Species:
	Aciphylla dieffenbachii
Common Name(s):
	Dieffenbach’s speargrass, soft speargrass, coxella
Threat Status:
	Nationally Vulnerable
Status 2004:
	Nationally Vulnerable
Authority:
	Aciphylla dieffenbachii Kirk
Qualifiers:
	CD, EF, IE, RR
Family:
	Apiaceae
Flora Category:
	Vascular - Native
Synonyms:
	Gingidium dieffenbachii F.Muell., Ligusticum dieffenbachii Hook.f., Angelicia dieffenbachii Benth, et Hook.f., Coxella dieffenbachii (F.Muell.) Cheeseman et Hemsl.
Distribution:
	Endemic to the Chatham Islands where it is known from Chatham, Pitt, Mangere, Little Mangere, South East (Rangatira) islands and some of the Murumuru stacks and islets. It has also been deliberately introduced to Native Island and Ernest Islands off Stewart Island.
Habitat:
	Strictly coastal. Former habitat preferences unclear. Now only known from the Chatham (Rekohu) Island from steep, usually south facing, cliffs, rock scarps, ledges and colluvial slopes. It is usually found on basalt rather than schist rock substrates. On the outer islands, particularly those free of browsing animals it occupies similar habitats but can also be found in Poa chathamica Petrie swards, and amongst petrel burrowed ground.
Features:
	Tufted dioecious, perennial with extremely stout, napiform taproot. All parts exuding white, sticky latex when damaged. Leaves glaucous, flaccid, up to 0.7m long. Petiole, broadly sheathing near lamina junction furnished on either side by paper blunt lobes. Leaf lamina 150-400 x 100-300 mm. Primary pinnae 4-5(-7) pairs, segments up to 90 x 5 mm, linear, flaccid, apices bluntly mucronate. Inflorescence up to 1 x 0.6m diam., rather stout (almost woody). Umbels numerous, subpaniculately arranged. Peduncles rigidly stout, 50-150 mm long. Primary bracts pinnatisect with broad base. Male umbels up to 15 rays, 10 mm long, slender. Female umbels similar but with 3-6 rays. Involucral bracts linear-lanceolate, acuminate. Flowers golden-yellow. Male flowers with distinct triangular acute calyx-teeth; petals 2mm, oblong to ovate-oblong. Female calyx-teeth narrowly triangular, subacute; petals 1.5 mm, obovate. Fruit (schizocarp) 15 x 10 mm, golden yellow maturing grey, dorsally flattened, splitting at maturity into 2 more or less equal mericarps, these 2-3 winged, wings up to 3 mm wide.
Similar Taxa:
	One of only two species of Aciphylla on the Chatham Islands. A. dieffenbachii is a strictly coastal species which differs from A. traversii (F.Muell.) Hook.f. by the flaccid, more heavily divided, glaucous, blunt-tipped leaves, shorter (up to 1 m), fewer though much stouter and denser inflorescences with golden yellow flowers, and much larger fruits. By comparison A. traversii is a species of peat bogs, lake margins and peaty ground in open forest clearings. It has much larger, less flaccid and less divided dark green, sharply-tipped leaves, more numerous, taller (up to 1.8 m) distnctly narrower, more open inflorescences with cream-coloured flowers, and smaller fruits.
Flowering:
	November - February
Fruiting:
	January - June
Propagation Technique:
	Easy from fresh seed. Seed has short-term viability so will not store well. An attractive species ideal for a coastal situation. In good conditions spontaneous seedlings are often seen, and on occasion it can become invasive. It does best in full sun, with a moderately fertile to fertile, free draining soil. Does well in damp sand, frequently manured with sea weed. Plants should never be allowed to dry out, and even when well established are inclined to sudden collapse. This species often dies after a heavy flowering. Like most Chatham Island endemic plants this species dislikes humidity.
Threats:
	Domestic stock and feral mammals are the prime threats. Rodents probably eat seeds and seedlings; possums probably eat flowers and seedlings. The speargrass weevil (Hadramphus spinipennis) is dependent on the speargrass, but can be locally very damaging: adults eat stems, flowers and leaves; larvae eat roots as well. Thick exotic grass swards may inhibit seedling establishment.
Chromosome No.:
	2n = 22
Endemic Taxon:
	Yes
Endemic Genus:
	No
Endemic Family:
	No

Where To Buy
Can be purchased from Oratia Native Plant Nurseries (info@oratianatives.co.nz).

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Last updated: 18 Jan 2010