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Manual of the New Zealand Flora.
7. Dicksonia, L'Herit
7. Dicksonia, L'Herit.
Usually tree-ferns, but in some species the caudex is short or absent. Fronds large, 2–3-pinnate. Stipes smooth or muricate Veins pinnately forked, veinlets always free. Sori near the margin of the frond, globose, placed on the apex of a veinlet receptacle more or less elevated. Indusium distinctly 2-valved the upper valve continuous with the margin of the frond and usually similar to it in texture, consisting of an incurved or concave lobule; lower valve membranous or coriaceous. Sporangia numerous' sessile or nearly so, bursting transversely; ring oblique, complete.
page 953Excluding the section Patania (Dennstœdtia,Bernh.), which seems to be more appropriately placed in the vicinity of Davallia, the genus contains about 25 species, widely dispersed through the tropical and subtropical regions of both hemispheres. The 3 New Zealand species are endemic, but one of them differs-but slightly from the Australian D. antarctica,Labill.
Trunk6–20 ft., slender, black. Stipes blackish-brown, tubercled. Sori 6–12 on each segment 1. D. squarrosa. Trunk 6–20 ft., verystout, brown. Stipesshort, pale-brown, smooth. Sori 3–6 to each segment 2. D. fibrosa. Trunk wanting or very short. Stipes long, smooth, pale. Sori 6–12 to each segment 3. D. lanata.
| 1. | D. squarrosa,Swartz, Syn. Fil. 136, 355.—Trunk 6–20 ft., high, slender, black or dark-brown, clothed above with the per sistent bases of the old stipites. Fronds 4–8 ft. long, rarely more, 2–3½ ft. broad, oblong-lanceolate, 2–3-pinnate, rigid and coriaceous. Stipes slender, dark-brown or black at the base, paler above, when young clothed with long brownish-black hairs or setæ, almost gla brous when old, sides and under-surface rough with numerous small tubercles; rhachis and costæ clothed with deciduous reddish-brown wool above, rough with minute tubercles beneath. Primary pinnæ 10–20 in. long, 3–5 in. broad, oblong-lanceolate, acuminate; second ary 1½—3 in. long, ¼—½ in. broad, deeply pinnatifid. Barren seg ments ovate or oblong, rigid, sharply toothed, the teeth almost pungent fertile smaller and much contracted, pinnatifid. Sori copious, covering the whole under-surface of the frond, 5–12 on each segment or 1 to each lobule. Indusium rather large, both valves concave.—A. Cunn. Precur. n. 216; Raoul, Choix, 38; Hook. Sp. Fil. i. 68 Hook. f. Fl. Nov. Zel. ii. 9 Handb. N.Z. Fl. 351; Hook. and Bak. Syn. Fil. 51; Thoms. N.Z. Ferns, 31; Field, N.Z. Ferns, 50, t. 10, f. 6, and t. 25, f. 6. D. gracilis, Col. in Trans. N.Z. Inst. xv. (1883) 306.Trichomanes squarrosum, Forst. Prodr. n. 476.
