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Manual of the New Zealand Flora.
1. Isoetes, Linn
1. Isoetes, Linn.
Characters of the order.
Widely distributed in most temperate and tropical regions. Over 60 species are admitted in the most recent enumeration, but many of them are very imperfectly known. The two found in New Zealand are endemic.
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Macrospores tubercled 1.I. Kirkii. Macrospores smooth 2, I. alpinus.
| 1. | I. Kirkii, A. Braun in Berl. Monatber., July, 1869.—Permanently submerged. Stem short, tuberous, deeply 3-lobed; roots numerous. Leaves 10–30, very slender, 3–12 in. long, about ½0 in. diam., tapering to a fine point, pale-green, diaphanous, usually with a few stomata, but with no accessory bast-bundles. Sporangia rather small, broadly oblong or almost globose, about ⅛ in. long; indusium complete. Macrospores rather small, chalky-white, beset all over with small unequal tubercles. Microspores very minute, trigonous, most minutely punctate.—Kirk in Trans. N.Z. Inst. ii. (1870) 107, t. 7; Bak. Fern Allies, 127; Thoms. N.Z. Ferns, 109.
North Island: Wairua River, A. Thompson! lakes in the Middle Waikato Basin, abundant, Kirk! T. F. C.; Lake Rotokakahi, Kirk! Lake Taupo, G. J. Norton! South Island: Small lakes near Lake Tekapo, T. F. C. Sea-level to 2500 ft. Best distinguished from the following species by its smaller size and more slender habit, fewer leaves, and particularly by the conspicuously tubercled macrospores. |
| 2. | I. alpinus, T. Kirk in Trans. N.Z. Inst. vii. (1875) 377, t. 25.—Permanently submerged; much larger and stouter than I. Kirkii. Stem stout, deeply 3-lobed. Leaves very numerous, 50–70, 6–18 in. long or even more, 1/1;5–1/1;0 broad at the middle, much dilated at the base, gradually tapering to the apex, dark-green, diaphanous, usually with a few stomata, but with no accessory bast-bundles. Sporangia oblong, ⅙–⅕ in. long; indusium complete. Macrospores greyish-white, smooth or very indistinctly tubercled. —Bak. Fern Allies, 127; Thoms. N.Z. Ferns, 109. (?)I. multiangularis, Col. in Trans. N.Z. Inst. xxii. (1890) 449.
North Island: Lake Taupo, C. J. Norton. South Island: Not uncommon in lakes in mountain districts, from Nelson to the south of Otago. 1200–3000 ft. |