Leuzea DC.

131. Leuzea DC. 1

( Rhaponticum Adanson , non Ludwig)

Biennials or perennials. Stem simple, rarely sparingly branched. Leaves entire to lyrate or pinnatifid. Capitula solitary, terminal. Involucre ovoid-globose or globose; bracts imbricate, with membranous, entire or lacerate appendages. Florets all hermaphrodite. Anthers with obtuse basal appendages. Achenes ovoid or turbinate, sometimes compressed, glabrous; pappus-hairs in several rows, plumose or barbellate, connate into an annulus at the base.

Literature: J. Holub, Folia Geobot. Phytotax. (Praha) 8: 377-395 (1973). 1 Pappus-hairs barbellate, the cilia not or scarcely longer than the width of the hair

2 Bracts narrowly lanceolate, acuminate, without a distinct appendage; basal leaves pinnatisect 1. centauroides 2 Bracts broadly ovate, obtuse or subacute, with an orbicular appendage up to 10 mm wide; basal leaves undivided, lyrate or pinnatisect 2. rhapontica 1 Pappus-hairs plumose, the cilia at least 3 times as long as the width of the hair

3 Stem 5-30 cm; involucre ovoid-globose; achenes densely tuberculate, without an apical collar; pappus c. 6 times as long as achene, the cilia 10-20 times as long as the width of the hair 4. conifera 3 Stem 20-150 cm; involucre globose; achenes ±smooth, with a small apical collar; pappus 2-3 times as long as achene,

the cilia not more than 8 times as long as the width of the hair

4 Stem 20-80 cm, leafless above; leaves white-tomentose beneath 6. longifolia 4 Stem 40-150 cm, with a few leaves above; leaves green on both surfaces or arachnoid-hairy beneath

5 Stem 100-150 cm; leaves pinnatifid; involucre 6-8 cm in diameter; appendages of involucral bracts suborbicular,

the outer lanceolate 5. rhaponticoides 5 Stem 40-100 cm; leaves undivided or with 1-3 pairs of lobes at the base; involucre 3-6 cm in diameter; appendages of involucral bracts ovate, long-acuminate 3. altaica