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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

MALACOTHRIX

W.S. Davis


Annual, perennial herb, < 70 (200) cm; sap milky. Stem: generally ± branched, generally erect, generally glabrous. Leaf: generally basal and cauline, alternate, sessile, sometimes reduced distally on stem, entire, toothed, or ± deeply pinnately lobed or divided. Inflorescence: heads liguliflorous; involucre generally bell-shaped; phyllaries in 3–6 series, mid-stripe green or ± red; receptacle flat to convex, shallowly pitted, glabrous or with fragile, smooth bristles < 5 mm, epaleate. Flower: corolla yellow or white, readily withering; ligules of outermost flowers exserted 1–15 mm, generally ± red- or purple-striped abaxially. Fruit: 0.9–4 mm, ± fusiform, tip truncate, generally smooth; ribs 15 (5 generally prominent, 10 ± obscure), generally extending to tip; outer pappus 0 or of teeth < 0.5 mm, or rounded-toothed crown, and 0–6 smooth, persistent bristles, inner pappus of 12–32 bristles fused at base, readily deciduous, minutely barbed proximally.
20 species: western North America, southern South America. (Greek: soft hair) [Davis 2006 FNANM 19:310–321] Anisocoma, Atrichoseris, and Calycoseris perhaps best placed here (Lee et al. 2003 Syst Bot 28:616–626).

Key to Malacothrix

1. Perennial herb (occasionally flowering first year)

2. Cauline leaves ± fleshy; ligules ± yellow; fruit smooth, outer pappus 0; dunes ..... M. incana

2' Cauline leaves generally not fleshy; ligules white; fruit minutely spiny, outer pappus of irregular teeth ..... M. saxatilis

3. Distal leaves generally 1–2-pinnately lobed

4. Stem densely leafy; distal leaves (ob)ovate, 2-pinnately divided into linear segments ..... var. implicata

4' Stem ± sparsely leafy; distal leaves linear to lanceolate, sharply and narrowly lobed ..... var. tenuifolia

3' Distal leaves generally entire (toothed)

5. Distal leaves generally linear to ovate, tip occasionally obtuse; coastal bluffs ..... var. saxatilis

5' Distal leaves lance-linear to elliptic, generally acute

6. Herbage tomentose ..... var. arachnoidea

6' Herbage glabrous to ± hairy ..... var. commutata

1' Annual

7. Plant scapose, stem unbranched, generally not visible above ground; heads borne singly on long, ± naked peduncles; outer phyllaries with ± tangled long hairs ..... M. californica

7' Plant with ± leafy stem, or if ± scapose, stem generally evident above ground, branched or not; heads generally borne in clusters; outer phyllaries glabrous, or ± short white-hairy

8. Cauline leaves generally with ear-like basal lobes; involucre generally spheric; outermost phyllaries widely ovate to round, margin widely scarious ..... M. coulteri

8' Cauline leaves generally without ear-like basal lobes; involucre generally bell-shaped; outermost phyllaries lanceolate to widely ovate

9. Cauline leaves not or seldom notably reduced distally on stem; Channel Islands

10. Fruit with outer pappus

11. Distal leaves generally oblanceolate, with few, short lobes; involucre 7–8.5 mm; fruit ribs ± equal, extending to tip; outer pappus of minute teeth and 1–2 bristles; Anacapa Island ..... M. junakii

11' Distal leaves narrowly ovate, with 5–10 narrow, ± sharp teeth or lobes; involucre 9–12 mm; 5 fruit ribs prominent, extending ± beyond tip; outer pappus of minute teeth, bristles 0(1); Anacapa, Santa Cruz islands ..... M. squalida

10' Fruit generally without outer pappus

12. Cauline leaves generally fleshy, margins ± equally lobed, tips obtuse; San Miguel, Santa Cruz, Santa Rosa islands ..... M. indecora

12' Cauline leaves generally not fleshy, lobes ± equal, generally sharp; Anacapa, San Clemente, San Nicolas, Santa Barbara islands ..... M. foliosa

13. Ligules of outermost flowers exserted < 5 mm

14. Stem 1–6, generally branched at base and distally; distal-most leaves distally sharply 4–10-lobed, ultimate margins curled; outer phyllaries ± overlapping; Anacapa Island ..... subsp. crispifolia

14' Stem generally 1, branched above base; distal-most leaves generally 2-lobed at base, ultimate margins generally not curled; outer phyllaries ± 1/2 inner phyllaries; San Nicolas Island ..... subsp. polycephala

13' Ligules of outermost flowers exserted generally > 5 mm

15. Stem generally 1, generally erect, branched distally; distal-most leaves generally 2-lobed at base; San Clemente Island ..... subsp. foliosa

15' Stems (1)3–5(10), erect, or decumbent to ascending; distal-most leaves generally pinnately lobed from base to near tip; Santa Barbara Island ..... subsp. philbrickii

9' Cauline leaves generally much reduced distally on stem; widespread, generally mainland habitats (Malacothrix clevelandii, Malacothrix similis also Channel Islands)

16. Ligules of outermost flowers exserted < 5 mm

17. Proximal cauline leaves ± fleshy, lobes in 3–8 pairs, short, ± equal, generally toothed; fruit outer pappus a rounded-toothed crown, bristles 0 ..... M. phaeocarpa

17' Proximal cauline leaves generally not fleshy, unequally toothed or narrowly lobed; fruit outer pappus of needle-like teeth, bristle generally 1

18. Basal leaves generally obovate in outline; corolla generally 6–8 mm, white or pale yellow; fruit generally 1.7–2.3 mm, ribs 0 near tip ..... M. stebbinsii

18' Basal leaves generally lance-linear to (ob)lanceolate in outline; corolla 4–9 mm, pale yellow to yellow; fruit 1.2–1.8 mm, ribs extending to tip

19. Stem generally branched mostly distally; cauline leaves generally toothed; pollen 70–100% 3-pored; common, widespread ..... M. clevelandii

19' Stem generally branched mostly from base; cauline leaves ± entire; pollen 70–100% 4-pored; uncommon, South Coast, n Channel Islands ..... M. similis

16' Ligules of outermost flowers exserted >= 5 mm

20. Ligules generally white (± yellow); fruit 1.2–2 mm; outer pappus 0; not of desert habitats ..... M. floccifera

20' Ligules yellow (white); fruit 1.8–3.3 mm; outer pappus present; often desert-like habitats

21. Leaf lobes ± equal, generally thread-like ..... M. glabrata

21' Leaf lobes short, ± equal, oblong, or triangular to linear

22. Distal-most leaves generally widest at base; outer pappus a rounded-toothed crown, bristles 0 ..... M. sonchoides

22' Distal-most leaves generally narrowed to strap-like base; outer pappus of irregular teeth, bristles (0)1–6 ..... M. torreyi

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