FLORA MALESIANA SERIES II - PTERIDOPHYTA Ferns and Fern Allies Volume 2, part 1 : Tectaria Group ^7^pr'}^ LmRARY THE NEW VORK BOTAKICAL GARDEN BRONX. NEW YORK X0458 FLORA MALESIANA SERES n — PTERIDOPHYTA Volume 2 Published for Foundation Flora Malesiana by Rijksherbarium/Hortus Botanicus • Leiden University • The Netherlands SZ'i FLORA MALESIANA SERIES II — PTERIDOPHYTA Volume 2 -part 1 -1991 Tectaria Group by R.E. Holttum t CIP-GEGEVENS KONINKLUKE BIBLIOTHEEK, DEN HAAG Flora Flora Malesiana / founded by C. G.G.J, van Steenis (1901-1986). - Leiden : Rijksherbarium / Hortus Botanicus Series II: Pteridophyta : Ferns and fern allies Vol. 2, pt. 1: Tectaria group / by R.E. Holttum. - 111. Comp. and publ. under the auspices of Foundation Rora Malesiana Met index. ISBN 90-71236-11-0 Trefw.: varens. All rights reserved © 1991 Foundation Flora Malesiana No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permis- sion from the copyright owner. Hora Malesiana ser. II, Vol. 2^ (1991) 1-132 TECTARIA GROUP (R.E. Holttum t, Kew)* Polypodiaceae subfam. Dryopteridoideae section A, auct.: C. Chr. in Verdoom, Man. Pteridol. (1938) 543, p.p. Aspidiaceae tribe Aspidieae auct.: Ching, Sunyatsenia 5 (1940) 250, excl. Lomariopsis and related genera. — Aspidiaceae, group of Ctenitis Copel., Gen. Fil. (1947) 153. Aspidiaceae auct.: Pichi Sermolli, Webbia 31 (1977) 460-468, p.p. Dennstaedtiaceae subfam. Tectarioideae Holttum, J. Linn. Soc. Bot. 53 (1947) 152; Revis. R. Malaya 2 (1955) 494; Studies fern genera I, Fern Gaz. 12 (1984) 313-319; Ibid. VI, Gard. Bull. Sing. 39 (1986) 153 -167. Caudex in almost all cases erect or suberect, always with a radially organized dictyo- stele; scales narrow and rather firm, marginal teeth (if present, except in Cyclopeltis) al- most always formed at the junction of two cells; i.e., the wall separating the two adjacent cells is elongated at right angles to the margin. Vascular structure of stipe consisting of small subequal vascular strands arranged in a U-formation as seen in transverse section (except in Pleocnemia where the arrangement is more complex), the two on the adaxial side variously enlarged. Fronds amply divided with free veins, or with broader divisions in which veins anastomose variously, in a few species simple, in most (except Heterogoni- um) the basal pinnae or lobes longest with elongate basal basiscopic lobes or pinnules; costae or costules of ultimate lamina-elements ± prominent on the upper surface, branch- ing directly from the prominent upper surface of the rachis bearing them, the margins of the lamina decurrent on the sides of the rachis. Hairs consisting of several cells, not inter- grading with scales, variously present on most parts of the frond, the prominent upper surface of costae of lamina-segments in a majority of cases (at least near the base) covered with short erect hairs of several cells, the outer cell-walls thin and collapsing on drying (in other cases hairs in this position may remain firm on drying); unicellular glands usually ± cylindric, colourless or red to yellow, variously present on surfaces of leaflets, on indusia, and on stalks of sporangia in some genera. Sori usually orbicular, covered with reniform or peltate indusia, or exindusiate, in the latter case sometimes spreading along veins. Fertile pinnae or leaflets in some species much contracted, with sporangia borne all along the veins to produce an acrostichoid appearance. Spores in most cases with a peri- spore folded into wings or crests, the wings variously anastomosing, the perispore in other cases spinulose or with obtuse projections. Base chromosome number 40 or 41. Distribution — Pantropic with greatest diversity in the Old World; about 20 genera. Taxonomy — In the 19th century the form of sori and condition of venation (free or anastomosing) were by most authors regarded as the most important bases for classifica- tion. Thus the free-veined members of the present group were associated with Dryopteris and free-veined Thelypteridaceae , and exindusiate species were separated generically. This led to confusions of various kinds. *) Dr. Holttum submitted the manuscript of his revision of the Tectaria Group for publication in Flora Malesiana not long before he passed away in September 1990. Some distributional data were added by the Editor. The illustrations are by P. J. Edwards, Kew. Hora Malesiana sen II, Vol. 2^ (1991) The first major work in the 20th century was Christensen's subdivision of the unnatu- ral aggregate of species under Dryopteris in his Index Filicum (1905) which included all free-veined ferns with reniform indusiate sori and their obvious exindusiate relatives. For the first time he distinguished Ctenids from Dryopteris, pointing out the relationship of the former to Tectaria and also the distinctive characters of thelypteroid ferns (some of which have anastomosing veins). In his last major survey