herbarium, Botanischer Garten und Botanisches Museum Berlin-Dahlem, Berlin, GermanyBM Herbarium, Botany Department, The Natural History Museum, London, England, U.K.BOL Bolus Herbarium, Botany Department, University of Cape Town, Cape Town, South AfricaBR Herbarium, Nationale Plantentuin van België, Jardin Botanique National de Belgique, Domein van Bouchout, Meise, BelgiumBRLU Herbarium, Laboratoire de Botanique Systématique et de Phytosociologie, Université Libre de Bruxelles, Bruxelles, BelgiumC Herbarium, Botanical Museum, University of Copenhagen, Copenhagen, DenmarkCAH Herbarium, Department of Biological Sciences, University of Zimbabwe, Harare, ZimbabweCOI Herbarium, Botanical Institute, University of Coimbra, Coimbra, PortugalDAV John M. Tucker Herbarium, Botany Department, University of California, Davis, California, U.S.A.DBN Herbarium, National Botanic Gardens, Glasnevin, Dublin, IrelandDSM Herbarium, Botany Department, University of Dar es Salaam, Dar es Salaam, TanzaniaE Herbarium, Royal Botanic Garden, Edinburgh, Scotland, U.K.EA Herbarium, National Museums of Kenya, Nairobi, KenyaFHO Daubeny Herbarium, Plant Sciences Department, University of Oxford, England, U.K.FRIM Forestry Research Institute of Malawi, Zomba, MalawiGA Herbarium, University of Georgia, Athens, Georgia, U.S.AJ Charles E. Moss Herbarium, Botany Department, University of the Witwatersrand, Johannesburg, South AfricaK Herbarium, Royal Botanic Gardens, Kew, England, U.K.LISC Herbário, Centro de Botânica, Instituto de Investigação Científica Tropical, Lisbon, PortugalLMA Herbarium, National Institute for Agronomic Research, Maputo, MozambiqueLMJ Herbarium, Botanical Department of the Cotton Research Centre, Maputo, Mozambique. LMJ transferred to LMA.M Herbarium, Botanische Staatssammlung, München, GermanyMA Herbario, Real Jardín Botánico, Madrid, SpainMAL National Herbarium, Zomba, MalawiMO Herbarium, Missouri Botanical Garden, Saint Louis, Missouri, U.S.A.MPR Herbarium, National Plant Genetic Resources Centre, Mount Makulu Central Research Station, Chilanga, ZambiaMU Herbarium, Botany Department, Miami University, Oxford, Ohio, U.S.A.NBG Compton Herbarium, South African National Biodiversity Institute, Cape Town, South AfricaNDO Herbarium, Division of Forest Research, Forestry Department, Kitwe, ZambiaNH KwaZulu-Natal Herbarium, South African National Biodiversity Institute, Durban, South AfricaNU Herbarium, Botany Department, University of KwaZulu-Natal, Pietermaritzburg, KwaZulu-Natal, South AfricaNY Herbarium, New York Botanical Garden, Bronx, New York, U.S.A.OXF Fielding-Druce Herbarium, Plant Sciences Department, University of Oxford, Oxford, England, U.K.P Herbier, Laboratoire de Phanérogamie, Muséum National d’Histoire Naturelle, Paris, FrancePRE National Herbarium, South African National Biodiversity Institute, Pretoria, South AfricaRNG Herbarium, Plant Science Laboratories, University of Reading, Whiteknights, Reading, Berkshire, England, U.K.S Herbarium, Botany Departments, Swedish Museum of Natural History, Stockholm, SwedenSAM South African Museum Herbarium, Cape Town, South Africa; maintained as a separate entity within the Compton Herbarium (NBG), South African National Biodiversity Institute, Cape Town, South AfricaSCHG Southern Cape Herbarium, George, South AfricaSRGH National Herbarium (and Botanic Garden), Causeway, Harare, ZimbabweUC University Herbarium, University of California, Berkeley, California, U.S.A.UMO Herbarium, Biological Sciences Division, University of Missouri, Columbia, Missouri, U.S.A. UNIN University of the North Herbarium, Polokwane, South AfricaUPS Botanical Museum (Fytoteket), Uppsala University, Uppsala, SwedenUS United States National Herbarium, Botany Department, Smithsonian Institution, Washington, D.C., U.S.A.UT Garrett Herbarium, Utah Museum of Natural History, University of Utah, Salt Lake City, Utah, U.S.A.UZL University of Zambia Herbarium, Lusaka, ZambiaWAG Herbarium Vadense, Department of Plant Taxonomy, Agricultural University, Wageningen, NetherlandsWU Herbarium, Institut für Botanik, Universität Wien, Wien, Austria

ixPlants of the Nyika Plateau

ForewordI feel very honoured to have been asked by Christopher Willis, chief organiser of the SABONET Nyika Plateau Expedition in 2000, to provide a foreword for Plants of the Nyika Plateau. This book will be a valuable reference work for biodiversity managers, plan-ners, academics, researchers, decision-makers, NGOs, and local communities.

