Note on a New Species of New Zealand Champia.
[Read before the Auckland Institute, June 9, 1937; received by the Editor, August 9, 1937; issued separately, March, 1938.]
Champia Laingii sp. nov.
Fronde procumbente, ramis anastomantibus, sub-coalescentibus, in longitudinem 2–4 cm., ad substratum discis numerosis parvis affixis, regulariter articulata, vix ad genicula constricta, articulis aeque latis ac longis in partibus juvenilibus, in partibus-adultioribus sequi-longioribus. Ramulis, oppositis, alternates nonnunquam erectis, nunquam verticillatis aut dichotomis, fusiformis, ventricosis, frequenter ramulis tertiariis emittentibus, ramis et ramulis saepe arcuatis. Ramis juvenilibus teretibus ½–1 mm. latis, adultioribus compressis, expansis, ad basim constrictis, ad apicem attenuatis aut rotundatis, 1–2.5 mm. latis. Tetrasporis triangule divisis in cellulis corticalibus evolutis, in superficie inferiore solum. Cystocarpiis ?
Type-locality: The specimen chosen for the type of the species was found at the northern end of Long Beach, Russell, Bay of Islands, and has been deposited in the Herbarium of the War Memorial Museum in Auckland. The plant has also been reported from Purau (Lyttelton), Lyall Bay (Wellington), by R. M. Laing, to whom the species is dedicated.
Description of type: Plant procumbent, matted, generally epiphytic, fronds freely interattached, anastomosing, becoming a tangled mass of several layers, rooting repeatedly where fronds touch the substratum, holdfasts so formed small discs, stipitate; frond in young growths terete, ½–1 mm. wide, in older parts compressed, ellipsoid in section, tapering or constricted towards the base, and either attenuated or bluntly rounded at the tips; old fronds from 1–2 ½ mm. wide and up to 4 or more centimetres long; ramuli opposite, alternate, or growing here or there erect from the upper surface, but never from the under side; never verticillate or dichotomous, frequently of greater width than main frond, fusiform, ventricose, branches usually again branched, but further branching does not occur unless plant has attached itself by tip of frond or ramulus, when a new series of outgrowths commences; fronds and ramuli normally arched. Plant regularly articulated, lightly constricted at the joints, sometimes obviously so, articulations as broad as long in the young cylindrical growths, and from 2–3 times as broad as long in the older compressed parts; ends of damaged tips show
a dimple exposing the septum at the next constriction, but seldom, do regeneration tips occur. Fronds tubular, with a cortical layer of smallish, coloured, oblong or pyriform, vertical, assimilative cells; diaphragms composed of large, colourless, hexagonal cells, containing minute granules; hexagonal cells completely filling the tube in transverse section at the node; diaphragms connected by jointed, longitudinal filaments, one apparently passing through diaphragm after each third hexagonal cell, the number of the latter being the same (12–20) in both axes of the transverse section. Tetraspores in tetrads, scattered among the cortical cells, in the mature fronds and ramuli, sometimes in 4–5 transverse rows, on the under surface only, never on the upper iridescent surface; cystocarpic plants have not yet been found, although large quantities of material have been examined. Colour pinkish, but old growths generally light green mature growths which appear pink when dry show, in the fresh state, on the upper surface an iridescence of the most brilliant beetle-wing green, electric blue, or metallic purple, the iridescence appearing as minute specks, wanting at the nodes.
Champia Laingii seems to be an evanescent plant, frequently disappearing from a locality for long periods. It is to be found at or near low-water mark around the margins of shallow pools epiphytic upon the basal parts and sheltered by stunted Carpophyllum maschalocarpum, Xiphophora chondrophylla, occasionally on Zonaria Sinclairii, rarely amongst stunted Hormosira, Cladophora, and Corallina. It will also attach itself to fragments of shell, sand, rock, etc. The plant seems to prefer shallow pools or channels containing running water on more or less horizontal platforms over deep water at low-water mark; or if amongst Corallina a scarcely shelving sea-floor in exposed situations. In winter C. Laingii occurs in small, simple forms without much branching. In spring terete, longish growths arise which expand into normal fronds which in turn may become attenuated at the tips taking root whence new plants develop. Where broken the fronds exude gelose profusely.
Mr. Laing considers that this plant has previously been mistaken for, and recorded as, C. parvula Harv., the existence of which in New Zealand, however, he doubted as far back as 1902 (vide Laing, Revised List of New Zealand Seaweeds, Pt. II, Trans. N.Z. Inst., vol. 34). It differs from C. parvula, however, in the following points: Its widely expanded fronds, lack of verticillate branching, its more massive growth, less moniliform internodes, the lesser distance between articulations, the greater size of the tetrasporic ramuli bearing tetraspores on under surface only, and in the plant's being more or less prostrate and not bushy.
Champia Laingii sp. nov.
A. Habit sketch. × 1.
B(1). Trans. sect. of thallus at internode, showing cortical cells. Diagrammatic. × 6.
B(2). Trans. sect. of thallus at node, showing diaphragm. × 6.
C. Trans. sect. of thallus showing cortical cells. × 110.
D. Trans. sect. of thallus as at B(2). × 80.
E. Long. sect. showing two diaphragms and longitudinal filaments. × 50.
F. Portion of under side of tetrasporic thallus. × 2.
G. Trans. sect. showing tetrasporangia.
H. Long. sect. of apex of frond showing diaphragms and longitudinal filaments. Diagrammatic. × 5.
It is also evident that in the past C. Laingii has been mistaken for C. novae zelandiae. It is interesting to note that in his Presidential Address to the Phil. Inst. of Canterbury (vide Laing, On the Algae of New Zealand, Trans. N.Z. Inst., vol. 27, 1895) Laing speaks of the iridescence of C. novae zelandiae: “It may be worth while to put on record here that I have observed in C. novae zelandiae a remarkable iridescence, consisting chiefly of blue and green rays. When in the water the plant in this respect reminds one strongly of the brilliantly iridescent elytra of certain beetles. On removing the specimen from the water the iridescence to a large extent disappears, and there is not a sign of it after the plant has been dried.” Mr. Laing now agrees that these iridescent plants do not belong to the species novae zelandiae but represent the new species, C. Laingii.
I am greatly indebted to Mr. Laing for the great assistance he has given me in compiling this paper, and to Mrs. Perrin, of Tasmania, for Australian material for comparison.