Art. XXXV.—On Ligusticum trifoliatum, Hook. f.
[Read before the Philosophical Institute of Canterbury, 22nd February, 1899.]
Regarding L. trifoliatum, Sir J. D. Hooker wrote: “A curious little species, at once known by the few petioled leaflets; it is probably 2-pinnate or 2 - ternately pinnate. I have only two specimens, and in the absence of fruit am not certain of its genus” (“Handbook of the New Zealand Flora,” p. 97). The late Mr. T. Kirk, F.L.S., urged me repeatedly to search for this plant, saying that it had never been found since its original discovery by Haast. I made repeated search in the habitats mentioned by Haast—“watercourses by the
Kowai River, altitude 2,000 ft.–3,000 ft,”—but was always unsuccessful, and it was not until last April that, while in company with Professor A. Dendy, I stumbled across the plant by the merest accident, growing not by the side of streams, but in Sphagnum swamps. Several living plants were secured; these have thriven, bloomed, and fruited under cultivation, and so I am enabled to publish an amended description. The point of interest is that, as Hooker hinted, the plant is not a Ligusticum, but an Angelica, and so the name must be changed to Angelica trifoliata.
A tufted low-growing marsh plant with spreading flowering branches, 6 cm. or 7 cm. high, and creeping underground stems.
Stem (portion above ground) very short or O, brown, covered with remains of old leaf-sheaths.
Leaves in very large specimens 7 cm. long, usually not more than half that length or smaller, trifoliate, pinnate or pinnate with ternate leaflets, with petioles as long as or longer than the rhachis; leaflets in one or two rather distant opposite pairs, simple or ternate, very variable in shape, showing many forms of transition from simple to compound leaves, rhombeo-orbicular, with cuneate base, flabelliform, cuneate or orbicular-cuneate, with upper usually rounded half of margin broadly serrate, sometimes trilobed, unequally bilobed or trifid, with cuneate base entire, coriaceous, green or brownish-green on upper surface, glaucous on under-surface; venation much reticulating, primary veins terminating in a small, swollen, pale apiculus at apex of each tooth; margins slightly recurved; petiolules semi-terete, channelled; from 6mm. to 2mm.; petioles semi-terete, narrow-channelled, sheathing base of flowering shoot and stem with a very broad sheath 4 mm. long, having broad pale-coloured membranous margin.
Umbels compound, 3- to 5-flowered, pedicels lengthening after flowering; with sheathing amplexicaul bracts similar in shape, &c., to the leaves but smaller, sometimes much reduced and linear.
Flowers 1.5 mm. to 2 mm. in diameter; calyx-limb very short, acute; petals white, emarginate at rounded apex or divided into two unequal lobes; styles 1mm. long, erect, spreading.
Fruit 4.5 mm. long × 3 mm. broad, oblong, dorsally compressed, with three prominent ribs on middle third, and two coriaceous lateral wings each 1.5 mm. broad.
Hab. Terrace of River Kowai, on right bank, altitude 690 m.; swampy ground, vicinity, of Porter's Pass, altitude 900 m.: amongst Sphagnum.
The plant bloomed in cultivation at end of December, the flowers being of very short duration, and the fruit ripe by middle of February. The leaves smell rather like carrot when bruised. The other Ligusticum, marked with a query in the Handbook, L. filifolium, should also, I think, be referred to Angelica.