# Manual of the New Zealand Flora/Euphorbiaceæ

Order LXXV. EUPHORBIACEÆ.
Herbs or shrubs or trees of exceedmgly various habit; juice milky, acrid. Leaves alternate, rarely opposite, often stipulate. Flowers usually small, unisexual (in Euphorbia reduced to single naked stamens surrounding a solitary pistil and enclosed within a ​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 1 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 order, of about 200 genera and 3000 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 (Euphorbia) has a worldwide 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 | 1. Euphorbia. |
| ** Flowers provided with a perianth. |
| Low-growing herbs. Flowers in terminal racemes or heads. Anthers opening by pores | 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 | 4. Homalanthus. |
1. EUPHORBIA, 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 worldwide distribution, very feebly represented in New Zealand. There are probably more than 600 species, of very diversified habit and characters. Several species from the Northern Hemisphere are naturalised in New Zealand, the most common being the milkweed, E. 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.
​1. E. glauca, Forst. Prodr. n. 208.—A tall stout perfectly glabrous smooth and glaucous herb 1–3 ft. high. Stems from a creeping rhizome, erect, terete, lower portion marked with the scars of the fallen leaves, leafy above, umbellately branched at the top. Leaves crowded, 1–4 in. long, linear- or lanceolate-obovate to oblong-obovate, obtuse or mucronate, sessile, quite entire. Umbels broad; rays 5–6, each once or twice forked; floral leaves much broader than the cauline, broadly oblong. Involucres almost concealed by the floral leaves, shortly pedicelled, campanulate, ¼ in. diam.; glands 4–5, dark-purple, crescent-shaped. Capsule nearly as large as a pea, pendulous, globose, quite smooth and glabrous. Seeds smooth, greyish.—A. Rich. Fl. Nouv. Zel. 352; A. Cunn. Precur. n. 339; Raoul, Choix, 42; Hook. f. Fl. Nov. Zel. i. 227; Handb. N.Z. Fl. 248.
North and South Islands: Common along the shores from the North Cape to the south of Otago. Waiuatua. October–February. Also found in Norfolk Island.
2. PORANTHERA, Rudge.
Annual or perennial herbs, sometimes woody at the base. Leaves narrow, alternate, stipulate. Flowers racemose or subumbellate at the tips of the branches, or solitary in the axils of the upper leaves, monœcious or diœcious. Male flowers: Calyx deeply divided into 5 segments imbricate in the bud. Petals 5, small, sometimes wanting; anthers 4-celled, cells free, opening by terminal pores. Rudimentary ovary of 3 clavate bodies. Female flowers: Calyx and petals of the males. Stamens wanting. Ovary broad, 3-celled; styles 3, each divided into 2 linear branches; ovules 2 in each cell. Capsule depressed, globose, splitting into 3 2-valved cocci. Seeds reticulate; embryo terete, curved, cotyledons not broader than the radicle.
A small genus of 6 species, 5 of which are Australian, 1 of them extending to New Zealand. The remaining species is endemic in New Zealand.
| Slender, diffusely branched. Leaves flat or nearly so. Flowers in terminal racemes | 1. P. microphylla. |
| Compactly branched. Leaves with the margins revolute to the middle. Flowers solitary in the upper axils | 2. P. alpina. |
1. P. microphylla, Brong. in Dup. Voy. Coq. Bot. 218, t. 50b.—A slender perfectly glabrous herb; branches diffuse, 6–9 in. long, prostrate at the base, ascending at the tips. Leaves opposite or alternate, ¼–½ in. long, linear-obovate or spathulate, obtuse, gradually narrowed into a rather long petiole; margins flat or very slightly recurved. Flowers minute, greenish-white, in terminal bracteate racemes; bracts linear-subulate, lower ones exceeding the flowers. Petals linear, usually present in both sexes. Capsule membranous, depressed. Seeds small, brown, granulate.—Benth. Fl. Austral. vi. 56; Cheesem. in Trans. N.Z. Inst. xi. (1879) 432.
South Island: Nelson—Fagus forest in the Maitai Valley, T.F.C., Kingsley! Marlborough—Pelorus and Tinline Valleys, abundant, Macmahon! December–February.
Widely distributed in Australia and Tasmania.
2. P. alpina, Cheesem. in Trans. N.Z. Inst. xiv. (1882) 300.—Perfectly glabrous, 2–5 in. high; branches numerous, decumbent or suberect, usually densely compacted and interlaced, rarely open, scarred, often somewhat woody at the base. Leaves all uniform, opposite, crowded, sessile or very shortly petiolate, ⅛–⅕ in. long, linear-oblong, obtuse, quite entire, smooth and veinless above; margins revolute, concealing the whole of the under-surface except the very thick and prominent midrib; stipules rather large, triangular. Flowers solitary in the axils of the upper leaves, forming short leafy heads, minute, greenish-white, dioecious; peduncles shorter than the leaves. Petals wanting in both sexes. Sepals 5, oblong, obtuse. Stamens shorter than the sepals; filaments slender. Ovary subglobose. 6-lobed, 3-celled. Capsule globose-depressed.—Hook. f. in Hook. Ic. Plant. t. 1366b.
