Euphorbia L.

7. Euphorbia L. View in CoL View at ENA 1

Monoecious. Herbs or small shrubs, with latex. Flowers in small groups surrounded by a more or less deeply lobed involucre with 4-5 (rarely more) glands at the top and usually pubescent within, the whole forming a cyathium. ‘Inflorescence’ of cyathia usually umbellate, often with axillary rays below the umbel. Perianth absent. Male flowers of a single stamen jointed to the pedicel. Female flowers solitary, pedicellate, surrounded by several male flowers; ovary 3-locular, with 3, usually free, styles; ovules solitary in each loculus. Seeds usually carunculate.

In the following account the inflorescence is referred to as an umbel, though it is not strictly one. The leaves subtending the primary branches (rays) of the umbel are called ray-leaves and those subtending the ultimate branches raylet-leaves. The bracts, when present, subtend the individual male flowers in the cyathium.

In addition to the species described below several others are reported as casual aliens in S. Europe, and some o f them may be in process of naturalization. These include E. indica Lam. , Encycl. Méth. Bot. 2: 423 (1788), E. missurica Rafin. , Atl. Journ. 1:146 (1832), E. engelmannii Boiss. , Cent. Euphorb. 15 (1860) and E. rhytisperma (Klotzsch & Garcke) Engelm. ex Boiss. in DC., Prodr. 15(2): 43 (1862).

E. marginata Pursh , Fl. Amer. Sept. 2: 607 (1814), from North America, is cultivated for ornament and frequently escapes in S.E. Europe. It is an annual with the ray- and raylet-leaves with wide, petal-like, white margins and the glands with conspicuous white appendages.

Literature: E. Boissier in DC., Prodr. 15(2): 7-187 (1862).

1 Stipules present; leaves usually asymmetrical at the base, opposite, but not decussate

2 Ripe seeds smooth 3 Leaves linear-oblong 3. polygonifolia

3 Leaves ovate or falcate-oblong

4 Seeds 3 mm 2. peplis

4 Seeds less than 1*5 mm 4. humifusa

2 Ripe seeds rugulose 5 Capsule hairy

6 Capsule hairy on the keels only 7. prostrata

6 Capsule hairy all over

7 Hairs on capsule closely appressed 6. maculata

7 Hairs on capsule patent 5. chamaesyce

5 Capsule glabrous

8 Leaves 10-30(-36) mm, serrate 1. nutans

8 Leaves (1—)3—7(—11) mm, entire or obscurely serrulate

5. chamaesyce

1 Stipules absent; leaves symmetrical at the base, usually alternate 9 Leaves opposite and decussate; capsule spongy 60. lathyris 9 Leaves alternate, rarely opposite but then not decussate; capsule indurate

10 Glands suborbicular or ovate, sometimes irregularly lobed,

but neither homed nor with the outer margin truncate or emarginate

11 Shrubs with stout branches; glands suborbicular, entire or irregularly lobed

12 Leaves 25-65 mm, glabrous; capsule smooth or nearly so

9. dendroides 12 Leaves c. 150 mm, sparsely hairy beneath; capsule verrucose 8. stygiana 11 Herbs, or slender, wiry dwarf shrubs; glands ovate, entire

13 Annual or biennial; stems usually solitary

14 Capsule winged 54. pterococca 14 Capsule not winged

15 Capsule tuberculate

16 Tubercles in 2 rows on each valve of the capsule; seeds verruculose 53. cuneifolia 16 Tubercles not in 2 rows on each valve of the capsule; seeds smooth

17 Tubercles ending in a long bristle; capsule usually indéhiscent 17. akenocarpa 17 Tubercles not ending in a bristle; capsule dehiscent

18 Lowest raylet-leaves like the ray-leaves; capsule not more than 2-5 mm; seeds reddish 51. serrulata 18 Lowest raylet-leaves markedly different from the ray-leaves; capsule 2-3 mm; seeds olive-brown

50. platyphyllos 15 Capsule not tuberculate

19 Seeds reticulate-rugose or transversely sulcate

20 Leaves entire; seeds with 3 transverse depressions on each face 56. phymatosperma 20 Leaves serrate in the upper half; seeds reticulaterugose 55. helioscopia 19 Seeds smooth

21 Capsule glabrous, even when young

22 Capsule indéhiscent, scarcely sulcate 17. akenocarpa 22 Capsule dehiscent, usually distinctly sulcate

23 Leaves entire or weakly sinuate; umbel with 3 rays; capsule 5-7 mm 14. lagascae 23 Leaves sharply serrate; umbel with 4-5 rays; capsule c. 3 mm 15. arguta 21 Capsule hairy, at least when young

