Art. LIV.—On the Occurrence of a Variety of Mitrasacme montana, Hook. f., in New Zealand.
[Read before the Wellington Philosophical Society, 12th June, 1889.]
The herbaceous genus Mitrasacme comprises about thirty species, twenty-seven of which are found in Australia, two or three in tropical Asia, and a single endemic species discovered by Mr. J. Buchanan, F.L.S., on the mountains above Dusky Bay. The discovery of a strongly-marked variety of an Australian species in New Zealand is therefore of considerable interest. Some time back I received specimens from Mr. R. Helms, late of Greymouth, which at first sight bore a close resemblance to Mitrasacme montana, Hook, f., but presented sufficient points of difference to render them worthy of varietal rank. I propose to distinguish this form as var. helmsii. The stems are more imbricating, matted, and more depressed than in the type. It may be characterized as under:—
Mitrasacme montana, Hook, f., var. helmsii.
A small herbaceous perennial, forming depressed matted patches. Stems slender, 1½in.–2in. high; leaves opposite, obovate, glabrous, narrowed into very short flattened petioles, or sessile. Flowers invariably terminal, nearly sessile; calyx 4-partite, segments linear, shorter than the corolla, acute or obtuse, persistent in fruit; corolla tubular, slightly contracted at the mouth, lobes short, acute; ovary rounded, styles erect, connivent, slender. Capsule small, nearly or quite sessile, mouth compressed, the outer angles produced into lateral curved filiform processes.
Hab. South Island—Paparoa Ranges, Westland; 3,000ft. R. Helms.
This differs from the typical form in the more ‘densely matted habit, the longer calyx, in the peduncles being absent, or never elongated even in fruit, and in having the compressed fruits produced into curved lateral filiform processes. The flowers are of a delicate fawn colour.
The typical form occurs in Tasmania and Victoria.
Explanation Of Plate XXXII.
Mitrasacme montana, Hook. f., var. helmsii.
Fig. 1. Flowering specimen, natural size.
Fig. 2. Leaves, enlarged.
Fig. 3. Flower, enlarged.
Fig. 4. Calyx, enlarged.
Fig. 5. Corolla, enlarged.
Fig. 6. Corolla laid open to show the stamens, enlarged.
Fig. 7. Pistil, enlarged.
Fig. 8. Fruit, natural size.
Fig. 9. " enlarged.