Jepson eFlora
Key to families | Table of families and genera

Key to Euphorbia

View taxon page for Euphorbia

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

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

1. Proximal leaves alternate, bases generally symmetric

2. Involucre gland appendage petal-like, white; shrub ..... E. misera

2' Involucre gland appendage 0; annual to perennial herb (E. dendroides a shrub)

3. Involucre glands 1–3, less often 4(5), ± cupped

4. Involucre, fruit densely hairy; seed oblong, flattened ..... E. eriantha

4' Involucre, fruit generally glabrous or ± so; seed ellipsoid to oblong or ovoid, not flattened

5. Bracts subtending cyathia each red proximally, green distally; stem glabrous ..... [E. cyathophora]

5' Bracts subtending cyathia each green or ± white proximally or throughout; stem hairy or glabrous

6. Hairs recurved on distal stems, abaxial leaf faces; seed >= 2.2 mm wide, coarsely tubercled ..... [E. davidii] (2)

6' Hairs ± straight, spreading on distal stems, abaxial leaf faces; seed <= 2.1 mm wide, finely tubercled ..... [E. dentata] (2)

3' Involucre glands 4(5), ± flat

7. Leaf margin finely to coarsely toothed

8. Leaf tip ± acute ..... E. terracina

8' Leaf tip rounded, obtuse, or notched

9. Perennial herb; stem densely hairy ..... E. oblongata

9' Annual; stem glabrous or sparsely hairy

10. Whorled inflorescence branches 5; fruit smooth; staminate flowers 8–15 ..... E. helioscopia

10' Whorled inflorescence branches 3; fruit tubercled especially near tip and on lobes; staminate flowers 5–10 ..... E. spathulata

7' Leaf margin generally entire (± entire to minutely crenate)

11. Shrub ..... E. dendroides

11' Annual to perennial herb

12. Annual (biennial)

13. Fruit lobes 2-keeled ..... E. peplus

13' Fruit lobes not keeled ..... E. crenulata

12' Perennial herb

14. Seed smooth

15. Seed ± white; leaves lanceolate ..... [E. rigida]

15' Seed gray to tan or ± brown; leaves linear to (ob)lanceolate ..... E. virgata

14' Seed rarely smooth

16. Seed with ± worm-like papillae (smooth), gray-brown; leaves obovate to ± round ..... [E. myrsinites]

16' Seed generally pitted or surface shallowly net-like, occasionally ± smooth; leaves elliptic to (ob)ovate or spoon-shaped

17. Leaf sessile; stem ascending to erect; gland shortly 2-horned, entire to scalloped between horns ..... E. lurida

17' Leaf ± sessile to short petioled; stem decumbent to erect; gland transversely obovate or fan-shaped, scalloped or incised but not 2-horned ..... E. schizoloba

1' Proximal leaves opposite

18. Leaves 4-ranked on proximal stem, bases symmetric; stems not forked, not 2-faced

19. Distal cauline leaves alternate

20. Hairs recurved on distal stems, abaxial leaf faces; seed >= 2.2 mm wide, coarsely tubercled ..... [E. davidii] (2)

20' Hairs ± straight on distal stems, abaxial leaf faces; seed <= 2.1 mm wide, finely tubercled ..... [E. dentata] (2)

19' Distal cauline leaves opposite or whorled

21. Glands of involucre transversely oblong, without horn-like lobes, white petal-like appendages present; leaves serrate; 1° inflorescence branches not whorled; fruit 2.5–3.4 mm ..... E. exstipulata var. exstipulata

21' Glands of involucre crescent-shaped, with 2 horn-like lobes, petal-like appendages 0; leaves entire; 1° inflorescence branches whorled; fruit 8–15 mm ..... E. lathyris

18' Leaves 2-ranked, bases generally asymmetric; stems repeatedly forked, 2-faced

22. Glands of involucre without white to pink or red petal-like appendages (appendages ± 0 on some glands in E. pediculifera)

23. Perennial herb

24. Fruit glabrous ..... E. parishii

24' Fruit hairy ..... E. pediculifera (3)

23' Annual

25. Fruit hairy

26. Involucre < 1 mm, glands << 0.5 mm; staminate flowers 2–5; fruit < 1.5 mm ..... E. micromera (2)

26' Involucre 1.5–2 mm, glands 0.5 mm; staminate flowers 22–25; fruit 2 mm ..... E. pediculifera (3)

25' Fruit glabrous

27. Leaf linear, base ± symmetric; stem proximally erect ..... E. revoluta (2)

27' Leaf oblong, lanceolate to (ob-)ovate to round, base asymmetric; stem prostrate to decumbent

28. Seed ± 2-angled, flattened, smooth; involucre glands transversely obovate ..... E. platysperma

28' Seed 3–4-angled, not flattened, smooth, wrinkled, or transversely ridged; involucre glands round or transversely elliptic

