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Manual of the New Zealand Flora.
6. Zostera, Linn
6. Zostera, Linn.
Marine submerged plants. Rhizomes slender, branched, creeping and rooting at the nodes, often matted. Stems short, slender, leafy, compressed. Leaves distichous, alternate, narrow-linear, grass-like, 1–5-nerved, sheathing at the base; sheaths stipuliform with inflexed margins. Flowers monœcious, the males and females-placed alternately upon one face of a narrow spadix enclosed within the dilated membranous base of a leaf. Perianth wanting. Male flowers: Anther solitary, sessile, oblong, cylindric, curved, 1-celled dehiscence longitudinal; pollen confervoid. Female flowers: Carpel solitary, laterally attached above the middle, narrowed into a short subulate style; stigmas 2, capillary; ovule pendulous from the apex of the cell. Ripe carpel oblong, membranous, bursting irregularly. Seed pendulous; testa membranous, often striated; embryo large, deeply grooved, the linear incurved cotylecdonary end sunk in the groove.
Three or four closely allied species are known, found in shallow water on the shores of most temperate regions.
Leaves 3–9 in. x 1/16–1/10 in., truncate or notched at the tip. Spadix with transverse appendages, one folded over each carpel 1. Z. nana. Leaves 9–18 in. x 1/10–⅙ in., rounded at the tip 2. Z. tasmanica.
| 1. | Z. nana, Roth, Enum. Pl. Phœn. Germ. i. 8.—Rhizornes. slender, matted. Leaves 3–9 in. long, rarely more, 1/16–1/10 in. broad, narrow-linear, truncate or obscurely notched at the tip, with 3–5 faint parallel nerves on each side of the stout midrib and distant transverse veinlets, margins thickened. Floral sheaths or spathes ½–1 in. long, on peduncles of equal length, the blade of the leaf continued above the sheath, the sheath itself much wider than the blade. Spadix 6–12-flowered, its margins with transverse membranous appendages folded inwards, one over each carpel. Stigmas usually protruding through the slit of the spathe. Fruit about 1/10 in. long, oblong, obscurely striate.—Benth. Fl. Austral. vii. 176; Kirk in Trans. N.Z. Inst. x. (1878) 392. Z. Muelleri, Irmisch ex Aschers. in Linnœa, xxxv. (1867–68) 168,
North and South Islands, Stewart Island: Muddy and sandy shores, throughout, usually between high- and low-water marks. Widely distributed in temperate seas. |
| 2. | L. tasmanica, Martens ex Aschers. in Linnœa, xxxv. (1867–68) 168 (?).—Rhizornes slender, wide-creeping. Leaves 9–18 in. long, 1/10–⅙ in. broad, narrow-linear, rounded at the tip, not truncate, with 1–3 stout- nerves on each side of the midrib and several finer ones between, cross-veinlets distant. Flowers and fruit not seen.—Z. marina, Hook. f. Handb. N.Z. Fl. 742 (not of Linn.).
North and South Islands: Not uncommon in sandy or muddy places along the coasts, often in water of considerable depth. page 755The exact position of the New Zealand plant must remain doubtful until the fructification has been obtained, but it is probably the same as the Australian and Tasmanian Z. tasmanica, which seems hardly different from narrow-leaved forms of the northern Z. marina: |