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Manual of the New Zealand Flora.
1. Azolla, Linn
1. Azolla, Linn.
Floating water-plants. Stems copiously pinnately branched, emitting on the under-side numerous rootlets. Leaves densely imbricating, very minute, sessile, deeply and unequally 2-lobed. Sporocarps or conceptacles in pairs in the axils of the leaves on the under-surface of the stem, of two kinds: one kind larger, globose, enclosing numerous microsporangia, each of which contains numerous microspores arranged in separate groups or massulæ furnished with a membranous envelope; the other smaller, ovoid, containing a single macrosporangium within which is a solitary macrospore. Macrospores each crowned with few or many swimming-floats; massulse of the microspores armed with simple or hooked bristles.
A small genus of 4 or 5 species, found in most tropical or warm temperate regions.
| 1. | A. rabra, R. Br. Prodr. 167. — Floating, red or reddish-green, often gregarious and covering large sheets of water; the separate plants ½-l in. long, orbicular or ovate or somewhat deltoid, copiously bipinnate. Leaves densely imbricating, about ½0 in. long, 2-lobed, the lobes ovate, obtuse. Larger sporocarps globose, about ½0 in. diam.; the massulse of the microspores armed with copious hooked bristles. Smaller sporocarps hardly more than half the size, oblong; the solitary macrospore crowned with 3 swimming-floats. — Hook. f. Fl. Nov. Zel. ii. 56; Handb. N.Z. Fl. 392; Benth. Fl. Austral. vii. 680; Bak. Fern Allies, 137.
North and South Islands, Stewart Island: Abundant in still waters throughout. Also found in Australia and Tasmania, and very closely allied to the South American A. filiculoides, Lam., of which some authors consider it to be a variety. |