The Desert Tortoise Natural Area (DTNA) is a 39.5 square mile area of prime natural habitat located in the Mojave Desert of California on the slopes of the Rand Mountains. This desert ecosystem includes over 160 different species of plant. Many of the animal inhabitants of the DTNA feed upon these plants. One such inhabitant is the desert tortoise (Gopherus (Xerobates) agassizii), Official Reptile of the State of California.
Desert tortoises in their native habitat feed on annual wild flowers, annual and perennial grasses, and the pads and buds of some cactus species. The term "annual" designates those plants which complete their life cycle in one season. These plants germinate, grow, flower, set seed, and die in one growing season. The seed they have set will germinate and grow under the right conditions the following season. Perennial plants may live through several to many seasons. The roots and underground stems of some perennial plants remain alive through the seasons even when the above ground portions of the plants die back each year; these are known as herbaceous perennials.
Seeds of many of the annual wildflowers on which desert tortoises feed are available from Theodore Payne Foundation. The following paragraphs describe these annuals in more detail.
Leafy-Stemmed Coreopsis (Coreopsis calliopsidea) grows from 4 to 20 inches (10-50 cm) in height and bears 1 to 3 inch (2.5-7.5 cm) wide golden flowers.
Whispering Bells (Emmenanthe penduliflora) grow from 4 to 20 inches (10-50 cm) in height and bear small, yellowish-cream flowers resembling bells.
Gold Fields (Lasthenia chrysotoma) is a slender annual growing 2 to 10 inches (5-25 cm) tall with small yellow flowers, and which carpets the desert after the winter rains.
White Tidy-Ups (Layia glandulosa) grow 12 to 24 inches (30-60 cm) in height and bear numerous flowers which are 1 inch (2.5 cm) across and white with yellow centers.
Desert Dandelion (Malacothrix glabrata) is a many-stemmed annual 4 to 15 inches (10-38 cm) tall which bears numerous pale-yellow, fragrant flowers.
Owl's Clover (Orthocarpus purpurascens) is also known as Pink-Brush, referring to its appearance in flower. It grows 4 to 15 inches (10-38 cm) in height and bears striking flowers which are greenish-purple at the base and reddish-purple at the tip.
Thistle Sage (Salvia carduacea) is an annual growing with a rosette of prickly leaves at the base of 12 to 24 inch (30-60 cm) tall stalks of lavender-fringed flowers each about 1 inch (2.5 cm) long.
Chia (Salvia columbariae) grows in well-drained locations to a height of 4 to 20 inches (10-50 cm), bearing clusters of blue-purple flowers and edible seeds.
Theodore Payne also offers a desert-annual seed mix composed of many plant species, some of which are native to the DTNA and some of which are not.
Several perennials native to the DTNA are available as seed or one-gallon container plants. Among these are the following:
Bluedicks (Dichelostemma pulchellum), which send up a few grass-like leaves and numerous flower stalks 12 to 24 inches (30 -60 cm) tall from small onion-like bulbs (grassnuts). Bluedicks have pale-blue to purple flowers.