South Island: Nelson—Mount Arthur, Mount Owen, T.F.C.; Mount Murchison, Townson! 3000–5000 ft. December–January.
3. ALEURITES, Forst.
Trees with stellate pubescence. Leaves alternate, petiolate, large, entire or 3–7-lobed. Flowers in terminal cymes, monœcious. Male flowers: Calyx splitting into 2–3 valvate segments. Petals 5, longer than the calyx. Stamens 8–20, on a central receptacle, 5 outer opposite the petals, alternating with 5 small glands; anthers adnate, cells parallel. Female flowers: Calyx and petals of the males. Ovary 2–5-celled; styles 2–5, bifid; ovules 1 in each cell. Fruit large, drupaceous; exocarp somewhat fleshy; endocarp 1–5-celled. Seeds large; testa thick, woody; cotyledons broad, flat.
A small genus of 3 species, natives of eastern Asia and the Pacific islands.
1. A. moluccana, Willd. Sp. Plant. iv. 590.—A handsome spreading tree 30–40 ft. high or more; young leaves and branches more or less clothed with pale or ferruginous stellate pubescence, almost glabrous when old. Leaves crowded towards the ends of the branches, 4–9 in. long, very variable in shape, ovate-lanceolate to broadly rhomboid-ovate, obtuse or acute, entire or 3–5- or 7-lobed. Cymes broad, much branched, tomentose; pedicels short. Flowers numerous, white. Calyx very small, tomentose. Petals about ¼ in. long, obovate, bearded at the base. Stamens 15–20; filaments short, hairy. Female flowers fewer and smaller than the males. Fruit 2 in. diam., smooth, fleshy; seeds 1–2, rarely 3; testa rugose.—Benth. Fl. Austral. vi. 128; Cheesem. in Trans. N.Z. Inst. xx. (1888) 172. A. triloba, Forst. Char. Gen. 112, t. 56.
Kermadec Islands: Sunday Island, not uncommon on the northern and eastern sides of the island, T.F.C. Candle-nut.
Widely distributed in the Pacific islands and tropical Asia, also extensively planted and naturalised in hot countries. The seeds or "nuts" contain an excellent oil, so that in many parts of Polynesia they are strung on sticks and used as candles, whence the English name of "candle-nut."
4. HOMALANTHUS, A. Juss.
Glabrous shrubs or small trees. Leaves alternate, petiolate, broad, entire, often glaucous; stipules deciduous. Flowers in terminal racemes, small, apetalous, monœcious. Male flowers: Very numerous, occupying all the upper portion of the raceme. Calyx of 1 or 2 minute flat appressed sepals. Stamens 6–50; filaments very short; anther-cells distinct, divaricate, longitudinally 2 - valved. Female flowers: Few or solitary at the base of the raceme. Calyx 2–3-partite. Ovary 2–3-celled; styles 2–3, linear, entire; ovules 1 in each cell. Capsule didymous or trigonous, fleshy, indehiscent or splitting into 2–3 2-valved cocci. Seeds with a fleshy aril.
Species 7–8, scattered through the Pacific islands, Australia, and the Malay Archipelago.
1. H. polyandrus, Cheesem.—A handsome slender tree 10–25 ft. high, everywhere perfectly glabrous; branches brittle, terete, marked with the prominent scars of the fallen leaves. Leaves in young plants 3–12 in. diam., in old much smaller, 2–4 in. long, broadly triangular-ovate or rhomboid-orbicular, acute, membranous, somewhat undulate, glaucous beneath; petiole as long or longer than the blade; stipules ¾ in. or more. Racemes slender, erect, 4–8 in. long. Male flowers: Very numerous, rather loosely placed, 1/12 in. diam.; bracts minute, 1–2-glandular at the base. Stamens about 40, very short, closely packed in a globose head. Female flowers: 1 to 4 at the base of the raceme, on long slender pedicels, drooping. Capsule ½–⅔ in., trigonous, 3-celled, splitting into 3 cocci. Seed enveloped in a yellowish aril, frequently persistent on the axis of the fruit.—H. nutans. Hook. f. in Journ. Linn. Soc. i. 127 (not of Guill.). Carumbium polyandrum, Hook. f. Handb. N.Z. Fl. 248; Cheesem. in Trans. N.Z. Inst. xx. (1888) 172.
Kermadec Islands: Sunday Island, plentiful; Macaulay Island, a few plants in the crater-basin, T.F.C. Flowers most of the year.
Endemic, but very closely allied to the Polynesian H. pedicellatus, Benth. (Carumbium nutans, Muell. Arg.), principally differing in the larger number of stamens.