Youngia Cass.

Herbs, annual or perennial with white latex; roots simple or rootstock stout; stem erect, stout or sometimes dwarf, glabrous or puberulous, solitary or branched; branches corymbosely spreading. Leaves chiefly radical, rarely alternate, rosulate, oblanceolate, obovate, spathulate, sinuate-toothed, often variously lobed; cauline leaves usually few, linear or linear-lanceolate. Inflorescence corymbosely panicled or terminal. Heads cylindric, erect; peduncle slender. Involucral bracts usually 2 - 3 seriate; outer ovate or obovate inner linear-lanceolate or oblong-lanceolate. Ligules yellow, 5-toothed. Stamens 5, appendaged; anthers slender, base sagittate. Stigma bifid; branches slender. Achenes brown, reddish brown, compressed or angular, narrowed into a stout beak, irregularly ribbed. Pappus white or silvery or dirty white, soft, simple.

Himalayan region eastwards to Japan from tropical, subtropical, temperate to alpine regions; ca 35 species, 13 in India.

Literature. BABCOCK, E.B. & G.L. Jr. STEBBINS (1937). The genus Youngia Carn. Inst. Wash. Publ. no. 484. 106.

KEY TO THE SPECIES

1a. Annual or perennial herbs; flowering branches long, usually many from the root or rootstock; heads few numerous

2

b. Perennial herbs; stems or flowering branches very short, stout, few from the rootstock; head, few, often solitary

9

2a. Annuals; densely corymbosely branched above

3

b. Perennials; broadly or loosely corymbosely branched above

6

3a. Pappus greyish

3. Youngia fuscipappa

b. Pappus white or yellowish

4

4a. Achenes longer than the pappus

4. Youngia glauca

b. Achenes equal to or shorter than the pappus

5

5a. Heads numerous, 4 - 6 mm long; peduncle bracteolate

7. Youngia japonica

b. Heads few, 8 mm long; peduncles ebracteolate

12. Youngia stebbinsiana

6a. Stems quite glabrous, grooved; leaves usually divided into many unequal lobes or segments; involucre glabrous or sparsely pubescent

13. Youngia tenuifolia

b. Stems glabrous or sparsely pubescent, not grooved; leave. thick, obovate or obovate-spathulate, with no segments; involucre densely tomentose

7

7a. Radical leaves not tapering; petiole usually simple, short, without wings, base simple

6. Youngia hondae

b. Radical leaves tapering to a long, simple or winged petiole

8

8a. Achenes 5 - 6 mm long, pappus 2 - 3 seriate

8. Youngia nilgiriensis

b. Achenes 4 - 4.5 mm long; pappus uniseriate

1. Youngia cineripappa

9a. Heads broad, campanulate

10

b. Heads cylindric

11

10a. Achenes columnar, subterete or 4-angled; pappus 10 - 11 mm long

11. Youngia simulatrix

b. Achenes compressed; narrowed at both ends, not angled; pappus 7 - 8.5 mm long.

5. Youngia gracilipes

11a. Flowering stems absent or very short; heads few; achenes 5 - 6 mm long with a pale beak

2. Youngia depressa

b. Flowering stems present, stout; heads few to many; achenes 3 - 4 mm long without a pale beak

12

12a. Plants quite glabrous; radical leaves narrowed into a short petiole, quite entire or obscruely toothed

10. Youngia silhetensis

b. Plants glabrous or puberulous; radical leaves narrowed into a long, winged petiole, usually sinuate toothed

9. Youngia recemifera

List of Lower Taxa