Hectorella Hook.f.
Fls hermaphrodite, terminal on short lateral branches; two outer members variously interpreted as sepals or prophylls enclosing petaloid per. of 5 imbricate members; stamens 5, hypog., alternating with per. segs; filaments long and adnate to per. at base, anthers dorsifixed and extrorse; ovary unilocular, ovoid, narrowed into erect style with 2 triangular stigma lobes alternating with prophylls; ovules 4-5, on slender funicles, embryo curved. Fr. capsular but ind. Densely tufted glab. perennial cushion plants with entire lvs imbricated all round stem. Monotypic genus confined to N.Z.
Placed by Hooker in Portulacaceae. Ewart (J. Linn. Soc. (Bot.) 28, 1907) drew attention to the close relationship with Lyallia of Kerguelen Is, and suggested that Hectorella should be placed near it, in Caryophyllaceae. There it rests rather uneasily because (a) lvs are not strictly opp., (b) the status of the "prophylls" remains as unsatisfactory as that of the sepals in Portulacaceae; though their vascular supply comes off a little below that of the per. the tissues are fused and the relationship seems closer than between sepals and petals of, e.g., some spp. of Silene and Lychnis. Characters of pollen grains do not place the genus clearly in either family; sculpture has some features common to both Caryophyllaceae and Portulacaceae, but resemblance is more with the former; three long furrows in Hectorella contrast with 12-15 short furrows in Portulacaceae and no furrows, only pores, in Caryophyllaceae. Lyallia pollen does not seem to be known. (Pollen note contributed by W. F. Harris.) Mattfeld (Pflanzenfam. ed. 2, 16c, 1934, 367) places both Hectorella and Lyallia with the S. American cushion-plant genus Pycnophyllum in Tribe Pycnophylleae.
