Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Order: Solanales

Family: Polemoniaceae -- phlox

Common Name: pink microsteris, slender phlox

Species Code: MIGR

Origin: Native in dry to moist grasslands and open forest of western North America from Alaska to California east to Montana, Nebraska, and New Mexico, extending into South America. Common and abundant.

Rare: no

Form: forb, annual from a taproot, highly variable; stems simple to branched, erect to decumbent, 5-30 cm tall, puberulent to glandular hairy, at least above.

Mature height: 2-12 inches

Duration: annual

Longevity: annual

Habitat Type: prairie, shrub thickets

Wetland Indicator Status: FACU

Leaves: upper alternate, linear to lance-linear to elliptic; lower opposite, 5-35 mm long, tending to be obovate or oblanceolate; sessile, 1-5 cm long, margins entire.

Flowers: borne in pairs at the end of branches, one flower pedicellate, the other subsessile; corolla 5-15 mm long, tube white or yellowish, 8-12 mm long, the 5 lobes pink to lavender, truncate or notched; calyx 5-10 mm long, somewhat accrescent, campanulate, glandular hairy.

Flower color: pink to white

Bloom: April, May, June

Bloom starts on: early April

Bloom ends on: late June

Fruit: capsule, 3-4 mm long, spheric to ovoid; seeds 1 per chamber, 2-2.5 mm long, brown, mucilaginous when wet.

Characteristics:
Often treated as Phlox gracilis. Gilia gracilis is an older synomym.
Of our local floras, Piper & Beattie treated it as Gilia gracilis and did not recognize infraspecific taxa. St. John (1963) also treated it as Gilia gracilis and recognized 2 varieties, var. gracilis and var. humilior. Davis 1953 elevated the two phases to the species level as M. gracilis and M. humilis. Hitchcock et al (1969) and Hitchcock & Cronquist (1973) treated it as M. gracilis and also recognized the two varieties. The two phases are separated mostly on the basis of var. gracilis being taller, less branched, and having a longer corolla with longer lobes and longer sepals.
Some floras may treat the phases at the subspecies level while others do not recognize infraspecific taxa at all, believing them to be part of a gradient within the species.
Reproduces sexually by seed.
Plant is an annual.
Flowers are perfect.
Fruit is a capsule.
292,080 seeds/lb (USDA NRCS Pullman PMC 2005).
2n=14 (Baldwin et al 2004).
Seeds are expelled explosively.

Sun requirement: full sun

Soil moisture: xeric

Sowing time: fall

Transplant time: not recommended

Stratification: cold moist

Seed yield: low

Seed harvest: difficult

Seed first harvest: annual

Seed cleaning: easy

Planting duration: annual

Seed insect problem: none noted

Seed shatter: high

Seed size: medium

Seed harvest date: June

Seed comments: capsules ripen indeterminately and dehisce explosively, making seed collection difficult

Herbaria: Specimen data and digital resources from The Consortium of Pacific Northwest Herbaria

Keywords: native annual upland forb

Alternate Genus: Phlox, Gilia

Propagation:
2 protocols in the Native Plant Network
Corvallis OR Plant Materials Center
Pullman WA Plant Materials Center

Other propagation information:
Germination of unstratified seed at warm temperatures is low. Seed germinates well at low temperatures. Best sown directly in the field in the fall.
Reproduces sexually by seed.

Notes: Microsteris gracilis is an annual that reseeds itself. There is not much to recommend about this species as a garden plant. It can be weedy but is usually so small it causes little harm. Seeds need to be stratified or fall sown. Other names include pink microsteris, Gilia gracilis, Phlox gracilis (Skinner et al 2005).

References:
Baldwin, B.G., S. Boyd, B.J. Ertter, D.J. Keil, R.W. Patterson, T.J. Rosatti, and D.H. Wilken (eds). 2004. Jepson Online Interchange for California Floristics. University and Jepson Herbaria, University of California, Berkeley, CA. Accessed 11/29/09 online at http://ucjeps.berkeley.edu/interchange.html

Davis, Ray J. 1952. Flora of Idaho. Wm. C. Brown, Dubuque, Iowa. 827 pp.

Hitchcock, C. Leo, and Arthur Cronquist. 1973. Flora of the Pacific Northwest. Univ. of Washington Press. Seattle, WA.

Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press. Seattle, WA. 5 vol.

Piper, C.V., and R.K. Beattie. 1914. The Flora of Southeastern Washington and Adjacent Idaho. Press of the New Era Printing Company, Lancaster, PA. 296 pp.

Skinner, David M., Paul Warnick, Bill French, and Mary Fauci. 2005. More Palouse Forbs for Landscaping. USDA NRCS Pullman Plant Materials Center and Palouse Prairie Foundation. Online at http://www.wsu.edu/pmc_nrcs/Docs/More_Forbs_for_Landscaping.pdf

St. John, Harold. 1963. Flora of Southeastern Washington and of Adjacent Idaho. 3rd edition. Outdoor Pictures. Escondido, CA.

USDA NRCS, Pullman Plant Materials Center. 2005. Seed Weights of Some Palouse Native Species. Pullman Plant Materials Center, Pullman, Washington. Online at http://www.wsu.edu/~pmc_nrcs/Docs/Seed_Weights_Palouse_Native_Species.pdf

Links:
Plant Profile from the USDA PLANTS Database
Species information from the University of Washington Herbarium