24 Leaves rounded and mucronulate at apex; capsule

3-4 mm, persistently sericeous or with scattered bristles 17. akenocarpa 24 Leaves, except the lowest, acute; capsule c. 2-5 mm, pubescent when young, becoming glabrous

16. microsphaera 13 Perennial herbs or small shrubs; stems usually numerous

25 Capsule smooth or nearly so

26 Stems slender, not scaly below 13. corallioides 26 Stems stout, scaly below

27 Rhizome without tubers; raylet-leaves longer than wide; seeds not more than 3-2 mm 12. villosa 27 Rhizome with large tubers; raylet-leaves wider than long; seeds c. 4 mm 11. isatidifolia 25 Capsule tuberculate or cristate

28 Seeds minutely tuberculate 52. pubescens 28 Seeds quite smooth, rarely shallowly vermiculate-rugose

29 Procumbent or ascending; inflorescence usually reduced to a single cyathium, rarely with 2-3 short rays

30 Stems not scaly at base; glands 8 49. capitolata 30 Stems scaly at base; glands 4 48. chamaebuxus 29 Erect; inflorescence always of several cyathia

31 Plant with a large, subterranean, napiform tuber; stems usually less than 20 cm 31. apios 31 Plant without a large, subterranean tuber; stems more than 20 cm

32 Capsule with 2 crests on the back of each carpel

23. gregersenii

32 Capsulenotcristate

33 Shrubs with slender stems

34 Rays of the umbel anddeadtwigs persistent

35 Rays of the umbel spinescent; cauline leaves and ray-leaves similar 47. acanthothamnos

35 Rays of the umbel not spinescent; ray-leaves much wider than the cauline 45. spinosa

34 Rays of the umbel and dead twigs not persistent

36 Leaves mucronate; ray-leaves rhombic- or orbicular-ovate, mucronate 44. squamigera

36 Leaves not mucronate; raylet-leaves ovate or obovate, not mucronate

37 Capsule with long, slender tubercles 46. glabriflora

37 Capsule with low, broad tubercles 43. bivonae

33 Herbs, sometimes woody at base

38 Tubercles on capsule ± hemispherical

39 Umbel with more than 5 rays 18. palustris

39 Umbel with 1-5 rays

40 Stems scaly at base

41 Raylet-leaves ovate-lanceolate or elliptical; cyathium long-pedunculate; capsule with small, hemispherical tubercles 36. carniolica

41 Raylet-leaves broadly rhombic; cyathium

± sessile; capsule with large, irregular tubercles 37. duvalii

40 Stems not scaly at base

42 Plant nearly or quite glabrous

43 Leaves acuminate

44 Axillary rays not overtopping the umbel; raylet-leaves 1C—17 mm; capsule deeply sulcate 19. velenovskyi

44 Axillaryrays overtoppingthe umbel; rayletleaves 4-10 mm; capsule scarcely sulcate

20. soongarica

43 Leaves obtuse, rarely acute

45 At least the lower leaves widest above the middle

46 Ray-leaves much shorter than the rays;

rays long, patent 42. clementei

46 Ray-leaves about as long as the rays, at least at flowering time; rays short, crowded 38. brittingeri

45 All leaves widest at or below the middle

47 Middle cauline leaves linear-lanceolate, acute; capsule 5-7 mm 39. ruscincnensis

47 Middle cauline leaves broadly ovate to ovate-lanceolate, obtuse or subobtuse; capsule 3-5-4 mm

48 Leaves 10-30 mm; ray-leaves broadly ovate to suborbicular 40. welwitschii 48 Leaves 50-80 mm; ray-leaves narrowly rhombic 41. monchiquensis

42 Plant distinctly pubescent

49 Capsule sparsely tuberculate 30. oblongata

49 Capsule densely tuberculate 38. brittingeri

38 Some of the tubercles on capsule at least twice as long as wide, often filiform

50 Stems scaly at base

51 Rhizome swollen and jointed; stems c. 2 mm in diameter; raylet-leaves triangular

52 Stems terete 34. dulcis

52 Stems finely ribbed in upper part 35. angulata

51 Rhizome cylindrical; stems c. 5 mm in diameter; raylet-leaves ovate 12. villosa

50 Stems not scaly at base

53 Leaves distinctly serrate or serrulate

54 Stems stout; ray-leaves orbicular

(25-29). epithymoides group

54 Stems very slender; ray-leaves ovate to obovate

55 Leaves linear-oblong; ray-leaves obovatecuneate 33. uliginosa 55 Leaves obovate to obovate-oblong; rayleaves ovate

56 Upper leaves acute or subacute; all leaves about equal in size 38. brittingeri 56 Upper leaves rounded at apex; lower leaves much smaller than upper 32. polygalifolia 53 Leaves entire or almost entire