The Nyika Plateau is a unique ecosystem for the survival of old plants and birth of new ones. Over millennia, the mixture of both old and new plant species has resulted in unique plant diversity, making the Nyika Plateau one of the world’s hotspots or important plant areas. A new visitor to Nyika is always greeted on the main plateau by the beauty of the rolling grasslands with dotted outcrops of varied forests, hills, and mountaintops. Of course to the tourist, this is just another place for recreation, while the local people regard the Nyika Plateau as a source of clean water and valuable non-timber products; but to the biologist, that beauty, both at species and habitat level, becomes a big attraction for scientific inquiry. Thus, the rich plant diversity of the Nyika Plateau has been a subject of research for botanists over the years, and the SABONET Nyika Plateau Expedition and its resultant publication are commendable developments that will improve our knowledge about the plants of the Nyika Plateau.

The SABONET Nyika Plateau Expedition was one of the main capacity-building activities of the SABONET project; a similar col-lecting expedition was undertaken to southern Mozambique in 2001. The expedition was notable since it was organised from within the sub-region, and was attended by 24 participants from six countries in southern and eastern Africa (Malawi: 7, Mozambique: 1, South Africa: 9, Zambia: 4, Zimbabwe: 2 and Tanzania: 1). The participation of both veteran and young botanists from the region enriched the expedition and made it unique. The collection of 3,343 plant specimens is a remarkable achievement. The description of one new species, many new plant distribution records, and the identification of several rare species are indications of the international botanical importance of the Nyika Plateau. I have no doubt that the Nyika Plateau provided a natural theatre and laboratory where veteran botanists such as Augustine Salubeni, Hassam Patel, Leonard Mwasumbi, John Burrows, and Patrick Phiri, amongst others, taught their young colleagues many aspects of field botany and plant taxonomy, including collection techniques, field identifications, character recognition of major plant groups, Nyika Plateau endemics, and rare plants. The great plant diversity of the Nyika Plateau must indeed have re-affirmed and demonstrated once again to the expedition members the concept of a “hotspot”. In addition, the Nyika Plateau must have shown the unique distribution patterns of some plants, such as the pencil cedar, whose disjunct southern distribution appears to end at the Plateau.

The botanical survey of many developing countries remains poor mainly owing to lack of financial resources for fieldwork. This insuf-ficient knowledge about the botany of our plants will impede the implementation of international obligations (such as the Convention on Biological Diversity, Wetland Convention—RAMSAR, and Millennium Development Goals) that aim to assist our governments to achieve sustainable development. However, for the ten southern African countries, the GEF/UNDP and USAID/IUCN ROSA funding of the SABONET project has meant enhancement of scientific and technical co-operation on plant diversity. In particular, building a team of experts from the region to collect, identify, document, and publish Plants of the Nyika Plateau shows that, given adequate funding, Africa has the human capacity to document every plant in our respective countries. Certainly, the Nyika Plateau team should not rest, but use the Nyika Plateau experience to penetrate and botanise other important under-collected habitats in our sub-region. They should form a long-lasting human network on which the region will rely for solving botanical and taxonomic problems at both the national and regional level.

Professor J.H. Seyani

General Manager & Chief Executive National Herbarium and Botanic Gardens of Malawi

Manyenjere Forest (Zambia)Kasyaula Forest (Malawi)

x Plants of the Nyika Plateau

Preface

For in order to care deeply about something important it is first necessary to know about it. So let us resume old-fashioned expeditions at a quickened pace, solicit money for permanent field stations, and expand the support of young scientists—call them “naturalists” with pride—who by inclination and the impress of early experience

commit themselves to deep knowledge of particular groups of organisms.

—E.O. Wilson, “On the future of conservation biology”

This book represents our current knowledge and understanding of the diversity of plants found on the Nyika Plateau, and draws on both published and unpublished information. The checklist was started in 1999, to aid plant collectors on a SABONET-funded regional plant collecting expedition to the Nyika Plateau in March–April 2000; subsequently, the list has been refined, based on the collections made during the expedition.

One of our main aims was to make the final publication as useful to as broad an audience as possible. It had to be ac-cessible, not only to taxonomists and plant diversity specialists, but also to research staff working in the Nyika National Parks and tourists interested in the Nyika Plateau’s plant diversity. To this end, an illustration of every plant genus in the list has been included, making the task of identification easier. Where possible, diagnostic characters of specific genera have been indicated in the drawings. Photographs of landscapes and plants will assist readers in recognising some of the Nyika Plateau’s diverse landscapes, habitats, and flowering plants.

