Stellaria obtusa at Horsepasture

Yesterday, Sabine, Ingrid, and I went to Horsepasture. The Ipomopsis aggregata was at peak and the hummers were going nuts. It was also peak time for the Antennaria luzuloides. The little propagules are forming on non-flowering branches.

Stellaria obtusa

Stellaria obtusa at Horsepasture Mountain

The only interesting addition/change to the list is that the Stellaria there is obtusa, not crispa. There is some growing along the trail right at the beginning by the road and again before the first damp Alder thicket. I’d never heard of this species before this year when I finally attempted to sort out the Stellarias. I’d seen it on the list for Grizzly Peak near Ashland and was pleased to find it blooming there when I went down in June. Since then I’ve been looking carefully at every patch of low-growing Stellaria. In the past, I found them easily ignorable and assumed they were all crispa, so all my listings for that one are now suspect. John and I discovered it at Wild Rose Point over the border in Douglas County a couple of weeks ago. Then last week, I saw it growing all along the Buck Canyon trail in the Rogue-Umpqua Divide. My next 2 hikes there were just over the ridge and I expected to see it again, but instead found some small patches of S. crispa. My trip to Blair last week also turned up several patches of S. crispa.

Stellaria obtusa at Wild Rose Point

Stellaria obtusa at Wild Rose Point. The styles show better in this photo.

While they are anything but showy or exciting, there are few instances of S. obtusa on the OFP Atlas and only one in Lane County, so it is something that needs more research. I suspect the reason is because most people, including me, didn’t recognize it as being different from S. crispa, ignored it, or had never heard of it. I bet it is not as uncommon as the Atlas map would imply. We should keep an eye out for it elsewhere in Lane County. While the habitat seems to be the similar—somewhat shady, damp areas half hidden under other plants—there are several differences in flower structure.

Stellaria obtusa “always” (I should always be careful using that word!) has 4 sepals which are blunt at the tips. It does not have any petals. Most of the ones I’ve seen have 4 styles that are curled back. The capsule is globose. The leaves have some marginal hairs along the base. The plant stays close to the ground in a tangled mat.

Stellaria crispa at Blair Meadows

Stellaria crispa at Blair Meadows. It has a couple of tiny petals and crisped leaves.

Stellaria crispa has 5 sepals (although some of the ones at Blair had 4) with long sharp points. It may have some squinny petals. It has 3 styles which are normally spreading (although the one in my photo from Blair is curled back). The capsule is longer than wide. The leaves of the ones that I’ve seen are all glabrous. They are often “crisped” along the edges. I wonder if the reason I didn’t trust this feature is because I was seeing obtusa sometimes, which doesn’t have the rippled or “crisped” edges. Looking at my recent photos of S. crispa (including Blair below), they are in fact crisped. The plant is sprawling but can reach up relatively higher and is generally looser than S. obtusa, with more space between leaves and longer pedicels. I don’t agree with their assessment of the “prominent” veins—I can’t see them—but I have included the FNA treatments below for anyone who’s interested in anything this drab.


Flora of North America treatments

22. Stellaria obtusa Engelmann, Bot. Gaz. 7: 5. 1882.

Blunt-sepaled starwort, Rocky Mountain starwort

Alsine obtusa (Engelmann) Rose; A. viridula Piper; A. washingtoniana (B. L. Robinson) A. Heller; Stellaria viridula (Piper) St. John; S. washingtoniana B. L. Robinson

Plants perennial, creeping, often matted but not forming cushions, rhizomatous. Stems prostrate, branched, 4-sided, 3-23 cm, internodes equaling or longer than leaves, glabrous, rarely pilose. Leaves sessile or short-petiolate; blade broadly ovate to elliptic, 0.2-1.2 cm × 0.9-7 mm, base round or cuneate, margins entire, apex acute, shiny, glabrous or ciliate near base. Inflorescences with flowers solitary, axillary; bracts absent. Pedicels spreading, 3-12 mm, glabrous. Flowers 1.5-2 mm diam.; sepals 4-5, veins obscure, midrib sometimes apparent, ± ovate, 1.5-3.5 mm, margins narrow, scarious, apex ± obtuse, glabrous; petals absent; stamens 10 or fewer; styles 3(-4), curled, shorter than 0.5 mm. Capsules green to pale straw colored, translucent, globose to broadly ovoid, 2.3-3.5 mm, 1.9-2 times as long as sepals, apex obtuse, opening by 6 valves; carpophore absent. Seeds grayish black, broadly elliptic, 0.5-0.7 mm diam., finely reticulate. 2n = 26, 52, ca. 65, ca. 78.

Flowering late spring-summer. Moist areas in woods, shaded edges of creeks, talus slopes; 300-3400 m; Alta., B.C.; Calif., Colo., Idaho, Mont., Oreg., Utah, Wash., Wyo.

8. Stellaria crispa Chamisso & Schlechtendal, Linnaea. 1: 51. 1826.

Crisp starwort

Alsine crispa (Chamisso & Schlechtendal) Holzinger; Stellaria borealis Bigelow var. crispa (Chamisso & Schlechtendal) Fenzl ex Torrey & A. Gray

Plants perennial, forming small to large mats, from slender rhizomes. Stems trailing to ascending, branched, 4-angled, 10-60 cm, glabrous. Leaves subsessile; blade broadly elliptic to ovate, 0.4-2.6 cm × 2-15 mm, base round to cuneate, margins entire, apex acuminate, glabrous or with a few scattered cilia. Inflorescences with flowers solitary in leaf axils; bracts absent. Pedicels ascending, straight, mostly 5-30 mm, glabrous. Flowers 4-5 mm; sepals 5, prominently 3-veined, lanceolate, 2-4 mm, margins broadly scarious, apex acute to acuminate, glabrous; petals usually absent, rarely 1-5 and much shorter than sepals; stamens 10 or fewer; styles 3, spreading to ascending, curved but not curled, ca. 1 mm. Capsules straw colored or brownish, ovoid to ovoid-ellipsoid, 3.5-6 mm, equaling or slightly exceeding sepals, apex broadly acute, opening by 6 valves; carpophore absent. Seeds brown, broadly elliptic, 0.7-1 mm (longest axis), distinctly rugose. 2n = 26, 52.

Flowering summer. Wet soil in woods, shaded streambanks and shores; 0-2300 m; Alta., B.C.; Alaska, Calif., Idaho, Mont., Oreg., Wash.

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