Flora of New Zealand Series

A. sanguisorbae Vahl var. antarctica Ckn. in T.N.Z.I. 36, 1904, 319.

A. sanguisorbae Vahl var. aucklandica Bitter in Bibl. bot., Stuttgart 74, 1911, 274.

A. sanguisorbae Vahl subsp. antarctica (Ckn.) Bitter in Fedde Repert. nov. Spec. Regn. veg. 10, 1912, 496.

A. anserinifolia (J. R. et G. Forst.) Druce var. antarctica (Ckn.) Druce in Rep. bot. (Soc.) Exch. Cl. Manchr. for 1916, 1917, 602.

Larger in all parts except heads; lvs up to 9·5 cm. long, upper lflts 18-20 mm. long, scapes 6-7 cm. long.

DIST.: A., C. Turfy and grassy places. Possibly only a luxuriant habitat-induced form.

HYBRIDISM

Buchanan (T.N.Z.I. 3, 1871, 208) recorded the occurrence of wild hybrids between the introduced Australian A. ovina and A. anserinifolia. Hybrids of this origin are common in the ∞ localities where these spp. meet. Swarms of the origin A. novae-zelandiae × ovina are also not uncommon. Rarely hybrids between A. ovina and A. microphylla are met with. Bitter (loc. cit. 1911, 297) found ∞ forms of hybrid acaenas in European botanic gardens, including the following between N.Z. spp.: anserinifolia × novae-zelandiae, glabra × novae-zelandiae, microphylla × novae-zelandiae, anserinifolia × microphylla. He also records hybrids between the above spp. and spp. of non-N.Z. or of uncertain provenance.

A preliminary list of wild hybrids occurring in N.Z. was given by Cockayne and Allan (Ann. Bot., Lond. 48, 1934, 24). The following groups are known, some forming complex swarms: A. anserinifolia, in one or other of its vars, with caesiiglauca var. pilosa, inermis, microphylla, novae-zelandiae (the crossing of anserinifolia and novae-zelandiae often produces very complex swarms). Hybrid swarms between buchananii and microphylla, inermis and microphylla, are also of frequent occurrence. The whole Microphyllae group is as yet very unsatisfactorily delimited. A dune sp., possibly A. depressa of Kirk, at Foveaux Strait, hybridizes freely with A. novae-zelandiae. A. caesiiglauca var. pilosa occ. meets A. glabra, and hybrid forms have been recorded.

No controlled breeding work has as yet been reported in N.Z., but seeds gathered from reputed wild hybrids have thrown diverse progeny, supporting the strong field evidence.

Bitter, loc. cit. 1911, 251, adopts the name A. sanguisorbae Vahl, amplifying the circumscription to include a number of Australian and N.Z. forms, grouped into subspp. His subspp. for the N.Z. mainland key down as follows:

1 Mature spines 7-10 mm. long, purple; lflts 11-13novae-zelandiae

Mature spines up to 6 mm. long, not purple; lflts not more than 112

2 Lflts green to brownish green above, paler below; lvs not > 3·5 cm. longpusilla

Lflts blue-green on both surfaces, or if on lower surface only then subglaucous-green above; lvs up to 10 cm. long3

3 Lflts blue-green on both surfaces; stipules simple or unidentatecaesiiglauca

Lflts subglaucous-green above, ashy glaucous below; stipules deeply 5-6-fldprofundeincisa

While the close relationships of these groups is undoubted, and fertile hybrids between them are ± common, yet in the absence of hybridism they are true-breeding. A narrower view of species limits is taken here, but tribute may be paid to the excellent analysis made by Bitter of the material he had at hand. Subsp. profundeincisa was described from garden material and has not certainly been met with in the field. Yet in all but the lf colour Bitter's description matches well the common form here ascribed to A. anserinifolia.