We believe that this publication will make a significant contribution towards documenting the Nyika Plateau’s diverse floral heritage. It is a continuation of work done by botanists and plant collectors, some more than a century ago. We recognise that this checklist may be incomplete, and trust that it will be expanded and improved upon as knowledge of the Nyika Plateau flora increases. Furthermore, it is our hope that this checklist will be used to assist conservation authorities and planners in safeguarding the Nyika Plateau’s flora and its associated life forms for both present and future generations.

John Burrows

Christopher Willis

Nkhonjera Hill

xiiiPlants of the Nyika Plateau

AcknowledgementsThis publication would not have been possible without the tremendous efforts of the SABONET publication and editorial team—Marthina Mössmer, Lidia Gibson, Hanlie van Heerden, and Antoinette Burkhardt. We thank them sincerely for their patience and professional approach towards the compilation of this book.

Sandie Burrows prepared the majority of the line drawings. The many hours spent illustrating the various Nyika plant genera are greatly appreciated. We also thank Sandie for her help and support during the SABONET Nyika Expedition in March–April 2000.

Generous financial support and sponsorship from the GEF/UNDP-funded Southern African Botanical Diversity Network (SAB-ONET) Project made this book possible. We thank the Chairman (Prof. Brian Huntley) and members of the SABONET Steering Committee, particularly Patrick Phiri, Dickson Kamundi, and Au-gustine Chikuni, for their ongoing support of and enthusiasm for the Nyika expedition and the development of this publication.

Co-funding from the Wildlife Conservation Society in Tanzania facilitated the participation of Leonard Mwasumbi from the University of Dar-es-Salaam in the Expedition.

We are grateful to the members of the SABONET Secretariat for their administrative and logistical support that made both the Expedition and the book possible: Stefan Siebert, Yolande Steenkamp, Nyasha Rukazhanga-Leboho (née Rukazhanga-Noko), Carina Haasbroek, Lorna Davis, and Elsabe Malan.

Thank you also to Leanna Els (South African National Biodiversity Institute, Pretoria) for administrative assistance.

Prior to the regional expedition the Royal Geographical Society’s Expedition Advisory Centre (London, U.K.) provided valuable advice, literature, and support.

We would specifically like to thank members of the SABONET Nyika Expedition for their tremendous enthusiasm and efforts in the field, and also for processing their specimens after the Expe-dition. Malawi: Humphrey Chapama (87 specimens), Augustine Chikuni (24), Crispin Kasakula (72), Montfort Mwanyambo (102), Hassam Patel (72), Augustine Salubeni (91), and Moffat Thera (115); Mozambique: Samira Izidine (142); Zambia: Patrick Phiri (548), Ashed Makukula (136), Annaniah Sakala (101), and Wilfred Moonga (135); South Africa: Sandie Burrows (214, with John Burrows), Lyn Fish (204), Marinda Koekemoer (244), Solomon Nkoana (110), Hubert Kurzweil (81), Christopher Willis (255), Pieter Winter (254), and Steve Johnson (no plant specimens collected); Zimbabwe: Alfred Maroyi (94) and Ratidzayi Takawira (155); Tanzania: Leonard Mwasumbi (107).

Many taxonomic specialists assisted in the identification of speci-mens from the Expedition. The following individuals are thanked for coordinating the completion of various family treatments listed in this checklist. Lyn Fish (PRE) provided the Poaceae, Cyperaceae, and Commelinaceae; Marinda Koekemoer (PRE) provided the Asteraceae and Bryophyta; Hubert Kurzweil (NBG) and Graham Williamson provided the Orchidaceae, and Pieter Winter (PRE, previously at UNIN) provided the treatments of the families Acanthaceae, Apiaceae, Crassulaceae, and Lamiaceae. We also acknowledge the following taxonomists who provided valuable taxonomic advice and support in the treatment of various plant groups: René Glen (PRE; aquatics), David Goyder (Kew; Apocy-

naceae), Robert Faden (Botany Department, Smithsonian Insti-tution, Washington DC, U.S.A.; Commelinaceae), Clare Archer (PRE; Cyperaceae), Robert Archer (PRE; Celastraceae), Marie Jordaan (PRE; Celastraceae), Serena Marner (OXF; Faurea), Kevin Balkwill (Botany Department, University of Witwatersrand; Acanthaceae), Diane Bridson (Kew; Rubiaceae), Henk Beentje (Kew; Helichrysum), Tom Cope (Kew; Poaceae), Yvette Harvey (Kew; Leonotis), Roger Polhill (Loranthaceae), and Alan Paton (Kew; Lamiaceae). Janice Golding assisted with the compilation of the section on the endemic plants of the Nyika Plateau.

We acknowledge the following people for use of their slides and images: Hubert Kurzweil, Serena Marner, Alan Paton, Mike Meadows, Hugh Synge, Graham Williamson, Bryan Simon, Bruce Hargreaves, Roger Polhill, Dick Brummitt, William and Jean Pawek, Gerald Pope, David Goyder, Isobyl la Croix, Audrey Moriarty, Bob and Françoise Dowsett-Lemaire, Norman Robson, and Jim Chapman.

