PLANT ID

TaxonomyCredits:

All photos from “Desert Ecology of Tucson, AZ” by Brad Fiero, PCC

Important Plant Families in the Sonoran Desert Cactaceae--Cacti

Fabaceae—Palo verdes, mesquites

Agavaceae—Agaves, yuccas

Fabaceae (Legumes)

Legume or pea family

Includes Trees:

Mesquites Shrubs:

Dalea Wildflowers:

Senna

Leaves Main role is

photosynthesis (food for plant)

Three leaf parts: Blade Petiole Expanded leaf

basePicture from Desert Ecology of

Tucson, AZ by Brad Fiero

Blade structure Simple:

Blade is simple Compound:

Blade is divided into leaflets

Types of compound leaves Palmately compound: leaflets

radiate from a common point; like fingers from the palm of a hand

Types of compound leaves

Pinnately compound: Just primary

leaflets Bipinnately

compound: Primary and

secondary leaflets

Fabaceae (Legumes) Common features

Pea-like flowers & pods Pinnate & bipinnate

compound leaves Fertilize soil

Add nitrogen to the soil by mutualistic relationship bacteria in root nodules

Act as nurse plants Trees provide wood &

shelter

Agavaceae Agaves, yuccas, etc. Evergreen leaf succulents with

sharp-pointed leaves arranged in a rosette around a very short stem

Provide food, shelter and alcohol

Agavaceae

Agaves: 12 species in AZ Most flower once in a

lifetime between 10 & 30 years of age

Pollinated by bats

Agavaceae Yuccas

Flower annually (most in May)

Mostly pollinated by Yucca Moth

Cacti are endemic to the Americas All are succulents (but not all

succulents are cacti)

Cactaceae

Cact-eristics

Areoles – place where spines, branches, and flowers come from

Petals and Sepals intergrade with each other

Flowers have many stamens Flowers have multi-lobed stigma Most use CAM photosynthesis

Cact-eristics

Cact-eristics 6 major cactus groups

Columnar Barrel Hedgehog Pincushion Cholla Prickly Pear

Cact-eristics Columnar

Cylindrical stems Pleats run from bottom to top

10 times taller than wide

Barrel Cylindrical stems Pleats run from bottom to top

Less than 10 times taller than wide Flowers from top of stem

Cact-eristics Hedgehog

Cylindrical stems Pleats run from

bottom to top Less than 10 times

taller than wide Diameter less than 5”

and less than 12” tall Flowers from side of

stems Spines not hooked

Cact-eristics Pincushion

Unbranched cylindrical stems

Don’t have pleats Species in Sonoran

Desert less than 6” tall

Central spines from areole often hooked

Opuntia

Cholla Branched

cylindrical stems with jointed segments

Prickly Pear Have flattened,

pad-like stems with jointed segments

Opuntia

Seeds have tan covering instead of shiny black of other cacti

Catclaw Acacia

•Grey or brown scaly bark

•Leaves compound bipinnate

•Curved, sharp spines

•Pale yellow flowers in late spring

•Make a tea from roots for stomach and kidney problems

Whitethorn Acacia

• Bipinnate compound leaves

• White spines on young branches, none on old branches

• Fragrant bright yellow flowers

Desert Ironwood

• Up to 35’ tall

• Gray bark, lots of cracks. Wood chocolate brown

• Pinnate compound leaves

• Sensitive to frost – found almost only in Sonoran Desert

• Dense wood that sinks in water

•Grows extremely slowly

Velvet Mesquite

•Bipinnate compound leaves

• Pods start green turn yellowish-brown

• Deepest taproot – up t o160’

• To germinate, passes through animal gut, or needs several years of weathering

• Important food source

Foothills Palo Verde • Yellowish-green smooth bark

• Allows tree to drop leaves in drought (drought deciduous) and can photosynthesize with its bark

• Bipinnate compound leaves

• Branches ends in a thorn, but no spine beneath leaves like in Blue Palo Verde

• Largest petal in 5-petaled flower is white

Blue Palo Verde•Yellowish-green smooth bark

• Small, straight spines hidden under leaves

• Leaves bipinnately compound with three or fewer secondary leaflets per primary leaflet (vs. four or more in Foothills Palo Verde)

• Flowers in spring before Foothills Palo Verde

Saguaro (Ha:san)

• May live over 200 years and reach 75’

• Begin to flower at about 50 years old and branch between 50 and 100 years

• Branches increase chance for pollination since flowers are at the end of branches

• Everybody loves the fruit and seeds

•Consistent fruit production even in times of drought

Fishhook Barrel Cactus (Jiawul)

• Commonly 2 – 4’ but can be taller

• One barrel shaped stem

• Hooked central spine from areole

• Bloom in late summer

• Yellow fruit stay on plant for long time

• Taller plants tend to lean towards the Southwest

Hedgehog Cacti

• Up to 20” tall

• Multiple ribbed stem

• 2-4 central spines (one longer than the others)

• 12-14 shorter radial spines

• Spines are never hooked

• Flowers are purplish

Fishhook Pincushion Cactus

• Commonly 6” or less

• Pink flowers that grow in a ring; bright red fruit

• Stem is not ridged

• Central spine is hooked

• Densely packed spines from areoles

• Can have single stems or large clusters

• Often found under nurse shrubs and trees

Prickly Pear Cacti (I:ibhai)

• From 1’ to several feet high

• Flattened, jointed pads

• Flowers last one day

• Pads and fruits can be eaten

• Can reproduce from seed, or from fallen pads

• Several species in Sonoran Desert, with Engelmanns the most common

Jumping (Chain-fruit) Cactus

• Up to 8’ and taller

• Green fruit that stay on plant for long time and form in long chains

• Reproduce mostly from stem joints and fruit rind areoles

• Joints are loosely joined so if lightly brushed appear to jump

Teddybear Cholla

• 3-6’ tall

• Trunk is dark and nearly branchless

•Branches occur near top of plant

• Fruit are yellow and spineless

• Reproduce from joints where they fall on ground

Staghorn Cholla

• Similar to Buckhorn cholla, but fruit is spineless or lightly spined and stay on plant for more than a year

• 3’ – 15’ tall

• Stem is green to purplish in color

• Used for ciollem

Buckhorn Cholla

• Similar to Staghorn cholla, but fruit and buds are covered by spines

• 3’ – 15’ tall

• Stem is green to purplish in color

• Used for ciollem

• More common on Tohono O’odham reservation than staghorn cholla

Christmas Cholla

• Grows to 2’, but taller if inside other shrubs

• Segments thinner than pencil cholla

• Fruit bright red and stays on plant through winter

Pencil Cholla

• Can grow to 9’ tall, but usually less

• Each areole has 1 – 4 spines

• Longest at over 1” and downward facing