Flora of New Zealand Series

Usually monoecious, rarely dioecious annual or perennial herbs, shrubs or trees, sometimes succulent, with milky sap. Lvs present or O, stipulate or not, alternate or opposite, usually entire or serrate, rarely lobed. Cyathia solitary, clustered or umbellate; umbels or clusters axillary or terminal, simple or compound and often forming many times compound dichasia; rays and cyathia usually subtended by lvs. Fls lacking a perianth, grouped in cyathia consisting of a cup-shaped involucre with usually 4-5 petal-like glands; glands serrate, entire, or with 2 horns; cyathium usually with several ♂ fls each consisting of a single stamen jointed to a pedicel and often separated from each other by small bracteoles, and a single usually longer-pedicellate (rarely sessile) ♀ fl.; ovary usually 3-celled with a single ovule in each cell; styles usually 3, often 2-fid at tips. Fr. usually a 3-celled capsule separating at maturity from the persistent axis; seeds smooth or variously sculptured.

c. 2000 spp., tropical and temperate. Native sp. 1, naturalised 14.

Most of the spp. found in N.Z. are weeds in many regions of the world. Spurges can often be found flowering and fruiting at all times of the year. The shape of cyathial glands (Fig. 58) and sculpturing of the seed coat (Fig. 59) are important for identification. The milky sap may cause dermatitis (Connor 1977).

Fig. 58. Cyathia of Euphorbia. A E. helioscopia; B E. peplus. © All rights reserved. [Image: 4X5I]

Fig. 59. Seeds of Euphorbia. A E. exigua; B E. glauca; C E. helioscopia; D E. lathyris; E-F E. peplus (ventral and dorsal surface); G E. platyphyllos; H E. segetalis. © All rights reserved. [Image: 4X5J]