29. Fruit < 1.5 mm; seed 1–1.5 mm; staminate flowers 2–5 ..... E. micromera (2)

29' Fruit 2–2.5 mm; seed 1.5–2 mm; staminate flowers 40–60 ..... E. ocellata

30. Leaf <= 15 mm, lanceolate to ovate; Desert ..... subsp. arenicola

30' Leaf < 10 mm, ovate to sickle-shaped; California Floristic Province (except Peninsular Ranges) ..... subsp. ocellata

22' Glands of involucre with white to pink or red petal-like appendages (appendages ± 0 on some glands in E. pediculifera)

31. Cyathia generally in dense axillary cyme-like clusters, occasionally 1 per node; leaves 8–35 mm; stem generally ± erect (decumbent) ..... E. nutans

31' Cyathia 1 per node, occasionally dense on lateral branches or 1 at branch tips; leaves 1–40 mm; stem prostrate to ascending, occasionally erect

32. Fruit glabrous; stem, leaves, involucre generally glabrous (stem, leaves glabrous to hairy in E. abramsiana)

33. Stipules fused into wide, membranous scale

34. Perennial herb; fruit 2–2.5 mm; staminate flowers 15–30 ..... E. albomarginata

34' Annual; fruit ± 1.5 mm; staminate flowers 3–8(10) ..... E. serpens

33' Stipules free or fused, but not a wide, membranous scale

35. Perennial herb

36. Fruit, seed 2–2.5 mm; proximal stipules free ..... E. fendleri

36' Fruit, seed 1–1.5 mm; proximal stipules free or fused ..... E. polycarpa (2)

35' Annual

37. Leaves linear, base ± symmetric; stem prostrate to erect

38. Involucre glands 1–4, ovate, appendage narrower than gland; fruit, seed ± 2 mm; seed smooth; stem prostrate to ascending ..... E. parryi

38' Involucre glands ± 4, ± round, appendage wider than gland; fruit, seed <= 1.5 mm; seed transversely ridged; stem proximally erect ..... E. revoluta (2)

37' Leaves elliptic, oblong, lanceolate, ovate, round, or spoon-shaped, base asymmetric; stem prostrate to decumbent

39. Leaf margin entire ..... E. abramsiana (2)

39' Leaf margin toothed, at least toward tip, sometimes finely so

40. Styles simple; involucre gland appendages deeply 3–5-lobed ..... E. hooveri

40' Styles divided; involucre gland appendages entire, scalloped, or shallowly lobed

41. Stem subglabrous to hairy; seed transversely 4–6-ridged ..... E. abramsiana (2)

41' Stem glabrous; seed transversely 3–4-ridged or smooth to wrinkled

42. Seed transversely 3–4-ridged; involucre gland appendage wider than gland ..... E. glyptosperma

42' Seed smooth to wrinkled; involucre gland appendage narrower than gland ..... E. serpillifolia subsp. serpillifolia

32' Fruit with hairs, at least on lobes; stem, leaves, involucre generally with hairs

43. Perennial herb or shrub

44. Plant soft glandular-hairy with jointed hairs; staminate flowers 5–10; involucre urn-shaped – Sonoran Desert ..... E. arizonica

44' Plant puberulent to finely tomentose, strigose, or short-stiff-hairy with non-jointed hairs; staminate flowers >= 15; involucre urn- or bell-shaped or obconic

45. Seed 3-angled, ridged transversely ..... E. pediculifera (3)

45' Seed 0- or 4-angled (sometimes ± 3-angled in E. jaegeri), smooth to wrinkled or irregularly dimpled or faintly ridged transversely

46. Leaf hairs straight

47. Shrub; involucre gland appendage wider than gland, irregularly divided from halfway to ± base into 4–8 ± triangular to awl-shaped segments ..... E. jaegeri

47' Perennial herb; involucre gland appendage narrower to wider than gland, entire to scalloped ..... E. polycarpa (2)

46' Leaf hairs not straight

48. Involucre 1–1.5 mm; glands dark red to ± black ..... E. melanadenia

48' Involucre 2–2.5 mm; glands green to yellow or ± red ..... E. vallis-mortae

43' Annual

49. Involucre 1.5–2 mm; fruit 2–2.5 mm; staminate flowers 40–60 ..... E. ocellata subsp. rattanii

49' Involucre < 1.5 mm; fruit 1–2 mm; staminate flowers < 20

50. Involucre gland appendage deeply 3–5-lobed; involucre urn-shaped ..... E. setiloba

50' Involucre gland appendage entire to scalloped; involucre bell-shaped or obconic

51. Fruit 1.5–2 mm; seed wrinkled; involucre gland appendage narrower than gland ..... E. serpyllifolia subsp. hirtula

51' Fruit <= 1.5 mm; seed transversely ridged or wrinkled; involucre gland appendage as wide as to wider than gland

52. Seeds transversely wrinkled; fruit evenly strigose; involucre gland appendage as wide as gland ..... E. maculata

52' Seeds transversely ridged; fruit hairy only on lobes; involucre gland appendage as wide as to wider than gland ..... E. prostrata


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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