57 Plant glabrous

58 Ray-leaves obovate or suborbicular

(25-29). epithymoides group 58 Ray-leaves ovate

59 Stems 70-150 cm, stout, erect; axillary rays numerous 21. ceratocarpa 59 Stems 5-30 cm, slender, decumbent; axillary rays absent 32. polygalifolia 57 Plant pubescent

60 Leaves glabrousabove; tubercles on capsule usually mixed long and short, the long not tapering 22. byberna 60 Leaves ±hairy above; tubercles on capsule all long, tapering, purple-tipped

61 Upper leaves acute; raylet-leaves reniform-deltate 24. squamosa 61 All leaves obtuse; raylet-leaves elliptical to ovate (25-29). epithymoides group 10 Glands homed or with a truncate or emarginate outer margin

62 Homs of glands short, oftendilatedandminutelylobedat apex; bracts between the male flowers absent

63 Leaves obovate to suborbicular 57. myrsinites 63 Leaves lanceolate

64 Leaves lanceolate; seeds smooth 58. rigida 64 Leaves linear-lanceolate; seeds rugose-vermiculate

59. brotcri 62 Homs of glands usually slender, or outer margin of glands truncate or emarginate; bracts between the male and female flowers present, hirsute or plumose (except 86)

65 Annual; seeds not smooth

66 Seeds tuberculate or rugulose

67 Lower leaves narrowly linear, very numerous and usually closely imbricate 61. aleppica 67 Lower leaves not narrowly linear and closely imbricate

68 Seeds vermiculate rugulose

69 Seeds oblong, black, sometimes with white ridges

62. medicaginea 69 Seeds ovoid, brown or grey

70 Leaves linear to linear-oblanceolate 64. exigua 70 Leaves obovate 67. peplus 68 Seeds tuberculate

71 Capsule 2-5 x 2-8 mm 63. dracunculoides 71 Capsule 1 -6-2 x 1 -6 mm 64. exigua 66 Seeds pitted or sulcate or both

72 Seeds sulcate, sometimes also pitted

73 Seeds sulcate and pitted; capsule with 2 ridges on each valve 67. peplus 73 Seeds sulcate, not pitted; capsule not ridged

74 Seeds transversely sulcate 65. falcata 74 Seeds longitudinally sulcate 66. sulcata 72 Seeds pitted, but not sulcate

75 Raylet-leaves linear 68. ledebourii 75 Raylet-leaves rhombic-trullate to transversely ovate

76 Raylet-leaves obliquely rhombic-trullate

69. taurinensis 76 Raylet-leaves rhombic-deltate to transversely ovate

70. segetalis 65 Perennial; seeds smooth or not

77 Seeds pitted, rugulose or tuberculate

78 Procumbent or ascending; umbel not developed or with not more than 3 rays

79 Capsule not winged 90. maresii 79 Capsule winged 91. hemiariifolia 78 Erect; umbel usually with more than 3 rays

80 Seeds tuberculate 93. pithyusa

80 Seedsrugulose orpitted

81 Seeds rugulose; axillary rays aggregated to form a whorl below the umbel 77. biumbellata 81 Seeds pitted; axillary rays not aggregated into a whorl below the umbel

82 At least some leaves serrate; teeth slender

10. serrata 82 Leaves entire, or serrulate towards the apex

83 Capsule at least 4 mm wide; raylet-leaves lanceolate to ovate

84 Ray-leaves little shorter than cauline leaves; cyathial lobes very densely ciliate

78. boetica 84 Ray-leaves distinctly shorter than cauline leaves; cyathial lobes sparsely ciliate 79. bupleuroides 83 Capsule not more than 3-5 mm wide; raylet-leaves reniform, deltate, rhombic, transversely ovate or suborbicular

85 Glands truncate 80. nicaeensis 85 Glands with (1—)2 horns

86 Glands with short horns; seeds irregularly or shallowly pitted

87 Seeds evenly and shallowly pitted 74. petrophila 87 Seeds irregularly pitted 75. transtagana 86 Glands with long horns; seeds evenly and fairly deeply pitted

