Flora of New Zealand Series

small-flowered nightshade

Unarmed annual or short-lived perennial herb, often bushy, up to 1 m tall, nearly always glabrous or almost so except when very young. Petioles to 5 cm long. Lamina very variable, in cauline lvs usually 4-10 × 1.5-5.5 cm (lvs at base of lateral shoots often smaller), ovate, ovate-oblong or lanceolate-ovate, entire to coarsely but distantly toothed or lobulate and sometimes with axillary leaflets; base broad-cuneate or attenuate; apex ± acute. Umbels few-flowered, with slender peduncles to c. 2 cm long at anthesis; pedicels becoming deflexed at fruiting. Calyx < 2 mm long, accrescent; lobes ovate to almost elliptic, usually strongly reflexed at fruiting. Corolla 5-8 mm diam., white or very pale mauve, glabrous; lobes ± triangular. Anthers 1-1.6 mm long. Berry 5-8 mm diam., globular, black, glossy; stone cells present. Seeds 1-2 mm long, broadly obovoid to almost orbicular.

N.: common on offshore islands in N. Auckland, Auckland and Bay of Plenty, also on the adjacent mainland, especially in remoter and less disturbed areas; S.: local in Nelson, Marlborough, Westland; K.: common.

Also indigenous to America, Africa, S.E. Asia, and the Pacific.

Scrub and open forest stands, cliffs, especially in dry coastal sites, sometimes rather moist gullies, occasionally a plantation weed.

FL Jan-Dec.

Possibly poisonous (Connor 1977), although also used as a pot herb.

S. americanum is presumed to be indigenous, although it may be an aboriginal introduction to the N.Z. region. Allan (1961) treated N.Z. plants as S. nodiflorum. The type of S. nodiflorum Jacq. is indistinguishable from S. americanum which is the earlier name (J. Edmonds, pers. comm.). N.Z. plants usually correspond to the fresh green form of Baylis, G. T. S., Trans. Roy. Soc. N.Z. 85: 379-385 (1958), described as subsp. nutans R. Henderson of S. nodiflorum (Henderson, R. J. F., Contributions from the Queensland Herbarium 16: 30 (1974)). This subsp. name should be transferred to S. americanum. This subsp. is fairly uniform and the only significant variation seen within the South Pacific region is a very hairy form which grows on the North and South Meyer Islets in the N. Kermadecs (Sykes 1977). Also plants in some southerly parts of its N.Z. range, especially those growing in very disturbed places, vary in having some mauve or purple colouration. It is possible that such plants represent an introduced element of what is a variable sp. in the New World, although this colour occurs in many Solanum spp. and probably only represents a single gene difference. S. americanum is now very widespread, but is probably at least indigenous to America, Australia and the Pacific region. The N.Z. subsp. is the usual or only infraspecific taxon present in the subtropical and tropical S. Pacific islands. S. americanum is often confused with S. nigrum, but in addition to the key characters the latter is hexaploid and nearly always lacks stone cells in the fr. and the former is diploid and has stone cells.