Part iv.—the Section Elatae Kukenthal

The following group of New Zealand endemic species is placed by Kukenthal (Pflanzenr. Heft 38, 1909) in the Sect. Pseudocypereae Tuckerm, but as stated when considering the Pseudocypereae (Hamlin, Trans. Roy. Soc. N.Z. 84: 683, 1957) there are important differences between that Section and the species under review. It is believed that these species are better placed with the Sect. Elatae Kukenthal, with which they agree in the large size, broad leaves, bracts long-sheathing, pedunculate spikes, long brown glumes, large strongly-nerved utricles with long beaks which are scabrid between the “crura” and with the mouth often oblique and the style base often flexuous. The term “crura” is used here, as in “Carices II and III” (Trans. Roy. Soc. N.Z. 84: 681–687, 1957) for the “teeth” at the apex of the utricle which are extensions of the lateral bundles beyond the orifice.

Kukenthal separates the Elatae and Echinochlaenae Holm from the Pseudocypereae in his key by the absence of transverse septa in the leaves of the two former sections and by the presence of them in the latter section. I haxe examined C. thouarsii Carm., C. insularis Carm., and C. laevigata Sm. (C. helodes Link), all placed in Elatae by Kukenthal, and find all three conspicuously septate-nodulose. This character is also present in some of the larger species of Sect. Echinochlaenae, as for example C. chathamica Petrie, C. longiculmis Petrie and C. dissita Boott in Hook. f.

C. kermadecensis and C. elingamita usually have the spikes compound—i e., smaller secondary spikes arise on the peduncle at the base of each main spike. This condition occurs commonly in only one other species of New Zealand sedge—namely, C. solandri Boott in Hook. f. of Sect. Echinochlaenae. In each of these cases the secondary spike arises in the axil of a glumiform bract, and the secondary peduncle is surrounded at the base by a cladoprophyll, usually utriculiform and different from the ochreiform cladoprophyll surrounding the base of the main peduncle. This is a similar condition to that which occurs in Subgenus Indocarex Baill. and is considered by Nelmes (Reinwardtia 3: 227, 1951) as indicating the origin of.

Subgenus Carex (Eucarex Coss. & Germ.) from Indocarex. He has suggested (l.c. p. 223) that the Elatae might be derived from Sect. Polystachyae of Indocarices; the occurrence of this indocaricoid character in species of Elatae, together with the relatively unspecialized organisation of the species of Elatae certainly appears to support this view. The Echinochlaenae, which will be reviewed in a later part of the present series, show an increasing complexity and diversity of organisation commensurate with an advance in evolution from the Elatae.

This view argues a relatively primitive status for the species under review, and I would place the Elatae as the most primitive section of Subgenus Carex in the New Zealand flora, followed by the secondarily-derived sections Echinochlaenae and Spirostachyae.

The view of the origin of the Elatae and Echinochlaenae from the Polystachyae is of geographic interest. The Polyatachyae (and most Indocarices) are chiefly Malavsian, being appreciably less abundant in tropical Africa and Australia, and entirely lacking in New Zealand. The Elatae on the other hand are chiefly African with one species, C. longebrachiata Boeck. (C. longifolia R. Br. non Tuckerm) approaching the New Zealand region in Australia. If the New Zealand section Echinochlaenae arose from the Elatae, then the absence of the latter from the New Zealand region, together with the absence of the former outside that region would give rise to a problem in distribution. The recognition of several New Zealand species as belonging to the Elatae removes this problem and at the same time strengthens the hypothesis of the affinity of the two sections, particularly as two species, C. cockayniana and C. elingamita, show definite relationships to species of Echinochlaenae, the former to C. solandri and C. dissita, and the latter to C. neesiana Endlich.

The position of the New Zealand species within the Section Elatae has not been investigated as a knowledge of all the species would be necessary. It appears, however, that, except for C. forsteri and C. cockayniana, the species are not closely related to each other, being distinguished by characters more conspicuous than those separating species of Echinochlaenae. This may, of course, be due to greater stability in a presumably older group.

The group is characterised by the following:—

Section Elatae Kukenthal, Pflanzenr. Heft 38. 645 1909; forest species, densely caespitose; basal sheaths aphyllous, brown or reddish, often with reticulate fibrils (“herringbone shaped”—Nelmes); leaves 0 5–1.2 cm wide, flat or slightly keeled, prominently 3-ribbed, septate-nodulose, usually longer than the culms; culms trigonous, usually smooth bracts leafy, long-sheathing; spikes pedunculate, often compound, stout or slender, terminal 1–4 male, remainder usually with male flowers at the base and/or apex; glumes brownish or reddish, acute or truncate or emarginate, awn up to 3 mm long; utricles membranous or subcoriaceous, nerved or costate, more or less stipitate, beak prominent, smooth or scabrid mouth oblique or straight, crura conspicuous (except in C. cockayniana) scabrid; nut trigonous, style straight or flexuous at the base, stigmas 3.

The following abbreviations (Index Herbariorum, Part I, Utrecht) are used for herbaria from which specimens have been seen:—AK, Auckland Institute and Museum; WELT, Dominion Museum, Wellington; CHR, Botany Division, D. S.I R., Christchurch; OTAGO, Botany Department, Otago University, Dunedin (not listed in the Index Herbariorum).