{{Short description|Genus of flowering plants}} {{For|blackbrush acacia|Acacia rigidula}} {{Use dmy dates|date=May 2020}} {{Speciesbox | image = Coleogyne ramosissima 4.jpg | image_caption = | display_parents = 3 | genus = Coleogyne | parent_authority = Torr.<ref>{{GRIN | accessdate=2009-07-01}}</ref> | species = ramosissima | authority = Torr. }}
'''''Coleogyne ramosissima''''' or '''blackbrush''', is a low lying, dark grayish-green, aromatic,<ref name=GBDS>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.</ref> spiny, perennial, soft wooded<ref name=GBDS/> shrub, native to the deserts of the southwestern United States.<ref name=MDW>Mojave Desert Wildflowers, Pam MacKay, p18, 252</ref><ref name=CCW>Canyon Country Wildflowers, Damian Fagan, p 3, 105</ref> It is called blackbrush because the gray branches darken when wet by rains.<ref name=MDW/><ref name=CCW/> It is in the rose family (Rosaceae)<ref name=MDW/><ref name=CCW/> and is monotypic (the only species in its genus).
==Growth pattern== {{Further|Blackbrush scrub}} It has dense, intricate branches ("ramosissima" means "many branched").<ref name=CCW/> Its dense branches form spiny tips.<ref name=CCW/> This plant forms vast pure stands across the desert floor and on scrubby slopes, giving the landscape a uniform dark-gray color.<ref name=MDW/> Vegetative types in which it dominates or is a codominate are called blackbrush scrub.<ref name=MDW/><ref name=CCW/>
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.<ref name=MDW/> 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,<ref name=MDW/> and 4 feet in the Canyonlands desert region.<ref name=CCW/>
==Flowers== Flowers have 4 yellowish sepals, many yellow stamens, and may have 4 or no petals.<ref name=CCW/> It is atypical of members of the rose family in that the flowers have no petals, have four rather than five sepals, and the leaves are opposite (occur in pairs on the twig), rather than alternate (occurring one at a time going up the twig.<ref name=MDW/><ref name=CDF>California Desert Flowers, Sia Morehardt, Emil Morehardt, p 232, 264</ref> The sepals may persist on the plant.<ref name=CCW/> 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,<ref name=CCW/> which is uncommon in members of the rose family.<ref name=CDF/>
It forms vast communities in the Canyonlands region,<ref name=CCW/> and in the Mojave Desert.<ref name=MDW/>
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 sepals 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 stamens and the central pistil. The fruit is an achene 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.<ref>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, {{doi|10.1016/S0304-3835(99)00160-3}}</ref>
==References== {{Reflist}}
==External links== *[http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?6677,6711,6712 Jepson Manual Treatment] *[https://plants.usda.gov/java/profile?symbol=CORA USDA Plants Profile] *[http://www.fs.fed.us/database/feis/plants/shrub/colram/all.html Ecology] *[http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Coleogyne+ramosissima Photo gallery]
{{Taxonbar|from1=Q15949848|from2=Q2716790}}
Category:Kerrieae Category:Monotypic Rosaceae genera Category:North American desert flora