Jepson eFlora
Key to families | Table of families and genera

Key to Lathyrus

View taxon page for Lathyrus

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Leaflets 2; generally of disturbed habitats

2. Corolla 20–30 mm

3. Inflorescence 4–15-flowered; wings of stem, petiole often >= 2 mm wide ..... L. latifolius

3' Inflorescence 2–4-flowered; wings of stem, petiole < 2 mm wide

4. Fruit hairy; leaflets ovate to narrowly elliptic, length 1.2–3 × width ..... L. odoratus

4' Fruit glabrous; leaflets lanceolate to widely ovate, length 1.2–6.5 × width ..... L. tingitanus

2' Corolla 8–15 mm

5. Fruit hairy; inflorescence 1–2-flowered; calyx tube ± = lobes ..... L. hirsutus

5' Fruit glabrous; inflorescence 1-flowered; calyx tube ± <= lobes

6. Inflorescence axis not extended beyond flower; calyx tube << lobes; corolla red-purple ..... L. cicera

6' Inflorescence axis extended as bristle beyond flower; calyx tube ± <= lobes; corolla not red-purple

7. Peduncle 2–8 cm; corolla lavender or purple; fruit veins indistinct, netted ..... L. angulatus

7' Peduncle 0.5–2 cm; corolla orange-red; fruit veins distinct, longitudinal ..... L. sphaericus

1' Leaflets 2–16, > 2 at least on some leaves; generally of natural habitats

8. Leaflet, fruit gland-dotted; leaflets ± 14–16 — North Coast Ranges (Humboldt, n Mendocino cos.) ..... L. glandulosus

8' Leaflet, fruit not gland-dotted; leaflets often < 14

9. Stem with wings ± >= 1 mm wide

10. Leaflets (4)6(8), opposite; immediate coast, n North Coast ..... L. palustris (2)

10' Leaflets generally 8–16, irregularly arranged; immediate coast only in n Central Coast

11. Corolla 10–15 mm, white, generally lavender-striate, fading yellow-tan; nw Klamath Ranges (Del Norte, w Siskiyou cos.) ..... L. delnorticus (2)

11' Corolla 15–20 mm, generally pink to pink-purple ..... L. jepsonii

12. Plant generally puberulent; Klamath Ranges, North Coast Ranges, Cascade Range, n Sierra Nevada, Great Central Valley, Central Western California, Outer South Coast Ranges ..... var. californicus

12' Plant glabrous; Great Central Valley (especially Solano Co., nearby Central Coast) ..... var. jepsonii

9' Stem with angles or flanges < 1 mm wide

13. Tendrils not coiled or branched, often a short bristle

14. Stipule ± >= leaflet; generally dunes, beaches of immediate coast — North Coast, n&c Central Coast

15. Plant glabrous or puberulent; leaflet 2.5–4.5 cm ..... L. japonicus (2)

15' Plant gray-hairy; leaflet 1–2 cm ..... L. littoralis

14' Stipule < leaflet; not of immediate coast

16. Inflorescence 1–2-flowered; leaflet generally 0.5–2 cm; fruit glabrous or puberulent

17. Leaflets 10–15, elliptic to ovate, 1–2 cm; fruit puberulent — North Coast, North Coast Ranges, San Francisco Bay Area ..... L. torreyi

17' Leaflets 4–8, generally oblong or narrowly lanceolate to linear; fruit glabrous

18. Leaflets 4, lance-oblong, generally 0.5–1(2) cm; corolla green-white, dark-striate; High North Coast Ranges (Red Mtn, Humboldt Co.) ..... L. biflorus

18' Leaflets of at least some leaves 4–8, narrowly lanceolate to linear, 1.5–8 cm; corolla pale lavender to purple; Klamath Ranges, High Sierra Nevada, Modoc Plateau ..... L. lanszwertii var. aridus (2)

16' Inflorescence 2–16-flowered; leaflet 1–8 cm; fruit glabrous

19. Stems erect, many, clustered; inflorescence dense; corolla white to pink, 17–23 mm; Modoc Plateau (Modoc Co.) ..... L. rigidus

19' Stems erect or sprawling, 1–few, clustered; inflorescence open or dense; corolla lavender to pink-purple or, if white, < 17 mm; n California Floristic Province

20. Leaflets 10–16, subopposite to alternate; stipules in width often ± = leaflets; plant glabrous — Klamath Ranges, n&c North Coast Ranges ..... L. polyphyllus (3)

20' Leaflets 4–10, irregularly arranged or opposite; stipules in width generally ± <= leaflets; plant often hairy

21. Corolla 13–25 mm; leaflets generally elliptic or widely ovate, generally opposite ..... L. nevadensis var. nevadensis (2)