Hassam Patel (Malawi) provided determinations for the specimens collected by Samira Izidine (Mozambique) on the Expedition. Hassam visited the LMA Herbarium (Maputo, Mozambique) from 12–20 November 2001 through an internship supported by the SABONET Project.

We thank Peter and Marianne Overton of Biosearch Nyika for their cooperation and the use of their plant checklists compiled over several years of collecting expeditions to various parts of the Nyika National Park.

We are grateful to Dick Brummitt (with Gerald Pope) for providing the section on Alexander Whyte’s travels, as well as the locality information of Adiantum reniforme in the Wovwe River, Nyika National Park. This enabled the Expedition team to collect the plant 28 years after it was first discovered and collected by the Wye College (University of London) Expedition in 1972. Hugh Synge kindly supplied us with a copy of the final report from the Wye College 1972 Malawi Project.

The Nyika and Malawi National Parks staff, particularly Gibson Mphepo, Muteto Dlamini, Paul Chisambo, and Jonas Luhanga offered support, companionship, and advice during the regional collecting expedition.

Thanks to Kit Cottrell (Entomology Department, Kutsaga Re-search Station, Harare, Zimbabwe) for earlier discussions and enthusiastic support for the SABONET Nyika Expedition.Ian Thomson, of the Nyika Vwaza Conservation Project, northern Malawi, gave advice and suggestions prior to the Expedition.

Alan Paton (Royal Botanic Gardens, Kew) obtained addresses and contact details of artists who contributed to published volumes of Flora zambesiaca. The Flora zambesiaca Management Com-mittee generously provided a complete set of Flora zambesiaca volumes to the SABONET Secretariat for use as reference mate-rial during the Expedition and for subsequent expeditions and training courses.

Estelle Potgieter and Anne-Lise Fourie of the Mary Gunn Library, National Herbarium, Pretoria, tracked down various publications and reference materials used in this book. Emsie du Plessis, of the South African National Biodiversity Institute’s Publications Section in Pretoria, edited earlier versions of the References sec-tion.

xiv Plants of the Nyika Plateau

Hugh Glen and Gerrit Germishuizen (PRE) provided assistance with notes and photographs of early plant collectors on the Nyika Plateau. Photographs of early collectors on the Nyika Plateau were also received from the Royal Botanic Gardens, Kew (Kate Pickard and James Kay), and the Hunt Institute for Botanical Documentation, Carnegie Mellon University, Pittsburgh, U.S.A. (Angela Todd and Lisa Ferrugia).

Rodney Moffett brought to our attention some infelicities in the species list.

John Nkhoma (Regional Geologist, Mzuzu, Malawi) furnished us with geological maps of the Nyika Plateau during our reconnais-sance expedition (May 1999) to the Nyika National Park.

The personnel of the Nyika Safari Company, particularly David and Robyn Foot, and Gary and Fiona Brown, are thanked for their warm hospitality and support at Chelinda Camp, Nyika National Park, during both the reconnaissance and the main expedition.

The satellite (LANDSATTM) image-map of the Nyika Plateau, dated 18 September 1995, was generated by the Division of Water, Forest, and Environment, CSIR, Pretoria, having been sourced from the CSIR’s Satellite Application Centre (SAC) data archives, South Africa. We thank Mark Thompson (Geospace International, Pretoria, South Africa) for his assistance in preparing this map and its interpretation.

We thank the following artists for allowing us to use their illustra-tions—first published in Flora zambesiaca and Flora of Tropical East Africa—free of charge: Auriol Batten, Maureen Church, Derek Erasmus, Victoria Friis (Goaman), John Manning, Julia Loken, Mary Grierson, Christine Grey-Wilson, Eleanor Cather-

Rainbow on Nyika.

ine, Margaret Tebbs, Pat Halliday, and Heather Wood. Graham Williamson gave us permission to use his illustrations of orchid genera, many drawn from specimens he collected on the Nyika Plateau.

We also thank personnel from Malawi’s National Herbarium (MAL), Zambia’s University of Zambia Herbarium (UZL), Mozambique’s herbarium (LMA) attached to the National Insti-tute of Agronomic Research, Zimbabwe’s National Herbarium (SRGH), South Africa’s National Herbarium (PRE), and Compton Herbarium (NBG) for their determinations of the Expedition specimens and for sharing duplicate specimens with other herbaria within southern Africa.

Antoinette Burkhardt prepared the maps of the Nyika National Park.

We thank Elmar Robbrecht and Jan Rammeloo (BR) for their support in accessing Nyika-related information (specimens, pho-tographs, and species lists) from the herbarium attached to the National Botanic Garden, Brussels, Belgium.

