{{Short description|Genus of flowering plants}} {{Speciesbox |image = Platystemon californicus, Shell Creek Road.jpg |status = G5 |status_system = TNC |status_ref = |display_parents = 3 |genus = Platystemon |parent_authority = Benth. |species = californicus |authority = Benth. }}

'''''Platystemon''''' is a monotypic genus of flowering plants in the poppy family containing the single species '''''Platystemon californicus''''', which is known by the common name '''creamcups'''.<ref>{{PLANTS|id=PLCA5|taxon=Platystemon californicus|accessdate=7 October 2015}}</ref> It is native to Oregon, California, Arizona, Utah and Baja California, and is found in open grasslands and sandy soils below {{Convert|6000|feet|-2}} elevation.<ref name="Jepson">{{cite web | url= http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=Platystemon%20californicus | date= 2018 | title= Platystemon californicus | website= in Jepson Flora Project (eds.) Jepson eFlora | publisher= Jepson Herbarium; University of California, Berkeley | accessdate= 2018-07-06}}</ref><ref name="Sullivan2018">{{cite web | url= http://www.wildflowersearch.com/search?&PlantName=Platystemon+californicus | last= Sullivan | first= Steven. K. | date= 2018 | title= ''Platystemon californicus'' | website= Wildflower Search | accessdate= 2018-07-06 }}</ref>

==Description== ''Platystemon californicus'' is a variable plant taking such a wide range of forms it has been split, reorganized, and redescribed as up to 57 different species. Its form often varies according to geography and habitat conditions. Coastal forms may be hairless and a bit succulent, while semidesert individuals can be squat, hairy plants. Some authors describe separate varieties, which are ecotypes adapted to specific, often very limited, habitat types.<ref name=fna>[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500965 ''Platystemon californicus''.] Flora of North America.</ref>

The annual herb is usually at least a bit hairy, sometimes quite woolly. The stem is upright to decumbent and 3 to 30 centimeters long. The leaves are oppositely arranged or whorled about the stem. They are widely linear and smooth-edged with rounded or pointed tips. They are 1 to 9 centimeters long. The inflorescence is a single flower growing from a leaf axil or the tip of the stem. It is borne on a peduncle 3 to 26 centimeters long with three hairy sepals.<ref name="Jepson"/> The flower usually has six petals, but a large flower can have more. The petals vary in size, shape, and color. They measure 6 to 19 millimeters long and have rounded or pointed tips.<ref name=fna/> There are five basic color patterns: solid white, solid yellow, and a white petal with a yellow tip or yellow base or both.<ref name=han>Hannan, G. L. (1982). [https://www.jstor.org/discover/10.2307/2418651?uid=3739560&uid=2&uid=4&uid=3739256&sid=21102535517347 Correlation of morphological variation in ''Platystemon californicus'' (Papaveraceae) with flower color and geography.] ''Systematic Botany'' 7(1) 35-47.</ref> The all-yellow petals are less common. The petals may age reddish. The center of the flower is filled with several whorls of stamens with thickened ends. The fruit is a capsule up to 1.6 centimeters long which is divided into many sections containing shiny black seeds.<ref name=fna/>

The flowers are partly wind-pollinated and partly pollinated by solitary bees.<ref>Hannan, G. L. (1981). [https://www.jstor.org/discover/10.2307/2442855?uid=3739560&uid=2&uid=4&uid=3739256&sid=21102535517347 Flower color polymorphism and pollination biology of ''Platystemon californicus'' Benth.(Papaveraceae).] ''American Journal of Botany'' 68(2) 233-43.</ref> left|thumb|upright|Desert individuals may be quite woolly or shaggy with whorled basal leaves. Flower buds are nodding with three overlapping and loosely touching sepals.<ref name=fna/> ==References== {{Reflist}}

==External links== *{{Commons-inline|Platystemon californicus|''Platystemon californicus''}} *[http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Platystemon+californicus ''Platystemon californicus''.] CalPhotos.

{{Taxonbar|from1=Q1029455|from2=Q15321448}}

Category:Monotypic Papaveraceae genera Category:Papaveroideae Category:Flora of Arizona Category:Flora of Baja California Category:Flora of California Category:Flora of Oregon Category:Flora of Utah