21' Corolla 7–12 mm; leaflets generally linear to lanceolate, irregularly arranged or opposite ..... L. lanszwertii

22. Corolla pale lavender to purple; Klamath Ranges, High Sierra Nevada, Modoc Plateau ..... var. aridus (2)

22' Corolla white to cream, banner often dark-striate; Klamath Ranges, North Coast Ranges ..... var. tracyi (2)

13' Tendrils, at least on some leaves, coiled and generally branched

23. Leaflets ± = stipules, 6–8; coastal beaches, dunes — North Coast (Del Norte, Humboldt cos.) ..... L. japonicus (2)

23' Leaflets generally > stipules, 6–8 or not; generally inland

24. Corolla white-yellow to bronze-orange (drying tan or dark), 11–14 mm; banner reflexed above middle; inflorescence 10–15-flowered, dense, generally 1-sided — flower appearing wide, blocky; Klamath Ranges, North Coast Ranges, Sierra Nevada ..... L. sulphureus

24' Corolla not white-yellow (except Lathyrus lanszwertii var. tracyi) to bronze-orange (occasionally fading tan-yellow), 11–14 mm or not; banner reflexed or bent from middle or below; inflorescence 1–15-flowered, generally ± open (1-sided)

25. Corolla wine-red to crimson, 25–35 mm; banner reflexed 120–180° — s South Coast, Peninsular Ranges (San Diego Co.) ..... L. splendens

25' Corolla white to purple, 8–25 mm; banner bent ± 90°

26. Leaflets (4)6(8), opposite, glabrous or ± puberulent, flowers 3–6 per inflorescence, 15–20 mm; immediate coast, n North Coast ..... L. palustris (2)

26' Leaflets, flowers not entirely as above; immediate coast only in n Central Coast

27. Stipules > 1 cm wide, leaflets 10–16, plants of Klamath Ranges, North Coast Ranges ..... L. polyphyllus (3)

27' Stipules < 1 cm wide and leaflets <= 12 or plants not of Klamath Ranges, North Coast Ranges

28. Inflorescence generally 2-flowered; ne Mojave Desert (Grapevine Mtns, Inyo Co.) ..... L. hitchcockianus

28' Inflorescence occasionally 2–16-flowered; not Mojave Desert

29. Corolla white or cream, fading yellow-tan (occasionally to lavender in Lathyrus vestitus var. ochropetalus) — Northwestern California

30. Stem flanged or narrowly winged; stipules widely triangular, 0.5–0.8 cm wide; nw Klamath Ranges (Del Norte, w Siskiyou cos.) ..... L. delnorticus (2)

30' Stem angled or ± flanged; stipules generally lanceolate, < 0.5 mm wide; Northwestern California

31. Leaflets generally 4–6, glabrous or puberulent; corolla 9–12 mm ..... L. lanszwertii var. tracyi (2)

31' Leaflets generally 8–12, glabrous; corolla 14–16 mm ..... L. vestitus var. ochropetalus

29' Corolla purple, lavender, or ± red (occasionally to white in Lathyrus nevadensis var. nevadensis)

32. Stipules > 1 cm wide; leaflets 10–16 — Klamath Ranges, North Coast Ranges ..... L. polyphyllus (3)

32' Stipules < 1 cm wide; leaflets 4–12

33. Flowers often crowded, generally 8–14, corolla 14–20 mm; leaflets 8–12, generally subopposite to alternate; w California Floristic Province ..... L. vestitus

34. Corolla wine red to dark purple, 16–20 mm; banner generally reflexed > 90°; South Coast, s Channel Islands, Peninsular Ranges ..... var. alefeldii

34' Corolla pale lavender to purple, 14–18 mm; banner bent ± 90°; North Coast, North Coast Ranges, Central Western California, Southwestern California ..... var. vestitus

33' Flowers generally spaced, either 2–10 and corollas 8–16 mm or 2–4 and corollas 13–25 mm; leaflets 4–10, opposite or subopposite; especially Klamath Ranges, Cascade Range, Sierra Nevada

35. Leaflets generally opposite, generally elliptic or widely ovate; inflorescence 2–4-flowered; corolla 13–25 mm ..... L. nevadensis var. nevadensis (2)

35' Leaflets generally subopposite or irregularly arranged, ovate to linear; inflorescence 2–10-flowered; corolla 8–16 mm

36. Stipules widely ovate-triangular, often toothed, conspicuous; calyx glabrous except lobes often finely ciliate; corolla generally 10–14 mm, banner upcurved above other petals ..... L. brownii

36' Stipules lanceolate, not toothed, often inconspicuous; calyx generally hairy; corolla 10–16 mm, banner generally more reflexed than other petals ..... L. lanszwertii var. lanszwertii


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
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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