In order to study Nyika specimens housed in herbaria in the U.K., C.K. Willis was supported through a SABONET internship for a study visit to the BM, K, FHO, and OXF herbaria in May 2003. Many researchers at these institutions offered assistance and useful discussions concerning the plants and botanical collectors of the Nyika Plateau: Richard Bateman and Roy Vickery (BM), Simon Owens, Dick Brummitt, Kate Pickard, James Kay, Brian Schrire, David Goyder, Gerald Pope, Henk Beentje, Kaj Vollesen, Alan Paton (K), Hugh Synge, Peter Overton, Stephen Harris, Alison Strugnell (FHO), and Serena Marner (OXF).

1Plants of the Nyika Plateau

Introduction

Where essential silence cheers and blesses,And forever in the hill-recesses

Her more lovely musicBroods and dies.

O to dream, O to awake and wanderThere, and with delight to take and render,

Through the trance of silence,Quiet breath;

Lo! for there, among the flowers and grasses,Only the mightier movement sounds and passes;

Only winds and rivers,Life and Death.

—R.L. Stevenson

The Nyika Plateau—the largest montane complex in south- central Africa—lies close to the northern tip of Lake Malawi. Most

of the Plateau lies in Malawi, with a small section across the border in Zambia. The name “Nyika” means wilderness, and the

Plateau consists of rolling grasslands, criss-crossed by deep valleys, with occasional forest patches.

2 Plants of the Nyika Plateau

Burchell’s zebra

Nthakati Peak

Acacia abyssinica

The Nyika Plateau separates two of the major faults of the African Rift Valley system—Lake Malawi to the east and the Luangwa Valley of Zambia to the west. Nyika’s position along the Rift Valley

system results in frequent earth tremors, and northern Malawi is, indeed, the most seismically active part of the country (Johnson 1993).

The Nyika Plateau occupies an area of some 1,800 km2 above the 1,800 m contour, which usually marks the zone of transition from woodland to montane grassland and forest. Of the total area, only about 70 km2 on the western side is within Zambia (Dowsett-Lemaire 1985). The Plateau, roughly oval in shape and oriented in a northeasterly direction, lies between 10O15’–10O50’S and 33O35’–34O05’E. Only the wet eastern escarpment is extensively forested. Between 2,100 m and 2,500 m, the central plateau (approximately 60% of the montane area) consists of rolling Loudetia—Andropogon grassland, interspersed with small patches of low forest. These forest patches account for less than three percent of the area (Dowsett-Lemaire 1985).

The surface of the Plateau is gently undulating, with convex valley sides sloping at 10O to 15O. Towards the margins though, slopes are steeper, particularly in the north and east (Meadows 1984a). At times, the valleys that cut into the surface are up to 1 km wide, and 200 m deep. Usually, such valleys are partially filled with a variety of sediments (the maximum recorded depth being 6.2 m) (Meadows 1984a) and have poorly drained marshy floors. Occasionally, large high granite or resistant quartzite outcrops rise above the grassland.

Most of the remote Nyika Plateau is included within Malawi’s Nyika National Park; originally called Malawi National Park, the name of the park was changed to the Nyika National Park in 1969. It is the largest of Malawi’s national parks and is currently administrated by the Department of National Parks and Wildlife. In 1978 the Nyika National Park area was extended from the initial 940 km2 to its current size and includes all of the plateau escarpments and most of the northeast and south hill zones (Johnson 1993). The park now spans 3,134 km2, with another 70 km2 on the western edge of the Nyika Plateau belonging to the Zambian Nyika National Park.

The highest points on the Nyika Plateau are Nganda Hill at 2,607 m in the north, and Kasaramba at 2,460 m in the southeast. The lowest point drops to 580 m in the northeast corner of the park along the Ruwile River (Johnson 1993). Lake Kaulime near Chelinda is the only natural lake in the park–it was formed by a landslide that blocked the outflow from one of the headwaters of the North Rukuru River (Johnson 1993).

Climate

Malawi has a single rainy season during the summer months of November to April (Dowsett-Lemaire 1985). Minimum monthly temperatures at Chelinda (2,300 m), Nyika National Park, vary between 11OC (June–July) and 16OC (November–December) (Dowsett-Lemaire 1985). A record min-imum temperature of -12OC has been measured at Chelinda (G. Brown, pers. comm.). Maximum temperatures are relatively stable throughout the year and vary between 17OC and 20OC. Temperatures of up to 26 OC are recorded during September–November and February.

3Plants of the Nyika Plateau

The high-rainfall areas (with an annual mean above 1,500 mm) are located on the eastern and western sides of the Nyika Plateau. Much of the high plateau above 2,200 m experiences a lower rainfall, usually averaging 1,000–1,200 mm per annum. The figures are even lower in the north, in the shadow of the high peaks of Nganda and Domwe (Dowsett-Lemaire 1985). According to Cater (1993), most of the rain comes from the west, even though the prevailing wind throughout the year is easterly. Mist-belt conditions (known locally as chiperone) do not occur frequently in summer, but from June to September the eastern half of the plateau is often covered with cloud down to ground level (Cater 1993).

