OBSERVATIONS ON THE GENERA PHEGOPTEPdS, PSEUDOPHEGOPTERIS AND MACROTHEL YPTERIS BY PRAKASH CHANDRA (National Botanic Gardens, Lucknow) Received June 2, 1972 (Communicated by Dr. T. N. Kho shoo, r.A.s¢. ) ABSTRACT Morphology of seven species of exindusiate thelypteroid ferns belong- ing to three genera, viz., Phegopteris, Pseudophegopteris and Macrothelyp- teris is described. The paleae are gland-tipped except in M. ornata, P. hexagonoptera and P. decursive-pinnata where it is non-glandular. The dictyostele consists of 2-4 vascular strands. The lamina bears reduced scales (sometimes branched) mixed with the hairs, both acievlar and glandular. The sori are usually exindusiate; in P. decursive-pinnata the indusium is modified into tufts of fascJculated hairs whereas in M. torre- siana a small fugaceous indusium is present. The trichomes are borne on the capsule wall only. Spores are of bilateral type aad usually peri- hate. The exine is smooth or verrucate; in P. aurita and P. pyrrhorhachis it bears narrow ridge-like irregular reticulations. In M. ornata, the exine as well as perine are spinulose. It is concluded that the exindusiate species are quite distinct from the other members of the family and constitutes a natural group. INTRODUCTION THE exindusiate thelypteroid ferns have been variously circumscribed under the genera Phegopteris, Pseudophegopteris and Macrothelypteris (Ching, 1936, 1963; Iwatsuki, 1965; Holttum, 1969). Of the three known species of the genus Phegopteris, the two (P. hexagonoptera, P. connectilis) are distri- buted throughout the North temperate zone and one (P. decursive-pinnata) in S.E. Asia. Ching (1963) assigned 10 species each to the genera Pseudo- phegopteris and Macrothelypteris. However, Holttum (1969)ascribed 20 species under the genus Pseudophegopteris. From India, 8 exindusiate species were recorded by Beddome (1892). There is much confusion with regard to the phylogeny and relationship of the exindusiate species of thelypteroid ferns. But for the little informa- 68 Genera Phegopteris, Pseudophegopteris and Macrothelypteris 69 tion available (Chandra, 1963 ; Nayar and Chandra, 1965) not much is known about this group. The present study was undertaken for the better under- standing of this group of ferns and deals with 7 species, viz., Phegopteris connectilis (Michx.) Watt, P. decursive-pinnata (Van Mall) Fee, P. hexa- gonoptera (Michx.) Fee, Pseudophegopteris aurita (Hook.) Citing, P. pyrrhorha. chis (Kze.) C/ling, Macrothelypteris ornata (Wall ex Bedd.) Ching and M. torresiana (Gaud.) Ching. All the species are mesophytic terrestrial ferns growing mostly in exposed or partially shaded forest beds. M. ornata and M. torresiana are generally restricted to semi-marshy areas near the streams and waterways and occur usually as isolated plants. The plants of P. aurita and P. pyrrhorhachis, however, form shaggy Loose_colonies with the individual plants rather sparse and often mixed with dense vegetation. MATERIAL AND METHODS The plants were collected mainly from Khashi and Jaintea Hills and N. Cachar Hills of Assam. In the case of M. torresiana, the fresh material was used from the plants growing in the fernery of N.B.G. The herbarium speci- mens of P. connectilis and P. decursive-pinnata were procured from Makino Herbarium, Japan and from the herbarium of Fred G. Floyds, England. The spore morphology was studied from acetolysed preparations as well as from fresh spores mounted in glycerine jelly. OBSERVATIONS The rhizome is generally wide creeping except in M. ornata and M. torre- siana where it is short, stout and ca. 2-3.5 cm across; it is usually suberect in P. decursive-pinnata. The paleae mixed with the unicellular acicular hairs cloth the leaf bases and the surface of the rhizome. They are basally attached, non-clatherate, ovate-lanceolate and usually gland-tipped as in P. aurita (:Figs. 1, 11), P. pyrrhorhachis (Fig. 3), P. connectilis (Fig. 2) and M. torresiana (Fig. 9). In M. ornata (Figs. 5, 15), P. hexagonoptera (Fig. 4) and P. decursive, pinnata (Fig. 6) the apex of palea is non-glandular and terminated by an elon- gated thick-walled, acicular hair. The paleae are profusely hairy; the elon- gated acicular hairs are borne all over the margin (sometimes on the surface as in P. connectilis) of the paleae. In addition, unicellular, capped papillate hairs with hyaline protoplasmic contents occur on the margin of the palea. In P. aurita a few large, subglobose, unicellular hairs mixed with the papil- late ones are borne on the margin of the young palea ; in some cases some of Acad. B2 70 PRAKASH CHANDRA these hairs may be stalked. These hairs are different from the papillate ones in being larger, swollen, with yellowish contents and devoid of any secretion. The palea originates as a uniseriate hair-like appendage composed of short discoid cells (Fig. 7). Early in the development, the terminal cell becomes much inflated, balloon-like and acquire dense nearly hyaline cytoplasmic contents (Figs. 8-11). However, in M. ornata, the terminal cell instead of swolling into a glandular structure, elongates excessively becoming acicular hair with slightly swollen base (Figs. 12-15). The marginal papillate and glandular hairs are developed early when the body of the palea is 4-8 cells broad (Figs. 9-11, 15). The ground tissue of the rhizome is parenchymatous with dense deposits of starch (Figs. 17, 19, c). The sclerenchyma strands are entirely absent in the ground tissue of the rhizome. The vascular cylinder is a dictyostele, dissected usually into 2 broad ribbon-shaped meristeles (Fig. 18) by spirally arranged leaf gaps ; in P. com~ectilis and P. sexagonoptera, the meristeles are sometimes 3-4 in a transverse section. Xylem tissue usually consists of 1-4 rows of large metaxylem tracheids (Figs. 17, 19, rex) and small scattered groups of protoxylem on its outer surface. The phloem is scanty compared to the massive xylem on all the sides (Figs. 17, 19, ph). Pericycle is usually 2-3 layered (Fig. 19, p). Endodermis is well differentiated and consists of a single layer of radially compressed cells with their radial walls slightly thickened (Figs. 17, 19, n). The leaf gaps are short in most of the species except in the case of long creeping rhizome (P. aurita) in which it is much elongated. Branch- ing of the rhizome is fairly common in the species having creeping rhizome and is of the sub-dichotomous type with the stelar cylinder splitting nearly equally into two (Fig. 22, bg). The leaves are usually simply pinnate except in M. ornata and M. torresiana where it is characteristically decompound. The stipe is glabrous, usually devoid of scales ; in hi. ornata the stalks of the paleae persist as warts making the surface of the stipe sub-muricate. In some species like M. torresiana the surface of the mature stipe has a prominent waxy covering; the stipe when young, however, bears unicellular glandular hairs all over the surface. The ~ascular supply of the slipe consists of a pair of broad, ribbon-shaped, ltea- rally placed vascular strands (Fig. 21). The xylem cells are usually 1-3 ceils thick and in some species the cells are highly corrugated (M. ornata, Fig. 20). The phloem surrounds the xylem on all the sides and in M. ornata groups of large secretory cells occur in the phloem tissue on the inner surface of the Genera Phegopteris, Pseudophegoptefis and Maerothelypteris 71 Y I r J ."50P 4 72 6 I \ 7 9 14 15 -,,o, - 20 ~ Smm ~' Ph ~ ~mx bZ ' l g 22 Fzos. 1-22. F~s. 1-2. Palea of P. attrita (Fig. 1) and P. eonnectilis (Fig. 2). Figs. 3-5. Apical region of the mature palea of P. pyrrhorhachis (Fig. 3), P. hexagonoptera (Fig. 4) and M. ornata (Fig. 5). Fig. 6. Palea of P. decursive-pinnata. Figs. 7-10. Stages in the development of palea of P. pyrrhorhachis (Fig 7), M. torresiana (Figs. 8, 9), P. aurita (Fig. 10). Fig. 11. Young palea of P. aurita. Figs. 12-15. Stages in the development of palea in M. ornata. F!g. 16. Marginal hairs on the young palea of P. ato'ita. Fig. 17. T.S. Rhizome of P. connectilis. Fig. 18. T.S. Rhizome of P. attrita. Fig. 19. A portion of the same showing cellular structure. Fig. 20. T.S. of the rachis of M. ornata. Fig. 21. T.S. of the stipe of M. ornata. Fig. 22. Vascular cylinder cf a portion of rhizome of P. aurita. (b, branch traces ; c, cortical cells ; e, epidermis; n, cndodermis; p, pericycle; bg, branch gap; lg, leaf gap; It, leaf trace; ph, phloem; rex, metaxylem.) 72 PRAKASH CHANDRA vascular strand opposite the protoxylem. These cells in the mature stipe may disintegrate forming lysigenous cavities filled with mucilage. The rachis is similar to the stipe in structure; it is muricate in M. ornata. In P. hexagonoptera, P. decursiPpinnata and P. connectilis elongated uni- cellular acicular hairs are profusely borne on the surface of the rachis; in other species the rachis is glabrous. The vascular bundle of the rachis is solitary, gutter-shaped and often with the base more or less flattened and the sides divergent (Fig. 20). The vascular supply of the secondary rachises and of the pinnae originate as intramarginal branches from the vascular strand of the main rachis. The pinnae are sessile and subopposite to alternate usually connected by a wing along the rachis. There is a prominent brown coloured elongated gland at the base of pinnae near the point of attachment to the rachis in P. aurita. The leaf lamina is usually herbaceous and thin in texture. Both the upper and lower epidermis are chlorophyllous. The cells of upper epio dermis are large and irregularly disposed. The anticlinal walls are broadly sinuous (Fig. 24). The lower epidermal cells are irregular and disposed more or less parallel to the veins.