Flora of New Zealand Series

hemp

Usually dioecious, sometimes monoecious herb. Stem angular, fibrous, densely hairy, 0.3-2-(5) m high. Lvs with (3)-5-9-(11) leaflets; seedling lvs and upper cauline lvs with fewer leaflets; leaflets acute to acuminate, attenuate at base, moderately hairy beneath, sparsely to moderately hairy above with globose-based hairs and some glandular hairs. Petiole < or = lf blade. Stipules 2 per node. Bracts triangular, hairy, green. Calyx of ♀ fls with simple patent hairs and numerous glandular hairs; calyx of ♂ fls with numerous, simple patent hairs and few glandular hairs. Achene ovate-ellipsoid, greyish brown or greenish, variously marbled cream or brown, 2.5-5 mm long.

Hemp seed was until recently a common constituent of bird seed and the plant often occurred as a casual from discarded seed. The sp. does not appear to have truly established in the wild but continues to occur as an occasional escape from cultivation.

N.: Opotiki District, Gisborne, Wellington City, Hutt Valley; S.: Christchurch, Banks Peninsula, S. Canterbury.

Probably C. Asia 1940

Gardens, waste places, cultivated land.

FL Jan-Apr.

C. sativa is extremely plastic in response to environmental conditions, as well as showing wide genetic variation throughout its worldwide distribution. Forms selected for cultivation are generally more robust and have larger seeds than those in the wild. Among cultivated plants there are many forms; 3 groups of forms reflect the 3 uses of the plant, for fibre, oil and resin production. Some authors go as far as recognising parts of this variation as separate spp., subspp., or vars - the 2 most commonly recognised being C. indica Lam. and C. ruderalis Janisch. Because all forms intergrade and none of the cultivated forms are very stable, and when the complicating factors of a long history of cultivation and environmental plasticity are taken into consideration, it seems best to treat Cannabis as a monotypic genus. A comprehensive treatment of the sp. problem is given by Small, E., The Species Problem in Cannabis (1979). The fibre has been used for rope making since 4000 B.C. and the resin has been used for medicinal purposes since at least 1000 B.C.