Drainage and soils

There are four major rivers that have their source in the headwater dam-bos of the Nyika Plateau—the North Rukuru, North Rumphi, Chelinda-Rumphi, and the Runyina, all draining into Lake Malawi. These rivers are of great importance to water management in the Northern Region of Malawi, as water supply to much of this area would be totally cut off should the dambos ever dry up (Meadows 1984a). Spectacular rapids and waterfalls, such as the Chisanga Falls, are formed where rivers cut through the rim of the Plateau.

The soils of the plateau are mainly acidic with a pH ranging from 4.0 to 5.5 (Williamson 1979). These humic latosols are typical of the high-plateau soils of the tropics (Meadows 1984a).

Landslips

There are many landslip scars on the Nyika Plateau, some relatively fresh and others older and revegetated. While earth tremors can be responsible for mass movement on a large scale and are known to occur on the Nyika Plateau, heavy rainfall is probably the main cause (Meadows 1984a). The landslips are concentrated in the eastern part of the plateau, a fact that suggests greater precipitation (or perhaps greater precipitation intensities) and consequently greater chemical weathering (Meadows 1984a). Geol-ogy may also affect landslip distribution, as Cordierite Gneiss is restricted to the eastern plateau (Thatcher 1974, Meadows 1984a). Some of these landslips are large, like the Chelinda 1960 event, but many are small and typically characterised by a pronounced concavity in the hillside and a hummocky topography lower down (Meadows 1984a).

According to Meadows (1984a), landslips seem to be important in determining the vegetation pattern on the Nyika Plateau. Many of the forest patches are associated with the valley heads on the steeper slopes of the concavities, of which many are former landslip scars. Three factors favour the survival of the forest species in these scars:• In the initial post-movement period, much open ground is made avail-

able for the establishment of tree species since the broken topography and bare soil act as a firebreak.

• The steeper slopes on which these forests are concentrated are not favourable to fire spreading, since fires tend to travel up, rather than down, steep inclines. Fire is unlikely to travel up these slopes from lower down, because the dambos, which consistently lie below the forests, are saturated even in the dry season and could therefore not be the source of fires.

Nganda Peak

Chisanga Falls

Roan antelope

4 Plants of the Nyika Plateau

Table 2. The 21 largest genera on the Nyika Plateau. Genus Family Species

Habenaria Orchidaceae 43

Vernonia Asteraceae 31

Plectranthus Lamiaceae 26

Crotalaria Fabaceae 25

Disa Orchidaceae 22

Helichrysum Asteraceae 21

Indigofera Fabaceae 21

Satyrium Orchidaceae 20

Eulophia Orchidaceae 18

Eragrostis Poaceae 16

Panicum Poaceae 16

Aeschynomene Fabaceae 15

Hyparrhenia Poaceae 14

Eriosema Fabaceae 14

Cyperus Cyperaceae 14

Scleria Cyperaceae 14

Buchnera Scrophulariaceae 13

Sporobolus Poaceae 12

Bidens Asteraceae 11

Rhynchosia Fabaceae 11

Polygala Polygalaceae 11

Table 1. Breakdown of plant taxa on the Nyika Plateau. Families Genera Species Infra- Exotic specific species

taxa

Pteridophytes 22 47 107 2 0

Gymnosperms 3 4 4 0 1

Monocotyledons 24 147 548 10 2

Dicotyledons 111 486 1,158 36 23

Totals 160 684 1,817 48 26

• The soils that ultimately develop under the forest vegetation are deep and are a much better medium for plant growth, with greater moisture capacities that discourage fire (Meadows 1984a).

Fire

Fire, nevertheless, plays an important role on the Plateau. Each hectare of plateau grassland is burned approximately every three years as stipulated by National Park policy. Management goes to considerable lengths to ensure that these fires do not destroy the forest patches and an elaborate system of fire-breaks has been constructed around the larger patches (Meadows 1984a). Lemon (1968) could find no evidence that the induced Nyika fires cause destruction of valuable forage plants and invasion by weeds, although there is a drain on the nutrient reserves. Indeed, the welfare of many species, particularly some legumes, such as Aeschynomene oligophylla, may well depend on periodic burning (Meadows 1984a).

Plateau grassland is burned for two reasons. Firstly, controlled burns and fire-breaks initiated in the early part of the dry season ensure that the damaging hot burns later during the dry season do not happen. Secondly, burning appears to encourage game animals. Herds of bushbuck, zebra, eland, and roan antelope selectively graze the more recently-burnt ground, presumably because the fresh shoots that emerge after burning are more nutritious (Meadows 1984a).

Vegetation communities

Within the Nyika National Park, miombo woodland covers roughly 60% of the park, montane grasslands and dambos around 37%, and evergreen forest more or less 3% (Johnson 1993). Four main vegetation communities are recognised and are described in more detail below.

