J. Hauori Bot. Lab. No. 79: 129- 138 (Feb. 1996)

SPORODERM AND ELATERODERM DIVERSITY IN SOME RARE AND INTERESTING INDIAN LIVERWORTS UNDER SEM2

VIRENDRA NATH1 AND A. K. ASTHANA1

ABSTRACT. Sporoderm and elateroderm pattern under SEM have been investigated in seven rare and interesting Indian liverworts: Calobryum indicum Udar et Chandra, C. dentatum Kumar et Udar (Calobryales), Schiffneria hya/ina Steph., Trichocolea tenera Udar et Singh (Jungermanniales), cristula Aust., F. pusi/la (L.) Dum. and Petalophyllum in ­ dicum Kash. (). The diagnostic features of each taxon have also been provided.

INTRODUCTION Spores in liverworts exhibit an interesting range of diversity in their sporoderm ornamentation. Distinctiveness of sporoderm sculpturing is unambiguous in hepaticae and can therefore be convincingly applied for systematic treatment of various taxa. Elaters also exhibit distinct structural patterns and ornamentations. Studies on sporoderm morphology of Indian Hepaticae and Anthocerotae under LM (Light Microscope) has already received considerable attention by Mehra and Sood ( 1969), Srivastava and Udar ( 1975), Udar ( 1976) and Gupta, and Udar ( 1986). SEM (Scanning Electron Microscope) studies have resolved some micromorphological det­ ails of sporoderm which could not be discerned using LM (Light Microscope). Utilizing the efficiency of SEM, studies on hepatic spores have been made by several workers at global level (Taylor et al. 1974; Clarke, 1979; Jovet-Ast, 1979; Geissler and Gradstein, 1982; Stienkamp and Doyle, 1984; Inoue and Hibino, 1984; Scott and Pike, 1984, 1987, 1987a, 1987b, 1988, Bischler, 1989, Brown and Lemmon, 1993; Jovet-Ast, 1993). Such studies have received attention in Indian Hepaticae by Udar and Shaheen (1983), Udar and Kumar (1983), Udar and Srivastava (1983), Udar and Srivastava, G . (1983), Udar et al. (1983), Udar and Awasthi (1983), Udar and Jain (1983), Udar and Srivastava (1984), Udar and Agarwal (1985), Srivastava (1986), Sinha et al. (1987), Asthana and Srivastava (1991), Nath and Asthana (1992), Sharma and Srivastava (1993). The present study provides SEM details of sporoderm and elateroderm of Calob­ ryum indicum, C. dentatum, Schiffneria hyalina, Trichocolea tenera, Fossombronia cristula, F. pusilla and Petalophyllum indicum. The study has shown intergeneric as well as interspecific variability in surface ornamentations both in spores and elaters, which are considered the best taxonomic tool for discrimination of genera and species.

1 Bryology Laboratory, National Botanical Research Institute, Lucknow-226 001. India. 2 NBRI Research Publication No. 436 (N.S.) . 130 J. Hattori Bot. Lab. No. 79 I 9 9 6

MATE RIALS AND METHODS Fertile specimens were collected from different bryologically rich localities of the Western Himalayas, Eastern Himalayas and South India. Thoroughly cleaned mature capsules were subjected to dehydration through the usual ethanol series followed by critical point drying. The dehydrated capsules were incised and non­ acetolysed spores and elaters were examined under SEM (JEOL-JSM 35c). The Voucher specimens were deposited in the Herbarium, National Botanical Research Institute, Lucknow (LWG).

DESCRIPTIONS l. Calobryum indicum Udar et Chandra, Revue Bryol. et Lichenol. 33(3-4): 555-559 (1964-65). Pl. 1, figs. 1, 2. strictly acrogynous, dioecious, 6- 12 mm long, gametophores erect arising from upturned tips of an interwoven tangled mass of rhizome; leaves mostly crowded at apex of axis, broader than long with entire margin; antheridia borne at apex in group forming a dome-like structure. Spores: More or less spherical, minutely papillate yellowish-brown, 2(}-25 µm in diameter, sporoderm exhibited dense round headed papillae over the entire surface, exine occasionally folded. Elaters: Yellowish-brown, bispirally thickened tapering ends, 35(}-700µm long, elateroderm exhibiting the presence of minute tubercles scattered over the surface. Specimen examined: India. Eastern Himalayas: West Bengal, Darjeeling, (Gauri­ bas 27 °N, 88.25 °E; alt. ea. 3000m), 23.5.1981, leg. S. Chandra and V. Nath, LWG 203814-B. Growing on soil.

