Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicotyledons

Order: Gentianales

Family: Gentianaceae -- gentian

Common Name: prairie gentian, pleated gentian

Species Code: GEAF

Origin: Native to mesic grasslands of western North America from southern British Columbia to northern California and east to Minnesota and western Texas. On the Palouse it prefers north facing hillsides.

Rare: no

Form: forb, perennial from thick, fleshy roots; stems erect to decumbent at the base, puberulent, 15-80 cm tall.

Duration: perennial

Longevity: medium lifespan

Habitat Type: prairie, forest

Wetland Indicator Status: FACU+

Leaves: opposite, 8-15 pairs, lowest reduced to bracts and sheathing, middle ovate to oblong-lanceolate, 2-5 cm long by 5-20 mm wide, glandular-ciliate near the base, margins rough-hairy; the leaves in the inflorescence similar, sometimes shorter and wider.

Mature height: 8-16 inches

Flowers: 5-merous, crowded, peduncles 3/25 mm long, bracteate; calyx tube 3-9 mm long, tubular-funnelform, greenish to bluish or purple, lobes unequal, flaring; corolla narrowly funnelform, 2-4.5 cm long, blue, often streaked with green, lobes oblong-ovate to ovate.

Flowers color: blue/purple

Bloom: July, August

Bloom starts on: late July

Bloom ends on: late August

Fruit: capsule; seeds elliptic, flattened, wing-margined.

Characteristics:
Both St. John (1963) and Piper & Beattie (1914) recognized the Palouse phase as G. oregana, a separate species from G. affinis but G. oregana is now usually included in G. affinis. Davis (1953) also recognized two separate species.
Reproduces sexually by seed.
4,846,154 seeds/lb (USDA NRCS Pullman PMC 2005).
Roots are fleshy.
Wide-ranging and variable, sometimes split into a number of separate species.
2n=26 (Baldwin et al 2004).
Flowers are perfect.
Fruit is a capsule.
Other species (G. saxosa and G. serotina) are protandrous (Webb & Littleton 1987).

Comments: The fleshy roots are fragile and easily damaged.

Sun requirement: full sun

Soil moisture: mesic

Sowing time: fall

Transplant time: spring

Stratification: Stratification increases germination rate

Seed yield: low

Seed harvest: difficult

Seed first harvest: second season

Seed cleaning: easy

Planting duration: moderate

Seed insect problem: none noted

Seed shatter: medium

Seed size: very small

Seed harvest date: early September to mid October

Seed comments: Flowering and seed ripening is indeterminate, germination is difficult.

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

Key words: native perennial upland forb

Propagation:
Reproduces sexually by seed.
Stratification appears beneficial but sufficient data are not available at present. A gibberellic acid presoak may be helpful.
Grow from seed or rooted stem pieces (Kruckeberg 1997).
Pacific Northwest species are difficult to grow (Hitchcock & Cronquist 1973).

Notes: Gentiana affinis seed germination is tricky but the flowers are worth the trouble. They bloom in late July and on through August, so the plants need to grow on moist sites like north slopes. Common name is prairie gentian (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 9/13/09 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.

Kruckeberg, Arthur R. 1996. Gardening with Native Plants of the Pacific Northwest. University of Washington Press. Seattle, WA.

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

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

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

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

Webb, C.J., and Jan Littleton. 1987. Flower Longevity and Protandry in Two Species of Gentiana (Gentianaceae). Annals of the Missouri Botanical Garden 74:51-57.

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