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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.

 

LAYIA

Bruce G. Baldwin & Susan J. Bainbridge


Annual 2–6(13) dm. Stem: generally ascending to erect, often glandular, generally ± purple or brown. Leaf: basal in rosette or opposite, cauline generally alternate, sessile, generally linear to lanceolate, or oblanceolate, minutely dentate to (2-)pinnately lobed, glabrous or hairy, distal often stalked-glandular. Inflorescence: heads generally radiate, 1 or in ± open clusters; involucre ± hemispheric to bell-shaped, obconic, or urn-shaped, 2–15+ mm diam; phyllaries 1 per ray flower, in 1(2) series, lanceolate to oblanceolate, generally folded completely around ray ovary, falling with fruit, generally ± hairy or scabrous, often glandular; receptacle flat to slightly convex, minutely bristly, paleae free, generally in 1 series between ray and disk flowers, or subtending ± each disk flower, phyllary-like, more scarious. Ray flower: (0)3–27; corolla white, often aging ± pink, to yellow or proximally yellow and distally pale yellow or ± white. Disk flower: 5–125; corolla yellow, puberulent, sometimes glandular, tube < throat, lobes deltate; anthers ± dark purple or yellow to ± brown, tips narrowly triangular or ± lanceolate to ovate; style branches awl-shaped, bristly. Fruit: generally 2–5 mm, generally club-shaped, black; ray fruit compressed front-to-back, ± curved, beakless, glabrous or sparsely hairy, pappus 0; disk fruit ± straight, generally ± hairy, pappus 0 or of 1–32 awns, scales, or bristles.
14 species: western North America. (George T. Lay, early 19th century English plant collector) [Baldwin et al. 2006 FNANM 21:262–269] Generally self-sterile (except Layia carnosa, Layia hieracioides, sometimes Layia chrysanthemoides).
Unabridged disk flower: anther bases obtuse to sagittate.
Unabridged references: [Baldwin 2006 Ann Missouri Bot Gard 93:64–93]

Key to Layia

1. Disk pappus 0

2. Plant glandless; paleae subtending ± all disk flowers ..... L. chrysanthemoides (2)

2' Plant glandular; paleae in 1 involucre-like series between ray and disk flowers

3. Plants apple- or banana-scented; basal rosette leaves generally minutely dentate to minutely serrate (coarsely toothed); ray corolla white or cream ..... L. heterotricha (2)

3' Plants unscented or not apple- or banana-scented; basal rosette leaves lobed; ray corolla white, yellow, or 2-colored, yellow proximally, distally ± white or pale yellow

4. Stem generally purple-streaked; involucre bell-shaped to hemispheric, ± spheric, or ± urn-shaped

5. Involucre ± spheric to bell-shaped or hemispheric; ray flowers 6–18 in 1 series, ray yellow throughout or distally white or pale-yellow ..... L. gaillardioides (2)

5' Involucre ± widely urn-shaped; ray flowers 13–27 in 2 series, ray 2-colored ..... L. jonesii (2)

4' Stem generally not purple-streaked; involucre ± hemispheric

6. Plant not strongly scented; ray yellow throughout or distally white; anthers generally ± dark purple, sometimes yellow to ± brown in Southwestern California ..... L. platyglossa (2)

6' Plant strongly lemon- or acrid-scented; ray white or yellow; anthers yellow to ± brown ..... L. pentachaeta (2)

7. Ray white ..... subsp. albida

7' Ray yellow ..... subsp. pentachaeta

1' Disk pappus of 1–32 awns, bristles, or scales

8. Heads discoid ..... L. discoidea

8' Heads radiate, ray sometimes inconspicuous

9. Paleae subtending ± all disk flowers; plant glandless

10. Disk pappus of generally very unequal, awl-shaped or bristle-like awns and scales ..... L. chrysanthemoides (2)

10' Disk pappus of ± equal, lanceolate scales ..... L. fremontii

9' Paleae in 1 involucre-like series between ray and disk flowers; plant glandular

11. Disk pappus of elliptic or lance-linear to ovate, non-plumose, non-woolly scales, 0.5–3.5 mm, bases sparsely bristly

12. Ray white; anthers yellow to ± brown; ray fruit sparsely hairy ..... L. leucopappa

12' Ray proximally yellow, distally white; anthers ± dark purple; ray fruit glabrous or sparsely hairy

13. Ray flowers 13–27 in 2 series; stem generally purple-streaked; pappus 0.5–2 mm; ray fruit shiny, glabrous; s Central Coast, c Outer South Coast Ranges ..... L. jonesii (2)

13' Ray flowers 6–15 in 1 series; stem not purple-streaked; pappus 2–3.5 mm; ray fruit ± dull, glabrous or sparsely hairy; s San Joaquin Valley ..... L. munzii

11' Disk pappus generally of bristles or bristle-like scales, 1–7 mm, if scales linear and long-tapering or awl-shaped, then proximally plumose and often proximally woolly adaxially

14. Disk pappus bristles or scales proximally plumose and adaxially woolly, or ± scabrous throughout, if proximally plumose and not woolly, then scales linear and long-tapering or awl-shaped; plant generally not strongly scented if not touched

15. Disk pappus of 10–15 linear and long-tapering or awl-shaped scales; ray generally ± white, sometimes pale or golden yellow ..... L. glandulosa

15' Disk pappus of (11)14–32 bristles or bristle-like scales; ray yellow throughout or distally white

16. Disk pappus generally scabrous throughout, sometimes proximally plumose and adaxially woolly in Southwestern California; ray yellow throughout or distally white; anthers generally ± dark purple, sometimes yellow to ± brown in Southwestern California; involucre ± hemispheric; phyllary tips often > folded bases ..... L. platyglossa (2)

16' Disk pappus densely plumose proximally and adaxially woolly; ray yellow; anthers yellow to ± brown; involucre narrower, bell-shaped to ± ellipsoid; phyllary tips generally < folded bases ..... L. septentrionalis

14' Disk pappus bristles or bristle-like scales proximally plumose, generally not woolly adaxially; plant generally strongly scented, even when not touched (except fleshy plants of coastal dunes)

17. Disk pappus readily falling as a unit; basal rosette leaves generally minutely dentate or minutely serrate (coarsely toothed); ray white or cream ..... L. heterotricha (2)

17' Disk pappus persistent; basal rosette leaves lobed; ray white or yellow throughout, or proximally yellow and distally white or pale yellow

18. Anthers yellow to ± brown ..... L. pentachaeta (2)

19. Ray white ..... subsp. albida

19' Ray yellow ..... subsp. pentachaeta

18' Anthers ± dark purple

20. Stem not purple-streaked; ray white, 1.5–3.5 mm; ray fruit sparsely hairy ..... L. carnosa

20' Stem purple-streaked; ray yellow throughout or distally ± white or pale yellow, 1–18 mm; ray fruit glabrous

21. Ray yellow throughout or distally ± white or pale-yellow, 3.5–18 mm; disk pappus of 15–24 bristles or bristle-like scales, main stem ascending, not strictly erect ..... L. gaillardioides (2)

21' Ray yellow, 1–4 mm; disk pappus of 10–16 bristles or bristle-like scales; main stem strictly erect ..... L. hieracioides

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Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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