''Coleogyne ramosissima'' or blackbrush, is a low lying, dark grayish-green, aromatic,Turner, Raymond M. 1982. Great Basin desertscrub. In: Brown, David E., ed. Biotic communities of the American Southwest--United States and Mexico. Desert Plants. 4(1-4): 145–155. spiny,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

, soft wooded shrub, native to the deserts of the

southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

.Mojave Desert Wildflowers, Pam MacKay, p18, 252Canyon Country Wildflowers, Damian Fagan, p 3, 105 It is called blackbrush because the gray branches darken when wet by rains. It is in the rose family (

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are '' Alchemilla'' (270), '' Sorbu ...

), and is the only species in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Coleogyne''.

Growth pattern

It has dense, intricate branches ("ramosissima" means "many branched"). Its dense branches form spiny tips. This plant forms vast pure stands across the desert floor and on scrubby slopes, giving the landscape a uniform dark-gray color. Vegetative types in which it dominates or is a codominate are called blackbrush scrub. It drops most of its leaves and becomes dormant in conditions of severe dryness ( drought-deciduous), but some leaves are usually retained at the end of the branches. The thickly branched plant forms thickets which may spread across the ground in clumps or grow erect to approach six feet in height in the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily i ...

, and 4 feet in the Canyonlands desert region.

Flowers

Flowers have 4 yellowish sepals, many yellow stamens, and may have 4 or no petals. It is atypical of members of the rose family in that the flowers have no

petals Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...

, have four rather than five

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

, and the leaves are opposite (occur in pairs on the twig), rather than alternate (occurring one at a time going up the twig.California Desert Flowers, Sia Morehardt, Emil Morehardt, p 232, 264 The sepals may persist on the plant. It flowers between April and July.

Leaves

The leaves are inversely lanceolate, up to 3/8" long, have a small point at the tip, and are arranged in opposite pairs along the stem, which is uncommon in members of the rose family. It forms vast communities in the Canyonlands region, and in the Mojave Desert. Flowering is triggered by a heavy spring rain in this desert-adapted species. The leathery flowers grow at the ends of small stems. They are encased in thick, fuzzy

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined ...

s which are yellow inside and reddish or orange on the outer surface. There are no petals, but the sepals remain after the flower opens, surrounding the patch of whiskery

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s and the central

pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pis ...

. The fruit is an

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not op ...

a few millimeters long. The plant reproduces from seed, but very rarely. The seeds do not disperse well and seedlings do not survive in large numbers. A narrow range of temperature and moisture is required for the reproduction of this species, so it is sporadic, but the plants are hardy and long-lived. ''Coleogyne ramosissima'' produces stenophyllanin A, an ellagitannin.Anti-tumor promoting activity of polyphenols from ''Cowania mexicana'' and ''Coleogyne ramosissima''. Hideyuki Ito, Masateru Miyake, Eisei Nishitani, Kazuko Mori, Tsutomu Hatano, Takuo Okuda, Takao Konoshima, Midori Takasaki, Mutsuo Kozuka, Teruo Mukainaka, Harukuni Tokuda, Hoyoku Nishino and Takashi Yoshida, Cancer Letters, Volume 143, Issue 1, 23 August 1999, Pages 5-13,

References

External links

Jepson Manual TreatmentUSDA Plants ProfilePhoto gallery
{{Taxonbar, from1=Q15949848, from2=Q2716790 Kerrieae Monotypic Rosaceae genera North American desert flora