Flora of New Zealand Series

Type locality: Wairau Mountains. Type: K, Travers.

Stems very stout, much and densely branched; plant forming close cushions up to ± 2 dm. diam.; branchlets densely villous with white or sordid-white hairs, axillary tufts conspicuous. Lvs very close-set, at first imbricate, sessile or nearly so. Lamina ± 4-7 × 1-4 mm., linear- to ovate-oblong, obtuse to subacute, subcoriac., equally densely villous on both surfaces or glabrate above; margins ciliate. Subfloral lvs us. broader. Infl. of 2-6 fls per head. Per. densely white-silky hairy, ± 4-5 mm. long; lobes ovate-oblong. Fr. ovoid, ± 2 mm. long, villous at apex, dark brown to black.

DIST.: S. Montane to subalpine grassland and fellfield from lat. 41° 30' to 45° 30', east of divide.

POLYMORPHY AND HYBRIDISM

Most spp. show a certain degree of diversity in size and form; this is especially marked in the contrast between the subfloral lvs and those lower on the branchlets. Often at the fall of the terminal infl. a pair of branchlets arise, leaving the persistent subfloral lvs.

Sexual expression has not been fully studied in any sp. Kirk (T.N.Z.I. 26, 1894, 259) sums up his observations: "As in all the New Zealand species with small leaves, the flowers of P. suteri are functionally dioecious, although apparently hermaphrodite. The staminate flowers may be distinguished at a glance by the greater length of the perianth; the erect anthers are distinctly exserted and produce abundance of pollen, while the short style, with its small abortive stigma, is invariably glabrous. In the pistillate plant the anthers are invariably abortive, and are hidden in the tube of the perianth; the large capitate stigma, thickly clothed with short papillose hairs, is prominent at the mouth of the tube, where it takes the place of the anthers in the proper staminate plant. My specimens do not show any instance in which the style in the proper staminate plant is bent on one side and protruded beyond the anthers, as is the case in the large-flowered forms of P. prostrata." Cheeseman (Man. N.Z. Fl. 1925, 578) dealing with the N.Z. spp. in general, says: ". . . all the New Zealand species are functionally dioecious, or occasionally polygamo-dioecious." His account of ♂ and ♀ is similar to that of Kirk, except that he points out that pollen is sts present in the ♀. Floral heteromorphy is illustrated in Ill. N.Z. Fl. 2, 1914, t. 172-175.

Cockayne and Allan (Ann. Bot., Lond. 48, 1934, 30) on field evidence considered that the following natural crosses were established: gnidia × longifolia (further attested by my observations in Fiordland), lyallii × prostrata (the coastal plants), pseudo-lyallii × prostrata (I have been unable to confirm this), prostrata × sericeo-villosa (not certainly established); more doubtfully they suggested arenaria × prostrata (collections by Mr. N. Potts at Opotiki, and myself at Foxton, show all the appearance of hybrid swarms), aridula × prostrata, buxifolia × prostrata (I have not myself seen evidence for this and the next), prostrata × traversii. There is some evidence for crosses of aridula with arenaria, concinna and tomentosa. The genus is not well-adapted for crossing experiments.

A somewhat diverse group of forms is at present included under this name. Hooker's description is: "A small, prostrate, much branched, densely tufted species, densely villous with whitish shining silky hairs; branchlets very short, leafy. Leaves close-set, 1/6-1/4 in. long, linear-oblong, obtuse, concave, equally villous above and below. Flowers few, densely silky, 1/6 in. long. Ovary villous with long hairs." The cushions are occ. laxer, and subalpine forms are often much reduced. Hybridism with P. pseudo-lyallii and P. aridula appears to play a part. Three forms are described: (a) BD 45485, tussock-grassland, Traveller's Valley, Tarndale, H. H. Allan 14/11/45. Plant very robust, branches up to ± 1 cm. diam.; branchlets crowded, clad in sordid-white, ascending hairs, especially at lf-axils. Lvs close-set, ± imbricated. Lamina elliptic to narrowly ovate-oblong, 4-6 × 2-3 mm., very soon glabrate above, clad in long ascending whitish hairs below; margins ciliate. Subfloral lvs slightly broader. Per. ± 4-5 mm. long, silky-hairy, white; lobes ± 1-1·5 mm. long, about ovate-oblong. A common Marlborough form.-(b) BD 68842, Grey's Hills, South Canterbury, A. P. Barker, 26/12/1949. Stems us. more slender, hardly attaining 7 mm. diam.; branchlets densely clad in long, pure-white ascending hairs, especially at lf-axils. Lvs close-set, imbricate. Lamina 2-3-(4) × 1-2-(3) mm., about ovate-oblong, obtuse, densely clad in white subappressed hairs below; upper surface less densely clad, slowly glabrate; margins us. ciliate. Subfloral lvs similar. Per. ± 4 mm. long, ± silky-hairy; lobes about oblong, ± 1 mm. long. A common form of the Mackenzie Basin.-(c) BD 64, western side of L. Wanaka, E. B. Levy, Sept. 1928. Stems rather stout; branchlets densely compacted, clad in sordid-white hairs, especially at lf-axils. Lvs close-set, imbricate. Lamina ± 4-6 × 1·5-2 mm., ovate to oblong-ovate, coriac., densely clad in subappressed sordid-white hairs below, slowly glabrate. Subfloral lvs broader. Per. c. 5 mm. long, densely clad in subappressed hairs; lobes c. 2 mm. long, ovate.