2. Calobryum dentatum Kumar et Udar, J. Indian bot. Soc. 55: 23- 30 (1976). Pl. 1, figs . 3, 4. Plants strictly acrogynous, dioecious 8- 12 mm (- 15 mm) long, axis leafy through­ out; leaves usually longer than broad; upper two cycles including the female bracts prominently dentate; oil-bodies 5(}-70 in leaf cells; antheridia borne in the axils of two upper cycles of leaves or terminal. Spores: Yellowish brown, 18- 24 µm (- 27.5 µm) in size, sporoderm conspicuously folded and studded with minute tubercles. Elaters: Light brown, bispirally thickened, with tapering ends remarkably shorter than C. indicum up to 440 µm long, elateroderm appearing more or less smooth as compared to C. indicum except two or three (or even more) minute tubercles. Specimen examined: India. Eastern Himalayas: West Bengal, narjeeling (Gauri­ bas, 27 °N, 88.25 °N; alt. ea 3000m), 23.5.1981, leg. S. Chandra and V. Nath, LWG 203814-A. Growing on soil.

3. Schiffneria hyalina Steph. Oest. bot. Zeitschr, 44: 1 (1894). Pl. 1, figs. 5, 6. Plants dorsiventrally flattened, thalloid, 17 mm X 3 mm, laterally lobed; sex organs V. NATH & A. K. AsTHANA: Sporoderm and elateroderm diversity 131

Plate 1. Figs. I, 2: Calobryum indicum Udar et Chandra. I. Spore ( X4000); 2. Elater ( X 3000). Figs. 3, 4: Calobryum dentatum Kumar et Udar. 3. Spores in cluster ( X 2400); 4. Elater ( X 2400). Figs. 5, 6: Schijfneria hyalina Steph. 5. Spore ( X 4800); 6. Elaters with few spores ( X 540). 132 J. Hattori Bot. Lab. No. 79 I 9 9 6 borne on leafy shoots arising from ventral surface or apex: antheridium occurring singly in the axil of saccate bracts, female shoots bearing terminal perianth, oblong, smooth-walled with dented mouth; capsule wall bistratose having nodulose-slightly elongated thickenings on each alternate longitudinal wall of epidermal layer. Spores: Light yellowish brown, 12.5- 15 µm in diameter. Under SEM sporoderm exhibiting densely verrucose to pseudoreticulate pattern, proximal face marked with a thick triradiate mark. Elaters: Yellowish brown, 140-280µm long, bispirally thickened with rounded ends, under SEM elateroderm appearing more or less smooth. Specimen examined: India. Eastern Himalayas: West Bengal, Darjeeling (Sanda­ kphu-Tanglu 27.05°N, 88 °E, alt. ea 3000m), 26.4.1965, leg. S. Chandra, LWG 202450 Bry. Growing on decayed logs in association with Plagiochila sp. and mosses.

4. Trichocolea tenera Udar et Singh, Geophytology 7: 69 (1977). Pl. 2, figs. 1- 4. Plants in tufts, usually 60-90 mm long, regularly bi pinnate, stem delicate, main stem 281 - 346 µm wide, 8-12 cells across diameter, cortex single layered; leaves in three rows, underleaves smaller, about half as wide as lateral leaves, lamina of underleaves on main stem bearing rhizoidal disc bearing tufts of rhizoids, androecial branches similar to vegetative branches bearing 1 or rarely 2 antheridia in the axil of each bract; female plant bearing terminal coelocaule, oblong, wider at mouth with paraphyllia. Spores: Yellowish-brown, 15-17.5 µm in diameter, sporoderm densely vermiculate with ridged exine. Sometimes these ridges form a reticulum enclosing irregularly shaped lumina. Proximal face bearing a prominent elevated triradiate mark. Elaters: Brown, 13 7. 5- 192. 5 µm long, bis pi rally thickened with prominent taper­ ing ends. Elateroderm more or less smooth in nature. Specimen examined: India. Eastern Himalayas: West Bengal, Darjeeling (Senchal lake, 27 °N, 88.25 °E, alt. ea 3000m), 18.5.1981, leg. S. Chandra and V. Nath, LWG 203723. Growing on moist humus on road side.

