Microsteris is a genus of flowering plants in the phlox family containing the single species Microsteris gracilis, known by the common name slender phlox.
The segregation of this species into a genus of its own is controversial, and many botanists continue to include the plant in genus Phlox.Ferguson, C. J. and R. K. Jansen. (2002). A chloroplast DNA phylogeny of eastern Phlox (Polemoniaceae): implications of congruence and incongruence with the ITS phylogeny. American Journal of Botany 89 1324-35. Genetic analysis is continuing.
Description
Microsteris gracilis is an annual herb which is variable in shape, taking a decumbent, branching, sometimes almost tuftlike form or growing erect and very slender. Its maximum height approaches 20 centimeters, but it may be much smaller.
The lance-shaped leaves are 1 to 3 centimeters long and oppositely arranged except for the upper ones, which are alternate. The herbage is glandular and hairy in texture. The inflorescence at the top of the stem bears one or more small flowers.
The flower has a tubular throat around a centimeter long encased in a tubular calyx of sepals. The flat corolla has five flat-tipped or notched lobes just 1 or 2 millimeters long. The flower is white to bright pink with a yellowish throat.
Taxonomy In 1829 William Jackson Hooker named a new species in the Gilia genus, Gilia gracilis. The genus Microsteris was named and described by Edward Lee Greene, including Microsteris gracilis. Together with its genus the species is classified in the Polemoniaceae family.
Although Microsteris is monotypic genus species names have been created that are a synonym another species or one of its two accepted varieties.
Table of Species Name Year Synonym of: Notes Microsteris andicola 1898 var. gracilis = het. Microsteris californica 1898 var. gracilis = het. Microsteris depressa 1923 L. depressum ≡ hom. Microsteris diffusa 1899 var. gracilis = het. Microsteris gilioides 1923 A. gilioides ≡ hom. Microsteris glabella 1898 var. humilior = het. Microsteris heterophylla 1947 var. gracilis = het., without a Latin descr. Microsteris humilis 1898 var. humilior = het. Microsteris larsenii 1947 C. larsenii ≡ hom. Microsteris macdougalii 1899 var. gracilis = het. Microsteris micrantha 1898 var. gracilis = het. Microsteris stricta 1898 var. gracilis = het. Microsteris traskiae 1923 var. gracilis = het. Notes: ≡ homotypic synonym; = heterotypic synonym
The genus Myotoca with the single species Myotoca eritrichoides was created in 1907 by August Brand and attributed to August Grisebach and is synonymous with Microsteris and variety gracilis respectively. In addition there are five alternate classifications for the species that are homotypic synonyms.
Table of Synonyms Name Year Collomia gracilis 1834 Gilia gracilis 1829 Navarretia gracilis 1891 Phlox gracilis 1887 Polemonium morenonis 1898
Names The genus name, Microsteris, is a Botanical Latin compound meaning 'tiny star', a reference to the small, star shaped flower.
Distribution Microsteris gracilis is native to western North America from northwestern Canada to the American Midwest and West Coast, through Mexico, as well as South America from Peru to southern Chile.
In Canada it does sometimes occur in the Yukon, but its has not established a recurring population. It is stated to be introduced to the Yukon in the Flora of Alberta, but is listed as native in Plants of the World Online. In British Columbia and Alberta it is found in southern parts of the provinces. In the northwestern United States it is common throughout Washington and Oregon, mostly found in southern Idaho, and widely scattered in Montana. Southward in Wyoming it is recorded in all but four counties and is found on both the western and eastern slopes of Colorado. It reaches its easternmost native distribution in a few western counties of South Dakota and Nebraska.
In the southwestern US the species is native to all the diverse plant communities in California, with records in almost every county. It is likewise found in all but one county in Nevada and all but five counties in Utah. Plants grow in most of Arizona, but only in western counties of New Mexico. South of the border it is found in just two northwestern Mexican states, Baja California and Sonora.
References Citations
Sources Books
Journal articles
Web sources
External links
USDA Plants Profile for Microsteris gracilis (slender phlox) Microsteris gracilis — U.C. Photo gallery