INCERTAE SEDIS

1. P. haastii Kirk in T.N.Z.I. 12, 1880, 396. "A strict low-growing shrub 6-10 inches high. Branches few (?), very slender, white with silky hairs. Leaves in distant pairs, petioled, ascending, narrow lanceolate, 3/4"-1/4" long, acute, hairy below or nearly glabrous, margins recurved; floral leaves similar. Flowers 5-8 in a head, very small, perianth swollen below, sessile, silky, lobes narrow, spreading; filaments short; style equalling the perianth tube. Fruit not seen. Hab.-South Island: Canterbury Alps-Professor von Haast, Mr. Armstrong."

Kirk remarks that P. haastii differs from P. virgata Vahl "in the distant, erect leaves, which are broader and less acute than in that well-known species." He thinks the specimens came from near Porter River.

The packet in W containing the type material contains (a) a slender twig devoid of lvs, densely clad in subappressed sordid-white hairs; (b) lvs of 2 forms-c. 25 × 7 mm., elliptic, subacute; c. 15 × 4 mm., narrow-ovate to elliptic, subacute; both forms with veins evident below, surface glab. except on prominent midrib below; (c) fls (separate) with tube c. 3 mm. long, clad in silky ascending hairs, lobes ovate. The lf-margins are slightly recurved.

2. P. polycephala Col. in T.N.Z.I. 22, 1890, 486. "Plant (apparently) a very small low densely-compacted shrub. Branches (specimens) small, stems thickish 1 in.-2 in. high . . . branchlets . . . 1/2 in.-3/4 in. long . . . hairs coarse, of unequal lengths, dirty-white. Leaves thickish, densely imbricated, small, sub-rhombic-orbicular, 1-11/2 lines diameter . . . Involucral leaves . . . larger, sub-orbicular . . . very membranous, reddish, much-veined . . . largely hairy on the whole of the under-surface; hairs white. Flowers not seen . . . but the floral leaves are clustered in several small heads (the size of a large pea) at the tips of the branchlets . . . Near the summit of Mount Ruapehu, in dry stony ground . . . 1889: Mr. H. Hill."

Cheeseman (Man. N.Z. Fl. 1906, 608) remarks "something of the appearance of a dwarf specimen of P. Traversii." The type specimens in W are too poor to make anything of, but possibly the abnormal floral lvs are due to insect-attack.

3. BD 72452, North Cape, M. C. Finlayson, 12/6/44. Branches ∞ from crown ± 10 mm. diam., crowded, erect, simple or branched towards tips, up to 2 dm. tall. Terminal portion of branches with dense tufts of white axillary hairs, bark dark brown. Lvs close-set, patent or deflexed, narrowed to sessile base. Lamina (5)-6-7-(8) mm., very coriac., deeply concave, glab., ± falcate, oblong-lanceolate, obtuse to subacute. I have seen only 1 specimen.

4. BD 59609, Waiau Gorge near Hanmer, in rocky crevices near marble quarry, A. J. Healy, 5/5/1946. "Forming dense ball-like shrub 0.75 m. tall." Branchlets, especially at axils, densely clad in sordid-white hairs. Lvs close-set, on short broad petioles. Lamina coriac., pale green, slightly concave, ovate to ovate-oblong, subacute, ± 5-7 × 3-4 mm.; ± silky-hairy on back when young. Infl. of few to several fls; per. ± 5 mm. long, densely silky-hairy, lobes ovate-oblong, ± 2 mm. long. Apparently related to P. concinna but lacking indumentum of lvs.

5. BD 54841, Haehae-te-moana R., Four Peaks Range, Canterbury, grassy hillside, R. Mason, 31/3/45. Branches slender, flexible, elongate, sprawling, ± dichotomously branched; bark reddish brown; branchlets very sparesely clad in long hairs. Lvs distant, internodes ± 10 mm. long; lamina (5)-7-10 × (2)-3-4 mm., subcoriac., oblong-lanceolate to elliptic, subacute to acute. Infl. of several fls; per. white, ± silky-hairy, ± 7 mm. long; lobes ovate-oblong, ± 2-3 mm. long. Similar specimens have been collected on Tasman Range, and the upper Rakaia.

There are, of course, numerous other forms that cannot well be referred to the described spp.