of the classification of all ferns (1938) he retained a major family Polypodiaceae with Dryopteridoideae as one subfamily; this included, in section A, Dryopteris and Tectaria with other genera related to them, with Thelypteridaceae in section B. In 1940 Ching divided Christensen's Polypodiaceae into several families, one being Aspidiaceae, similar to Christensen's Dryopteridoideae section A of 1938. Ching divided it into two tribes, Aspidieae and Dryopterideae. In 1947 Holttum accepted Ching's two tribes, with minor changes, but placed them as subfamilies in a major family Dennstaed- tiaceae, with the idea that Polypodium and its immediate allies form a very different group of ferns. Copeland, writing independentiy in 1947, recognized a large family Aspidiaceae, including Thelypteris and its allies, also AthyriumI Diplazium and the Lomariopsis group of genera. In his conspectus (1947: 153) the genera here dealt with appear as allies of Ctenitis; to them should be added Cyclopeltis which he associated with Polystichum, and DryopolyStichum excluded. Pichi Sermolli (1977) included both dryopteroid and tectar- ioid genera in his family Aspidiaceae and did not accept a division of it into two groups. Holttum (1984) discussed the above history in more detail, still retaining separate groups associated with Dryopteris and Tectaria and objecting to the Tryons' arrangement in their book of 1982 in which the two groups are confused. In 1986 Holttum presented a conspectus of all Old World genera of the Tectaria alliance, with comments on those of the New World, pointing out the peculiar characters of Dryopsis Holttum & Edwards [Kew Bull. 41 (1986) 171-204] which perhaps connects the two groups. Most species of Dry- opsis are in Mainland Asia but two are Malesian. The structure of the junction of the bases of leaflets and the rachis that bears them is here presented as the most clear distinction between the genera allied to Dryopteris and those allied to Tectaria. This is seen best in Lastreopsis, Ctenitis and Pteridrys (see fig. 311 in Holttum 1955: 524). In Lastreopsis the relationship is exactly as in Davallia; Ctenitis only differs in the margins of the lamina which are not thickened where they are decurrent on the rachis-wing. In Cyclopeltis the relationship of pinna-base to rachis is only evident near the apex of the frond. An arrangement close to Davallia is also shown by Rumohra, a genus included by several authors in Aspidiaceae. But Rumohra differs from all the genera here included in its strongly dorsiventral rhizome- structure, compar- able to that of Davallia though not identical with it, and also in its scales. [Pichi Sermolli (1977: 465) cites Chandra's study of the vascular structure in the caudex of Maxonia as evidence of dorsiventrality in a ally of Dryopteris; but the dorsiventrality in Maxonia is only a slight modification of the normal dictyostele of Dryopteris, very different from that in Rumohra.] Rumohra differs from Davallia in its distribution (widely in South America, also in southern Africa and Australasia) and in its spores. In Malesia, it only occurs in New Guinea. It is perhaps a connecting link between Davallia and the Tectaria group; it needs a comprehensive new morphological study. Holttum — Tectaria Group Pichi Sermolli (I.e. 1977: 238) has stated that there are four different types of rachis- structure in Aspidiaceae but he deals only with the junctions of main rachis with pinna- rachises, not with the relationship between lamina-elements and the smaller distal rachises which I believe to be significant. I have expressed disagreement with him in 1984 (I.e.: 314). KEY TO THE GENERA 1 a. Teeth present at the bases of sinuses between pinna- or pinnule-lobes, the teeth pro- jecting out of the plane of the lamina 2 b. Teeth of this kind lacking 3 2a. Fronds simply pinnate with free veins; no unicellular glands on lamina or in sori Pteridrys (p. 4) b. Fronds mostly bipinnate, their veins forming at least costal areoles; cylindric glands present Pleocnemia (p. 8) 3a. All axes of the frond bearing copious scales, the smaller ones at least partly clathrate with isodiametric cells Ctenitis (p. 21) b. Smaller axes of the frond bearing few scales which are not thus clathrate 4 4a. Veins in sterile fronds anastomosing copiously; free veinlets in areoles (including those along costae) variously directed and in most species forked 5 b. Veins anastomosing to form costal areoles which lack free veinlets, or all veins free 7 5a. Fertile fronds greatly contracted and bearing indusia 6 b. Fertile fronds not greatly contracted, or if so lacking indusia Tectaria sect. Tectaria (p. 59) 6a. Sterile fronds simple; fertile ones irregularly deeply lobed; indusia reniform Tectaridium (p. 36) b. Sterile fronds pinnate; pinnae of fertile fronds linear, with continuous indusia along each side of the costae Chlamydogramme (p. 37) 7a.