5. Petalophyllum indicum Kash., J. Indian bot. Soc. 7: 14 (1928). Pl. 2, figs . 5, 6. Plants dioecious, simple or furcate, 12 mm X 7 mm, basal portion cylindrical and wingless with fanning apex having parallel, erect leaf appendages forming lamellae on the dorsal surface; wings or lamellae multi-layered at base gradually becoming single layered above, wavy along the margin; antheridia in groups behind the apex, protected by scattered scales; sporogonia 1- 4, usually one in each perianth; capsule wall usually 3-layered; inner layers with thick annular or sometimes semiannular bands. Spores: Dark brown, spherical, 40 µm in diameter, sporoderm exhibiting membra­ nous elevated lamellae forming a perfect reticulate pattern, reticulations penta­ hexagonal in shape, 8- 10 µm, usually 3- 4 reticulations across the diameter, marginal wings possessing fine striations. Elaters: Bi-trispiral, lightly coloured, spirals very distinct, brown, 280-400 µm long, 8- 10 µm broad, sometimes branched, elateroderm exhibiting prominent striations except on spiral band (Pl. 2, fig . 6). V . NATH & A . K. ASTHANA: Sporoderm and elateroderm diversity 133

Plate 2. Figs. 1-4: Trichocolea tenera Udar et Singh. 1. Group of spores ( x 3600); 2. Bunch of elaters and spores ( X 720); 3. Spore ( X 4800); 4. Elater with few spores ( X 1000). Figs. 5, 6: Petalophyllum indicum Kash. 5. Spore ( X 2000); 6. Elater (a portion X4000).

Specimen examined: India. Western Himalaya: Uttar Pradesh, Chamoli (30.4°N, 79.5 °E; alt. ea. 2500m), March 1978, leg. S.S. Bir, LWG Bir/78. Growing on soil.

6. Fossombronia cristula Aust., Acad. Philad. p. 288 (1866). Pl. 3, figs. 1- 3. Plants monoecious, leaves flat, somewhat wavy at the margin, each lobe with mucilage papilla at apex, unistratose except at base. Spores: Yellowish brown to dark brown, 43- 58 µm in diameter, sporoderm exhibiting a perfectly reticulate pattern formed by coalition of elevated lamellae on 134 J. Hattori Bot. Lab. No. 79 I 9 9 6 distal face, usually 5- 7 luminae (meshes) across the diameter, perispore well developed at periphery, with crenulate margin. Proximal face entirely devoid of lamellae and possessing minute papillae. Elaters: Inadequately developed pale yellow, 24- 115 µm long having annular­ bispiral thickenings, elateroderm appearing more or less smooth, without any ornamen­ tation. Specimen examined: India. South India: Kerala, Wayanad (Periyar, 10. l 0 N, 76.4°E; alt. ea. 600m), 9.8.1984, leg. S. Chandra and V. Nath, LWG 204069. Growing on soil.

7. Fossombroniapusilla (L.) Dum., Ree. d'obs. p. 11 (1835). Pl. 3, figs. 4- 6. Plants dioecious; stem without tubers; leaves usually broader than long, irregularly lobed, unistratose throughout except at base where more than one cell thick. Spores: Dark brown, 47- 55 µm in diameter, under SEM distal face of sporoderm lamellate, exhibiting characteristic high lamellae usually continuous and forked at periphery; spines and perispore well developed, spines up to 19 at the periphery, proximal face without distinct lamellae, however, it has some minute papillae and poorly developed triradiate mark. Elaters: Well developed, 90-288 µm long, trispiral (rarely 2 or 4 spiral) spirals brown, under SEM elateroderm exhibiting presence of small and big granules over spiral bands all along its length. Specimen examined: India. South India: Kerala, Dist. Wayanad (Thirunelly 1 l.5°N, 76.2°E alt. ea. 900 m), 8.8.1984, leg. S. Chandra and V. Nath, LWG 204051. Growing on soil.

