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Vascular Plants of California
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Key to Lathyrus

View taxon page for Lathyrus

(For a list of species in Lathyrus, use the above link.)

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 often >= 2 mm wide ..... L. latifolius

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

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

4' Fruit glabrousleaflets  to widely , length 1.2–6.5 × width ..... L. tingitanus

2' Corolla 8–15 mm

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

5' Fruit glabrousinflorescence 1-flowered; calyx tube ± <= 

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

6' Inflorescence axis extended as bristle beyond flower; calyx tube ± <= 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. Leafletfruit gland-dotted; leaflets ± 14–16 – NCoR (Humboldt, n Mendocino cos.) ..... L. glandulosus

8' Leafletfruit not gland-dotted; leaflets often < 14

9. Stem with wings ± >= 1 mm wide

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

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

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

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

12. Plant generally ; KR, NCoR, CaR, n SN, GV, CW, SCoRO ..... var. californicus

12' Plant glabrous; GV (especially Solano Co., nearby CCo) ..... var. jepsonii

9' Stem with angles or flanges < 1 mm wide

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

14. Stipule ± >= ; generally dunes, beaches of immediate coast – NCo, n&c CCo

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

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

14' Stipule; not of immediate coast

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

17. Leaflets 10–15,  to , 1–2 cm; fruit  – NCo, NCoR, SnFrB ..... L. torreyi

17' Leaflets 4–8, generally  or narrowly  to fruit glabrous

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

18' Leaflets of at least some leaves 4–8, narrowly  to , 1.5–8 cm; corolla pale lavender to purple; KR, SNH, MP ..... L. lanszwertii var. aridus (2)

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

19. Stems , many, clustered; inflorescence densecorolla white to pink, 17–23 mm; MP (Modoc Co.) ..... L. rigidus

19' Stems  or sprawling, 1–few, clustered; inflorescence open or densecorolla lavender to pink-purple or, if white, < 17 mm; n CA-FP

20. Leaflets 10–16, subopposite to stipules in width often ± = leaflets; plant glabrous – KR, n&c NCoR ..... L. polyphyllus (3)

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

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

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

22. Corolla pale lavender to purple; KR, SNH, MP ..... var. aridus (2)

22' Corolla white to cream, banner often dark-striate; KR, NCoR ..... var. tracyi (2)

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

23. Leaflets ± = stipules, 6–8; coastal beaches, dunes – NCo (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  above middle; inflorescence 10–15-flowered, dense, generally 1-sided – flower appearing wide, blocky; KR, NCoR, SN ..... 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  or bent from middle or below; inflorescence 1–15-flowered, generally ± open (1-sided)

25. Corolla wine-red to crimson, 25–35 mm; banner  120–180° – s SCo, PR (San Diego Co.) ..... L. splendens

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

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

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

27. Stipules > 1 cm wide, leaflets 10–16, plants of KR, NCoR ..... L. polyphyllus (3)

27' Stipules < 1 cm wide and leaflets <= 12 or plants not of KR, NCoR

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

28' Inflorescence occasionally 2–16-flowered; not DMoj

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

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

30' Stem angled or ± flanged; stipules generally , < 0.5 mm wide; NW

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

31' Leaflets generally 8–12, glabrouscorolla 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 – KR, NCoR ..... 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 ; w CA-FP ..... L. vestitus

34. Corolla wine red to dark purple, 16–20 mm; banner generally  > 90°; SCo, s ChI, PR ..... var. alefeldii

34' Corolla pale lavender to purple, 14–18 mm; banner bent ± 90°; NCo, NCoR, CW, SW ..... 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,  or subopposite; especially KR, CaR, SN

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

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

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

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

 

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Citation for the whole project: Jepson Flora Project (eds.) . Jepson eFlora, http://ucjeps.berkeley.edu/eflora/ [accessed on ]

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

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