Flora of New Zealand Series

PERSISTENT HORTICULTURAL OUTCASTS

The adventive flora of New Zealand includes a significant proportion of species of horticultural origin with differing status - casuals, established escapes, outcasts etc.

A number of herbaceous monocotyledonous perennials of Liliaceae, Amaryllidaceae and Iridaceae, constitute a distinct permanent, but only periodically apparent element in the vegetation of untended places - neglected cemeteries, grassy roadsides and waste land. These plants have the status of colourful persistent horticultural discards or outcasts; examples include species of Muscari, Scilla, Leucojum, Narcissus, Ixia and Sparaxis.

The colonies or clumps arise in the main from surplus bulbs, corms or rhizomes discarded from domestic gardens and dumped on untended land. In the absence of major soil disturbance of the habitat, colony increases is usually slow, the plants being non-aggressive and non-weedy. Increase is mainly by vegetative means, with spread by seed of little significance.

Evergreen or summer-green, with linear or lorate leaves, many species are not readily detected in the vegetative stage in grassy vegetative, and their occurrence is obvious only when the often tall scapes with showy flowers are produced.

In rural situations, colonies of such plants in grassland often mark the sites of now non-existent homesteads, while those on roadsides are sometimes relicts of ornamental plantings long ago; it is now difficult to determine with certainty, the origin of some such occurrences.

Fig. 8. Canna indica, Indian shot; flower of hybrid form (perianth and staminodia partly excised) showing petaloid stamen with 1-celled anther adnate to margin. © All rights reserved. [Image: 26XN]

Fig. 9. LILIACEAE. AMARYLLIDACEAE, IRIDACEAE; diagram of longitudinal section of A bulb, B corm (not found in Amaryllidaceae). © All rights reserved. [Image: 26XP]