Manual of the New Zealand Flora/Marsileaceæ
Order XCIV. MARSILEACEÆ.
Perennial plants, usually of small size, growing in marshes or in damp soil. Rhizome slender, creeping, rooting at the nodes. Leaves solitary or in tufts at the nodes of the rhizome, either filiform or of 4 leaflets borne at the top of a slender petiole. Sporecarps or conceptacles globose or oblong, on short peduncles which rise from the petioles or near their bases, each sporocarp containing numerous (Marsilea) or few (Pilularia) cavities or cells, and each cell containing a group or sorus composed of macrosporangia and microsporangia. Macrosporangia containing a single macrospore; microsporangia containing numerous microspores.
A small order of 2 genera and 50 or 60 species, found in most temperate and tropical countries. In germination a small female prothallium is developed within the macrospore, which eventually bursts, the prothallium protruding from the opening. A single archegonium is then formed on the prothallium, which is fertilised by spermatozoids set free by the bursting of the microspores, within which a rudimentary male prothallium bearing a single antheridium has been developed.
1. PILULARIA, Linn.
Rhizome long, filiform, creeping and rooting. Leaves solitary at the nodes of the rhizome, circinate in vernation, filiform, erect. Sporocarps on short peduncles, globose, 2–4-celled, splitting at the top into as many valves as cells; each cell with a longitudinal parietal placenta bearing in the upper portion microsporangia containing numerous microspores, and below these few or many macrosporangia containing a solitary macrospore.
A small genus of 6 species, found in the temperate or subtropical regions of both hemispheres. The New Zealand species is endemic.
1. P. novæ-zealandiæ, T. Kirk in Trans. N.Z. Inst. ix. (1877) 547, t. 29.—Very slender. Leaves distant, ¾–2 in. long. Peduncle about ¼ in. long, erect. Sporocarp ⅙ in. diam., globose, densely hairy, 2-celled and 2-valved. Macrosporangia 10–12 to each cell, subglobose, not constricted at the middle.—Thoms. N.Z. Ferns, 100; Bak. Fern Allies, 148.
North Island: Auckland—Lake Whangape, Kirk. South Island: Canterbury—Lake Lyndon, Lake Pearson, and other lakes in the Waimakariri district. Kirk! Enys! Berggren, T.F.C.
Probably not an uncommon plant, but very easily overlooked.