Vitumbi Road

Table 3. A comparison between the largest families on the Nyika Plateau and Mt. Mulanje,* Malawi. Nyika Plateau No. of Mt. Mulanje No. of (total taxa: 1,891) species (total taxa: 1,317) species Orchidaceae 200 Orchidaceae 122

Asteraceae 185 Asteraceae 99

Poaceae 165 Poaceae 90

Fabaceae (sensu stricto) 159 Fabaceae (sensu stricto) 82

Rubiaceae 90 Rubiaceae 82

Cyperaceae 73 Euphorbiaceae 46

Lamiaceae 65 Cyperaceae 37

Euphorbiaceae 41 Lamiaceae 35

Apocynaceae (sensu lato) 41 Acanthaceae 31

Acanthaceae 33 Scrophulariaceae 20

Scrophulariaceae 33

* A. Strugnell, pers. comm. (2003).

5Plants of the Nyika Plateau

Table 2. The 21 largest genera on the Nyika Plateau. Genus Family Species

Habenaria Orchidaceae 43

Vernonia Asteraceae 31

Plectranthus Lamiaceae 26

Crotalaria Fabaceae 25

Disa Orchidaceae 22

Helichrysum Asteraceae 21

Indigofera Fabaceae 21

Satyrium Orchidaceae 20

Eulophia Orchidaceae 18

Eragrostis Poaceae 16

Panicum Poaceae 16

Aeschynomene Fabaceae 15

Hyparrhenia Poaceae 14

Eriosema Fabaceae 14

Cyperus Cyperaceae 14

Scleria Cyperaceae 14

Buchnera Scrophulariaceae 13

Sporobolus Poaceae 12

Bidens Asteraceae 11

Rhynchosia Fabaceae 11

Polygala Polygalaceae 11

Table 4. A summary of the 33 Nyika endemics. Taxon Life form Habitat niche Notes

Acanthaceae

Monechma varians C.B.Clarke Suffrutex herb Habitat unknown Only three collections.

Apiaceae

Peucedanum articulatum C.C.Townsend Perennial herb Wet montane grassland Occasional.

Peucedanum sp. nov., Perennial herb Montane grassland in wet areas Occasional.

aff. P. harmsianum H.Wolff

Pimpinella nyassica Norman Geophytic herb Streamsides in montane grassland Occasional.

Apocynaceae

Ceropegia sp. [Goyder, Paton & Suffrutex herb Shallow soil over rock Only one collection.

Tawakali 3579 herbarium?]

Glossostelma nyikense Goyder Suffrutex herb Montane grassaland From six collections.

Asteraceae

Brachythrix malawiensis (Wild & G.V.Pope) Perennial herb Montane grassland or woodland Only Nyika-Malawi, from two

G.V.Pope localities.

Brachythrix pawekiae Wild & G.V.Pope Perennial herb Montane grassland Few collections only.

Brachythrix sonchiodes Wild & G.V.Pope Perennial herb Secondary forest or marshes/ Also Nyika-Zambia. Possibly

streamsides widespread.

Helichrysum hilliardiae Wild Perennial herb Swamps or marshes in montane Unspecified locality on Nyika

grassland Zambia. Several collections on Nyika-Malawi. Locally common.

Helichrysum tithoniodes Wild Perennial herb Miombo woodland Only Nyika-Malawi. Locally

common.

Osteospermum nyikensis Wild Perennial herb Montane grassland Two records only.

Vernonia fractiflexa Wild Perennial herb Montane grassland Type locality only (near

Nganda Peak).

Vernonia kawoziensis F.G.Davies Perennial herb Miombo woodland Type locality only

(Kawozya Hill).

Balsaminaceae

Impatiens rubromaculata Warb. subsp. Perennial herb Moist forest Taxonomy uncertain.

schulziana (Launert) Grey-Wilson

Crassulaceae

Crassula nyikensis Baker f. Succulent shrub Bare rock Only three collections.

Euphorbicaeae

Phyllanthus nyikae Radcl.-Sm. Perennial shrub Montane grassland at forest margins Mainly eastern Nyika-Malawi. Perhaps only two collections. Rare.

Fabaceae

Indigofera hilaris Eckl. & Zeyh. var. Suffrutex shrub Montane grassland Nyika-Malawi only. Rare.

microscypha (Baker) Gillett

Kotschya africana Endl. var. latifoliola Verdc. Perennial shrub Rocky slopes & seepage areas Occasional. Nyika-Zambia only.

fringing evergreen forests

Crotalaria pilosiflora Baker Perennial herb Miombo woodland Probably widely distributed. Rare.

Lamiaceae

Plectranthus acaulis Brummitt & Seyani Suffrutex herb Montane grassland A number of collections.

Frequent.

Plectranthus zebrarum Brummitt & Seyani Suffrutex herb Montane grassland A number of collections.

Frequent.

Lobeliaceae

Cyphia nyikensis Thulin Herb (?) Shallow soil over rock Only one collection.

