4.
Psilotum, Swartz.
Rhizome short, creeping, branched; true roots wanting. Stem erect or pendulous, simple below, repeatedly dichotomously branched above; branches angled or flat. Leaves very minute, scale-like, laxly placed, trifarious or distichous. Sporangia (or synangia), coriaceous, almost globular, usually 3-lobed and 3-celled, rarely 2-or 4-celled, in the axil or attached below the fork of a minute bifid scale-like fertile leaf or sporophyll, which is either sessile or raised on a short petiole. Spores minute, oblong, curved.
A small genus of two species, widely distributed in the tropical and subtropical regions of both hemispheres. The New Zealand species bas the range of the genus.
1. |
P. triquetrum,
Swartz, Syn. Fil. 117.—Stems 4–18 in. long, erect or pendulous when growing on trees, stout or slender, simple below, many times dichotomously branched in the upper part; branchlets triquetrous, the ultimate ones ⅓5–½0 diam. Leaves placed on the angles of the stems and branches, distant, minute, scale-like, ovate - subulate, 1½–⅛ in. long. Fertile leaves bifid, rather smaller than the foliage-leaves, sessile or shortly petiolate. Synangia 1/1;0–1/1;5 in. diam., globose or broader than long.—
Hook. Gen.
Fil. t. 87;
Fil. Exot. t. 63;
Hook. f. Fl. Nov. Zel. ii. 56;
Handb. N.Z. Fl. 391;
Benth. Fl. Austral. vii. 681; Bak.
Fern Allies, 30;
Thoms.
N.Z. Ferns, 108. P. heterocarpum,
Col. in Trans. N.Z. Inst. xx. (1888) 237.
Kermadec Island: Not uncommon,
T. F. C. North Island: Rangaunu Harbour,
R. H. Matthews! Rangitoto Island,
Colenso! and many others; Auckland Isthmus, very rare,
T. F. C.; Motuhora Island (Bay of Plenty),
Joliffe; near Maketu,
Kirk; soil heated by hot springs at Orakeikorako,
Kirk! Wairakei,
C. J.
Norton! and Tokaanu,
T. F. C. Sea-level to 1800 ft.
In all tropical and subtropical regions as far north as Japan and Florida.
|