Euphorbia. ] HUPHORBIACEAE. 541 
Family LVII. EUPHORBIACEAE. 
Herbs or shrubs or trees of exceedingly various habit; juice milky, 
acrid. Leaves alternate, rarely opposite, often stipulate. Flowers usually 
small, unisexual (in Huphorbia reduced to single naked stamens  sur- 
rounding a scolitary pistil and enclosed within a calyx-like involucre). 
Perianth generally simple and calycine, but often wanting, rarely double, 
the inner of 4-5 minute petals. Stamens 1 to many; anthers 2-celled. 
Ovary superior, of 3 (rarely 2 or more than 3) united carpels; styles as 
many as the carpels, free or united, entire or divided; ovules | or 2 to 
each carpel, pendulous from the inner angle of the cell. Fruit either a 
capsule of 2-valved 1—2-seeded cocci separating from a persistent axis, 
or a 1—3-celled drupe, or of 1 or more combined nuts. Seed laterally 
attached at or above the middle of the cell; embryo straight, in the axis 
of fleshy albumen, cotyledons flat, radicle superior. 
A large family, of about 230 genera and about 4000 species, most abundant in the 
tropics, rare in very cold climates. Many species are poisonous, and a considerable 
number yield medicinal products, as castor-oil, croton-oil, gum euphorbium, &c. Others 
afford a wholesome food, as the manioc and tapioca. Of the 4 genera found in New 
Zealand, one (Huphorbia) has a world-wide distribution ; another (Poranthera) is found 
elsewhere only in Australia. The two remaining (Aleurites and Homalanthus) have 
their headquarters in the Pacific islands, but extend northwards to China and the Malay 
Archipelago. 
* Flowers without a perianth, several males and one female in 
a cup-shaped calyx-like involucre .. Me 4 .. 1. EUPHORBIA. 
** Hlowers provided with a perianth. r 
Low-growing herbs. Flowers in terminal racemes or heads. 
Anthers opening by pores NS ry es .. 2. PORANTHERA. 
Trees with digitately lobed or veined leaves. Flowers in terminal 
cymes. Fruit large, somewhat fleshy, with 1-3 large oily seeds 3. ALEURITES. 
Trees. Flowers in slender racemes; males numerous, females 
few at the base of the raceme. Fruit capsular Jee w A Homananravs. 
1. EOPHORBIA Linn. 
Herbs or shrubs abounding in milky juice. Inflorescence of numerous 
males and a single female flower crowded in a small cup-shaped 4—5-lobed 
calyx-like involucre, the lobes usually alternating with as many fleshy 
glands, which often possess a white or coloured spreading limb. Male 
flowers consisting of a pedicelled stamen without floral envelopes of any 
kind; anther-cells globose. Female flower central in the involucre, of a - 
long-pedicelled 3-celled ovary, also without floral envelopes; styles 3; 
ovules solitary in each cell. Capsule 3-lobed, splitting into 3 2-valved 
cocci, which fall away from a persistent axis. 
A vast genus of world-wide distribution, very feebly represented in New Zealand. 
There are probably more than 750 species, of very diversified habit and characters. 
Several species from the Northern Hemisphere are naturalized in New Zealand, the 
most common being the milkweed, #. Peplus, a small glabrous annual branched from 
the base, with thin obovate entire leaves, an umbel of 2-3 repeatedly divided rays, 
smooth capsules, and pitted seeds. 
