{{Short description|Genus of flowering plants}} {{Speciesbox |image = Microsteris_gracilis_1776.JPG |genus = Microsteris |parent_authority = Greene (1898) |species = gracilis |authority = (Hook.) Greene (1898) |subdivision_ranks = Varieties |subdivision = *''Microsteris gracilis'' var. ''gracilis'' *''Microsteris gracilis'' var. ''humilior'' {{small|(Hook.) Cronquist}} | subdivision_ref = <ref name = powo>[https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:160572-2 ''Microsteris gracilis'' (Hook.) Greene]. ''Plants of the World Online''. Retrieved 19 April 2024.</ref> |synonyms = *''Myotoca'' {{small|Griseb. (1856)}} *''Collomia gracilis'' {{small|(Hook.) Douglas ex Benth. (1834)}} *''Gilia gracilis'' {{small|Hook. (1829)}} *''Navarretia gracilis'' {{small|(Hook.) Kuntze (1891)}} *''Phlox gracilis'' {{small|(Hook.) Greene (1887)}} *''Polemonium morenonis'' {{small|Kuntze (1898)}} |synonyms_ref = <ref name = powo/> }}

'''''Microsteris''''' is a monotypic 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''.<ref>Prather, L. A., C. J. Ferguson, and R. K. Jansen. (2000). [https://web.archive.org/web/20030728174541/http://www.amjbot.org/cgi/content/full/87/9/1300 Polemoniaceae phylogeny and classification: implications of sequence data from the chloroplast gene ''ndhF''.] ''American Journal of Botany'' 87 1300-08.</ref><ref>Ferguson, C. J. and R. K. Jansen. (2002). [https://web.archive.org/web/20030801221716/http://www.amjbot.org/cgi/content/full/89/8/1324 A chloroplast DNA phylogeny of eastern ''Phlox'' (Polemoniaceae): implications of congruence and incongruence with the ITS phylogeny.] ''American Journal of Botany'' 89 1324-35.</ref> Genetic analysis is continuing.

==Distribution== ''Microsteris gracilis'' is native to western North America from northwestern Canada to the American Midwest and West Coast, through Mexico, as well as parts of South America. It is native to all the diverse plant communities in California.<ref>[http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5654,5899,5907 Jepson eFlora: Distribution map for ''Microsteris gracilis'' in California]</ref>

left|thumb|upright|The flower has a tubular yellow throat encased in a tubular gladular-hairy calyx. Corolla lobes are just 1 to 2 mm long.

==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.

==References== {{Reflist}}

==External links== *[http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5654,5899,5907 Jepson Manual Treatment of ''Microsteris gracilis''] *[https://plants.usda.gov/java/profile?symbol=MIGR USDA Plants Profile for ''Microsteris gracilis'' (slender phlox)] *[http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Microsteris+gracilis ''Microsteris gracilis'' — U.C. Photo gallery] {{Commons category|Microsteris gracilis|position=left}}

{{Taxonbar|from=Q15396409}}

Category:Monotypic Ericales genera Category:Polemoniaceae Category:Flora of Mexico Category:Flora of Western Canada Category:Flora of the Northwestern United States Category:Flora of the Southwestern United States Category:Flora of California Category:Flora of Nebraska Category:Flora of South Dakota Category:Flora of Southern America Category:Flora of the California desert regions Category:Flora of the Cascade Range Category:Flora of the Great Basin Category:Flora of the Klamath Mountains Category:Flora of the Sierra Nevada (United States) Category:Natural history of the California chaparral and woodlands Category:Natural history of the California Coast Ranges Category:Natural history of the Peninsular Ranges Category:Natural history of the Transverse Ranges Category:Polemoniaceae genera Category:Flora without expected TNC conservation status Category:Plants described in 1829 Category:Taxa named by William Jackson Hooker