Orchidaceae

Cynorkis anacamptoides Kraenzl. Geophytic herb Wet & marshy grassland Few collections only (possibly

var. ecalcarata P.J.Cribb two).

Table 3. A comparison between the largest families on the Nyika Plateau and Mt. Mulanje,* Malawi. Nyika Plateau No. of Mt. Mulanje No. of (total taxa: 1,891) species (total taxa: 1,317) species Orchidaceae 200 Orchidaceae 122

Asteraceae 185 Asteraceae 99

Poaceae 165 Poaceae 90

Fabaceae (sensu stricto) 159 Fabaceae (sensu stricto) 82

Rubiaceae 90 Rubiaceae 82

Cyperaceae 73 Euphorbiaceae 46

Lamiaceae 65 Cyperaceae 37

Euphorbiaceae 41 Lamiaceae 35

Apocynaceae (sensu lato) 41 Acanthaceae 31

Acanthaceae 33 Scrophulariaceae 20

Scrophulariaceae 33

* A. Strugnell, pers. comm. (2003).

6 Plants of the Nyika Plateau

Table 4. A summary of the 33 Nyika endemics. (cont.) Taxon Life form Habitat niche Notes

Disa praecox (H.P.Linder) H.P.Linder Geophytic herb Montane grassland A number of collections.

(= Herschelianthe praecox ) Occasional.

Disperis bifida P.J.Cribb Geophytic herb Forest floors Limited distribution. Nyika-

Zambia only.

Disperis breviloba Verdc. Geophytic herb Miombo woodland & montane

grassland

Habenaria livingstoniana la Croix & P.J.Cribb Geophytic herb Miombo woodland Type locality only. Eastern

escarpment. Rare.

Habenaria riparia Renz & Grosvenor Geophytic herb Swampy areas & streamsides Type locality only. Frequent.

Stolzia compacta P.J.Cribb subsp. compacta Epiphytic herb Montane forest Single collection. Locally

common.

Oxalidaceae

Oxalis chapmaniae Exell Geophytic herb Montane grassland Frequent.

Poaceae

Setaria grandis Stapf Perennial herb Drainage lines & forest margins Frequent.

Polygalaceae

Polygala lactiflora Paiva & Brummitt Perennial shrub Montane scrub Occasional. Table 5. A summary of the 13 near-endemics of the Nyika Plateau. (A near-endemic is defined here as a species oc-curring mainly on the Nyika but also found on the Viphya Plateau, Makutu Mountains, Mafinga Mountains and/or the Misuku Hills.) Acanthaceae

Isoglossa strigulosa C.B.Clarke

Euphorbiaceae

Erythrococca trichogyne (Müll.Arg.) Prain var. psilogyne Radcl.-Sm.

Euphorbia ampliphylla Pax

Fabaceae

Aeschynomene tenuirama Baker var. hebecarpa Verdc.

Vigna phoenix Brummitt

Lamiaceae

Ocimum obovatum E.Mey. ex Benth. subsp. crystallinum (A.J.Paton) A.J.Paton

Orchidaceae

Habenaria nyikensis G.Will.

Habenaria petraea Renz & Grosvenor

Habenaria pubidens P.J.Cribb

Polygalaceae

Polygala nyikense Exell

Scrophulariaceae

Buchnera crassifolia Engl.

Buchnera nitida Skan

Selaginaceae

Selago thyrsoidea Baker var. thyrsoidea

Chelinda Bridge

Lake Kaulime

View looking south-westwards towards Mwanda Mountain forming the western edge of the Nyika Plateau.

7Plants of the Nyika Plateau

Table 6. Comparison of the floristic richness and endemism of similar upland areas within the Afromontane archipelago. Nyika Plateau, Mount Mulanje, Chimanimani Mts, Simien Highlands, Mt Cameroon, Malawi Malawi1 Zimbabwe2 Ethiopia3 Cameroon4 Area (km2) 3,204 640 390 ? 2,700

Taxa/km2 0.59 2.03 2.2 ? 0.9

Number of total taxa 1,8915 (1,7826) 1,3035,6 859 550 2,4355 (2,2486)

Number of endemics 33 69 707 (418) 12 49

Percentage endemism 1.7% 5.3%6 8.1% (4.8%) 2.2% 2.0%

Number of near-endemics 13 25 ? ? ?

References:

1. Strugnell (2002)

2. Wild (1964), Mapaura (2002)

3. Puff & Nemomissa (2001)

4. Cable & Cheek (1998)

Gently undulating landscape of grasslands and forests on the Nyika Plateau.

Notes:

5. Includes subspecific taxa and naturalised exotic species.

6. Excludes pteridophytes.

7. After Mapaura (2002).

8. After Wild (1964).

Dambo feeding into the Dembo River, a tributary of the North Rumphi River.

Lobelia mildbraedii (Lobeliaceae) growing on the edge of Lake Kaulime, Nyika National Park.