North and South Islands, Stewart Island, Chatham Islands.—Abundant in woods throughout. Sea-level to 2500 ft.Weki or Wheki. Easily recognised by the slender blackish trunk, harsh and coriaceous fronds, dark-coloured stipes rough with small tubercles beneath, and rather large copious sori. The trunk is occasionally branched and sometimes produces numerous adventitious buds along its whole length, crowned with miniature fronds. A form possessing this peculiarity, and with the fronds rather narrower and more finely cut than usual, was described by Mr. Colenso as a distinct species under the name of D. gracilis.I cannot separate it even as a variety. |
| 2. | D. fibrosa,Col. in Tasmanian Journ. Nat. Sci.(1845) 19.— Trunk 8–20 ft. high, stout, columnar, everywhere thickly coated with matted fibrous aerial rootlets, giving it a diameter when mature of from 1–2 ft., clothed towards the top with the old pendent withered fronds. Fronds numerous, 30 or more, spreading, 4–8 ft. long, 1½—2 ft. broad, lanceolate, 2–3-pinnate, coriaceous but not so much so as in D. squarrosa.Stipes very short, clothed at the base with dense bright red-brown fibrillose scales; rhachisand costæpale-page 954brown, smooth, densely pilose on both surfaces with soft brownish hairs. Primary pinnæ 4–10 in. long, 1½–2½ in. broad, lanceolate, acuminate or almost caudate; secondary ¾—1½ in. long, ¼—½ in. broad, linear or linear-oblong, pinnatifid or pinnate at the very base. Segments rather close, falcate, acute the barren ones larger and broader, almost flat, acutely coarsely toothed; fertile smaller, contracted, concave, obtusely pinnatifid. Sori very numerous, covering the whole under-surface of the frond, small, 3–6 to each segment or 1 to each lobule.—Hook. Sp. Fil. i. 68, t. 23B Hook, and Bak. Syn. Fil. 461 Field, N.Z. Ferns, 51, t. 10, f. 5, and t. 25, f. 1. D. antarctica, Hook. f. Fl. Nov. Zel. ii. 10; Handb. N.Z. Fl. 351; Thoms. N.Z. Ferns, 31 (not of Labill.).D. intermedia, Col. ex Hook, and Bak. Syn. Fil. 461. D. Sparrmanniana, Col. in Trans. N.Z. Inst. xii. (1880) 364. D. microcarpa, Col. in Trans. N.Z. Inst. xx. (1888) 214.
North and South Islands From Tauranga and the Middle Waikato southwards, abundant in forests. Chatham Islands Miss Seddon!Sea-level to 2500 ft. Weki-ponga; Kuripaka. Very close indeed to the Australian D. antarctica, but a much smaller plant, with densely pilose rhachides and costæ, and smaller sori. Mr. Colenso's D. Sparrmanniana is a short-trunked form with rather broader fertile segments; and his D. microcarpa, has smaller and more finely cut fronds, with smaller sori; but they both merge gradually into the ordinary form. The Maoris formerly sliced the fibrous outside of the trunk into slabs, and used them in the construction of their food-houses, for the purpose of excluding rats. |
| 3. | D. lanata,Col. in Tasmanian Journ. Nat. Sci.(1845) 21.— Caudex usually long, prostrate and rooting, as thick as the wrist; more rarely short, stout, erect, and attaining a height of 3–6 ft. Fronds few, 3–6 ft. long, 1–3 ft. broad, ovate or ovate-lanceolate, acuminate, 2–3-pinnate, thick and coriaceous but hardly rigid, yellowish-green above, paler beneath. Stipes from half as long to as long as the frond, pale, smooth, clothed at the base with long purplish-brown or yellowish-brown fibrillose scales, when young more or less covered (together with the rhachis and costæ) with soft woolly deciduous hairs, almost glabrous when mature. Primary pinnæ 6–12 in. long, 2–4 in. broad, oblong-lanceolate, acuminate; secondary 1–3 in. long, ⅓–⅔ in. broad, pinnate or pinnatifid. Segments or pinnules rather closely set, slightly falcate barren oblong or ovate, obtusely or acutely toothed or lobulate fertile smaller and narrower, deeply pinnatifid. Sori copious, 6–12 to a segment or 1 to each lobule.— Hook. Sp. Fil. i. 69, t. 23c; Hook. f. Fl. Nov. Zel. ii. 10; Handb. N.Z. Fl. 351: Hook, and Bak. Syn. Fil. 461; Thoms. N.Z. Ferns, 31; Field, N.Z. Ferns, 53, t. 11, f. 1A, 1B, 1C. D. lævis, Heward ex Hook. Sp. Fil. i. 69.
North Island Hilly forests from Mongonui to Cook Strait, not common. South Island: Nelson—Massacre Bay, Travers;Pakawau, Kingsley!Westland—Okarito, A. Hamilton!Canterbury—Banks Peninsula, Armstrong.Sea-level to 2000 ft. page 955At Whangarei, Bay of Islands, and other northern localities this usually produces a short stout trunk, but to the south of Auckland it is invariably stemless. Possibly there may be two distinct varieties with a different geographical range, but so far I have failed to find distinctive characters to separate them. |