88 Leaves linear-lanceolate, acute 71. pinea 88 Leaves obovate to oblanceolate, usually obtuse and mucronate

89 Seeds less than 2 mm 72. portlandica 89 Seeds more than 2 mm 73. deflexa 'll Seeds smooth

90 Raylet-leavesusually connatein pairsatbase; capsule glabrous or pubescent; stems usually flowering in the second year

91 Capsuledenselyvillous 105. characias 91 Capsule glabrous

92 Axillary rays arranged in 2-5 whorls below the umbel 104. beldreichii 92 Axillary rays not in whorls 103. amygdaloides 90 Raylet-leaves not connate; capsule glabrous; stems usually flowering in the first year

93 Capsule 4-6 mm wide

94 Up to 15 cm, withhorizontal rhizome (Greece) 82. orphanidis 94 Up to 70 cm, withvertical stock (widespread)

95 At least some leaves sharply serrate 10. serrata 95 All leaves entire or minutely serrulate

96 Glands with long horns; caruncle prominent, boat-shaped; leaves imbricate and succulent

102. terracina 96 Glandsemarginate,withshorthorns; caruncle minute, conical; leaves imbricate, ± succulent

97 Leaves obovate-oblong to ovate; rays 3-6 94. paralias 97 Leaves linear-oblong to linear-oblanceolate; rays 8-12 79. bupleuroides 93 Capsule not more than 4-5 mm wide

98 Leaves palmately veined, somewhat coriaceous, often glaucous

99 Leaves obviously irregularly and sharply serrulate near the apex 93. pithyusa 99 Leaves nearly or quite entire

100 Umbel with (5-)7-20(-30) rays

101 Umbel with not more than 8 rays

102 Leaves (10-)40-75mm 80. nicaeensis 102 Leaves not more than 20 mm 89. gayi 101 Umbel with up to 30 rays

103 Leaves usually acute; seeds 1 -5-2 mm

92. seguierana 103 Leaves usually obtuse; seeds 2-2-5 mm

80. nicaeensis 100 Umbel with (1—)2—5(—9) rays 104 Leaves 17-27 mm wide, prominently 9- to 11- veined 81. bessarabica 104 Leaves not more than 17 mm wide, with fewer than 9 weak veins 105 Ray-leaves longer than the cauline leaves 88. variabilis 105 Ray-leaves not longer than the cauline leaves 106 Plant with basal rosette of leaves 107 Rosette-leaves oblanceolate, usually obtuse; axillary rays 0-4(-7) 84. triflora 107 Rosette-leaves linear-oblanceolate, usually emarginate; axillary rays 0(—1) 85. saxatilis 106 Plant not forming rosettes 108 Glands 2-homed 109 Homs shorter than the gland 110 All leaves less than 6 mm wide 76. matritensis 110 Some leaves more than 6 mm wide 83. barrelieri 109 Homs at least as long as the gland 111 Leaves entire 84. triflora 111 Leaves finely serrulate 83. barrelieri 108 Glands truncate or crescentic 112 Leaves usually more than 10 mm wide 80. nicaeensis 112 Leaves less than 10 mm wide 113 Cyathial cup glabrous within 86. valliniana 113 Cyathial cup pubescent within 114 Capsule 3-3-5 mm 87. minuta 114 Capsule 2-5 mm 89. gayi 98 Leaves pinnately veined, usually membranous and not glaucous 115 Leaves cordate at base 116 Stems up to 25 cm; leaves not more than 30 mm 95. nevadensis 116 Stems up to 90 cm; leaves up to 80 mm 96. agraria 115 Leaves rarely cordate at base 117 Plant puberulent or pubescent 118 Leaves lanceolate to ovate-lanceolate; umbel with up to 16 rays 98. salicifolia 118 Leaves linear to linear-lanceolate; umbel with up to 6 rays 99. esula 117 Plant glabrous 119 Leaves usually emarginate or 3-cuspidate 120 Leaves linear 99. esula 120 Leaves oblanceolate to elliptic-obovate 121 Not rhizomatous; leaf-margins flat 99. esula 121 Rhizomatous; leaf-margins undulate 100. undulata 119 Leaves not emarginate or 3-cuspidate 122 Upper surface of leaves shiny 97. lucida 122 Upper surface of leaves dull 123 Leaves linear, crowded, especially on the lateral shoots 101. cyparissias 123 Leaves lanceolate to broadly ovate, not crowded 99. esula