Flora of New Zealand Series

swan plant

Much-branched shrub to c. 2 m high, with slender puberulent stems. Lvs opposite or alternate, sessile or subsessile, 5.5-12 × 0.5-1 cm, linear-lanceolate, glabrous except for midrib beneath and sometimes scattered hairs above and on margins, sharply acute. Cymes axillary; fls few to fairly numerous. Peduncles and pedicels usually 1-2 cm long, densely puberulent. Calyx lobes 3.5-4 mm long, linear-lanceolate, densely puberulent. Corolla lobes 6-9 mm long, ovate-elliptic; margins white, ciliate towards apex at least on one side. Corona scales c. 4 mm long, fleshy, hooded, greenish white, incurved, with a lateral tooth or auricle on each side. Follicles 4-6 cm long, broad-ovoid, tapering to a beak, inflated, ± puberulent, covered with soft, subulate bristles 7-10 mm long.

N.: scattered localities throughout; S.: Nelson, Blenheim, Canterbury (Rangiora); K.: Raoul Id.

Southern Africa 1870

An escape from cultivation, waste places and abandoned gardens in and around settlements.

FL Dec-May.

The fl. and fr. are illustrated in Fig. 15. Swan plant is commonly cultivated in warmer parts of N.Z. to act as a host for monarch butterfly caterpillars. These insects normally extend southwards to Nelson and occasionally Marlborough and coastal N. Canterbury to Banks Peninsula (rarely stragglers occur inland and further south). The name Asclepias fruticosa L. is often applied to the swan plant and it was first recorded in N.Z. as A. nivea.

The very similar South and E. African G. physocarpus E. Meyer is now commonly grown in N.Z. as swan plant but has not yet been reported wild. It is most easily distinguished from G. fruticosus by the fresh frs, these being ± subglobose, much more inflated, and with a very short beak.