Littleleaf Silverback

Stems spreading or erect. Leaves sessile; blades ovate to lanceolate, 18–65 × 7–40 mm, abaxially lanate, adaxially usually glabrous and shiny, rarely sparsely tomentulose, then usually glabrescent. Peduncles 10–50 mm. Phyllaries 6–14, ovate to lanceolate, 5–9 mm. Florets 11–23; corollas pale yellow, 8–11 mm. Cypselae 3–4 mm, 9-nerved, glabrous or strigose; pappi of 80–120 bristles 8–10 mm. 2n = 60.

Luina hypoleuca Benth. in Hook. Ie. PI. 12; 36. 1873
A perennial, with a rootstock covered with fuscous scales; stem 2-5 dm. high, whitetomentose; leaves alternate, sessile, ovate or oval, entire, acute, 2-6 cm. long, 3-7-ribbed, reticulate, loosely floccose, at last glabrate and shining above, white-tomentose beneath; heads corymbose; individual peduncles 1-2 cm. long; involucre oblong-campanulate, about 7 mm. high, 8-10 mm. broad; bracts about 12, keeled, lanceolate, acuminate, at first floccosetomentose, in age glabrate; corolla nearly 1 cm. long; tube slender, nearly equaling the cylindro-funnelform throat; lobes lanceolate, 1 mm. long; anthers 4 mm. long; style-branches 2 mm. long; achenes brown, 3 mm. long; pappus-bristles about 8 mm. long.
Type locality: Lake Chilukweynk, Cascade Mountains.
Distribution: Cascade Mountains from Oregon to British Columbia, and on Vancouver Island.

Luina californica (A. Gray) Rydberg, sp. nov
Luina hypoleuca californica A. Gray, Proc. Am. Acad. 9: 206. 1874.
A perennial, similar to the preceding, with a short branched woody rootstock, covered with dark-brown scales; stem white-tomentose, 2-3 dm. high; leaves broadly oval or the lower obovate, acute, entire, 1-3 cm. long, 5-7-ribbed and reticulate, rather permanently floccose above, densely white-tomentose beneath heads corymbose; individual peduncles about 1 cm. long; involucre about S mm. high and broad; bracts linear, acuminate, carinate, densely white-tomentose; corolla as in the preceding, but the lobes ovate, less than 1 mm. long.
Type locality: Behind Santa Cruz. California.
Distribution: Coast Range of California, from Santa Cruz northward.

Luina hypoleuca, the littleleaf silverback, is a species of the genus Luina and the family Asteraceae. It grows to 40 centimetres (16 inches) in height, its leaves 2.5–6.5 cm (1–2+1⁄2 in) long and white on the underside (hence the specific epithet, meaning 'bottom white'). It flowers between June and October, with yellowish rayless flower heads about 9 millimetres (3⁄8 in) long. It is found in North America on open and usually rocky places between elevations of 70–2,100 metres (230–6,890 feet) in British Columbia, California, Oregon, and Washington.

Top view

Leaf bottom

Luina hypoleuca là một loài thực vật có hoa trong họ Cúc. Loài này được Benth. mô tả khoa học đầu tiên.