Projects: Chip Hedgcock & Mark A. Dimmitt


Chip and I are still mulling over what to do for our project. One idea is to showcase the plant lifeforms that are characteristic of the Sonoran Desert. Several lifeforms are unique or especially well represented in deserts. Their adaptations to aridity and intense sunlight give them odd forms that in turn make desert landscapes starkly different from other habitats. For example:


survive drought by storing water in their stems or leaves. They are common in arid habitats, and are most visible in deserts.

Agave zebra
Agaves have broad succulent leaves, often with marginal teeth and bold markings.
Bursera microphylla
(elephant tree) stores water in swollen stems that are often grotesquely twisted.
Ferocactus cylindraceus
(California fire barrel). Barrel cacti have massive, usually unbranched stems covered in fierce spines that protect the stored water from thirsty animals.


have seeds that germinate and grow only in unusually wet years. They complete their life cycles and die in a few weeks. Also called annuals, this lifeform occurs only in semiarid and arid habitats, and make up half or more of the plant species in deserts.

Camissonia claviformis
(yellow evening-primrose) grows on sandy soils after heavy fall rains.
Geraea canescens
(desert sunflower) grows on gravelly soils throughout the Sonoran and Mohave Deserts, often covering vast areas after rare wet winters.
Phacelia calthifolia
(Caterpillar weed) and Monoptilon bellioides (belly flower) go through a complete life cycle in a few months.
Psathyrotes ramosissima
(velvet cushion or turtleback) pops up in very dry gravels after a good rain.


plants have such sparse stems and foliage that you can see right through them. This life form was first recognized only in the 1990s by landscape architect Iain Robertson. Plants from wetter habitats usually have dense canopies.

Vachellia constricta
(whitethorn acacia) has a thin canopy even when in full leaf and flower.
Mariosousa willardiana
(palo blanco) provides almost no shade. On a summer day you could get heatstroke beneath it.
Asclepias albicans
(giant cane milkweed) has only a few stems and is almost completely leafless.
Eriogonum deflexum
(skeleton weed) grows about a foot tall. The basal leaves are dried up by the time the plant is in bloom.
Euphorbia florida
is an annual that grows up to a foot tall. It’s so wispy that it’s difficult to focus on.
Fouquieria splendens
(ocotillo), although it has bold stems, you can easily see through it even when it’s in full leaf and flower.
Muhlenbergia porteri
(bush muhly) is a shrubby grass that can grow two feet tall and 3-4 feet wide. Its stems are so fine that it looks like a fog from a distance.