Flora of New Zealand Series

Infl. capitate or spicate; fls us. perfect, occ. unisexual. Cupule investing carpels, us. with 4 or more spines; sepals us. 4, petals 0; stamens us. few; carpels 1 or 2; stigmas plumose, ample. Herbs to semi-woody plants, us. prostrate, with ascending scapose flowering branchlets; lvs imparipinnate, stipules adnate. About 150, mainly southern hemisphere, spp. The N.Z. spp. all have capitate infl., and, if interpreted in a narrow sense, are endemic, though some forms are closely related to Australian ones.

No exact details have been worked out as to flowering and fruiting periods, but in general plants may be found in fl. 10-2, in fr. 12-4.

Bitter (Die Gatt. Acaena in Bibl. bot., Stuttgart 74, 1911) gives the following disposition of the N.Z. spp. as understood by him (all placed in his Reihe Terminales):

1. Sect. ANCISTRUM: Spines well-developed, us. with 4 retrorse, rigid, barbs at apex; achene 1 per cupule.

(a) Subsect. Laevigatae: Fls always perfect, stamens mostly 2, anthers purple, spines often > 4. A. saccaticupula.

(b) Subsect. Subantarcticae: Plants gynodioec., stamens 4, anthers purple, spines mostly 4. A. adscendens.

(c) Subsect. Euancistrum: Fls perfect; stamens 4, 3, or 2; anthers purple or white; spines mostly 4, barbed near apex.

(1) Ancistridium: Lflts ± glaucous on both surfaces, stamens 2, anthers purple, spines 4. A. fissistipula, A. hirsutula.

(2) Sanguisorbastrum: Lflts mostly green above, rarely glaucescent; stamens 2, anthers white; spines 4. A. sanguisorbae sens. ampl.

2. Sect. PTERACAENA: Cupule winged; spines short, not barbed, hidden by wings; plant glab. A. glabra.

3. Sect. MICROPHYLLAE: Achenes 2, rarely 1; spines 4, flexible, or 0; barb replaced by hairs or 0. A. buchananii, A. microphylla.