DISCUSSION An investigation of sporoderm and elateroderm pattern under SEM has revealed the existence of a remarkable range of diversity in the micromorphological character­ istics of the taxa belonging to three different orders of Hepaticae i.e. Calobryales, Jungermanniales and Metzgeriales. Spores of Calobryum indicum are clearly distinct from those of C. dentatum by the absence of prominent folds on exine, more or less spherical shape (Pl. 1, fig. 1), however, both of the above species possess round headed papillae on the exine. As far as the elateroderm is concerned, the former species exhibits scattered minute tubercles over spiral bands while in the latter it is more or less smooth. Schiffneria hyalina Steph. possesses densely verrucose sporoderm ornamentation, which coalesce to form a pseudoreticulate pattern (Pl. I, fig . 5); this is clearly distinctive from all other taxa, though the elateroderm is smooth. Trichocolea tenera exhibits a finely vermiculate - densely granulose sporoderm ornamentation, in addition to this, the exine showed conspicuous ridges, which some­ times joined in a reticulate manner. Thus the spores of above taxon are clearly distinctive in their architectural pattern. In Petalophyllum indicum the spores are typically reticulate comprising winged V. NATH & A. K . AsTHANA: Sporoderm and elateroderm diversity 135

Plate 3. Figs. 1-3: Fossombronia cristula Aust. 1. Spores (distal face X2000); 2. Spore (proximal face X 2000); 3. Elater ( X 1000). Figs. 4- 6: Fossombronia pusilla (L.) Oum. 4. Spore (distal face X 1500); 5. Spore (proximal face X 1500); 6. Elater (a portion X4000). 136 J. Hattori Bot. Lab. No. 79 I 9 9 6 ridges, wings are striated which is a unique feature characterizing this taxon. Meshes (areole) are usually pentagonal. Unlike elaters of other plants, it possesses a striated elateroderm, however, the spirals are smooth. The sporoderm pattern in Fossombronia cristula is distinctively different from that of F. pusilla as the former possesses a perfect reticulate pattern (Pl. 3, fig . 1), however, the latter has more or less parallel high lamellae (Pl. 3, fig . 4 ), which are usually bifurcated at the periphery. As far as the elaters are concerned, they are less developed in the former species while well developed and usually trispiral and loosely packed in the latter species. In addition to this some minute tubercles have also been observed on the spirals (Pl. 3, fig. 6). Earlier, Scott and Pike (1987, 1988) provided SEM details of spores in some species of the Fossombronia. A comparative study has revealed that F. longiseta (Aust.) Aust., F. dentata Steph., F. vermiculata Scott et Pike, F. microlamellata Scott et Pike, F. a/tilamellosa Scott et Pike, F. rupestris Scott et Pike, F. fernendiziensis Steph. F. crassifolia Spruce and F. taenifolia Spruce are comparable to F. pusil/a (L.) Dum. in possessing a lamellate sporoderm pattern and the latter two species have been reduced under F. pusilia, whereas F. fernendiziensis is treated as synonym of F. wondraczekii. As far as the rest of the above species are concerned, F. longiseta and F. dentata are distinctive from F. pusilla in possessing a greater number of spines (20 or more and 20-34 respectively) at the periphery and the larger size of the spore (48- 78µm), F. altilamellosa, F. rupestris and F. vermiculata also differ from F. pusilla in having larger spores ( 54- 83 µm, 54- 77 µm and 48- 78 µm respectively) as well as a greater number of spines (16--31, 20-30 and 20 or more respectively) at the periphery. Similarly, F. microlamellata can be easily distinguished from F. pusilla by short and squarish lamellae of the sporoderm, smaller spores (25- 34 µm) and the more or less smooth proximal face. The sporoderm pattern of Fossombronia brasiliensis Steph, F. foveo/ata Lindbg. described by Inoue and Hibino ( 1984) and the sporoderm pattern of F. tesseletta Scott et Pike provided by Scott and Pike ( 1987) closely resemble F. cristula Aust. in having perfect reticulations, however, the former two species are distinctly different from F. cristula in possessing a lower number of areolae or meshes (up to 4) across the diameter, and the latter species can be easily recognized by the smaller size of spores (30-41 µm) and greater number of areolae or meshes (7- 12) across the diameter. Scott and Pike (1987a) created foveolata complex to include 7 species of Fossom­ bronia having a reticulate sporoderm pattern. A close resemblance in F. foveolata and F. cristula has also been noticed, however, elater have clearly made the two species distinct. The SEM details of spores of Type specimen of F. cristula provided earlier by Scott and Pike (1987a) differ from spores of our Indian specimens in having smaller size (36- 42µm) and 3- 5 areolae (meshes) across the diameter of the spores. The present study has revealed that sporoderm is minutely papillate in Calobryum indicum and C. dentatum, verrucose-pseudoreticulate in Schiffneria hyalina, densely vermiculate-reticulate in Trichocolea tenera, distinctly reticulate in Petalophyllum in­ dicum and Fossombronia cristula, lamellate in F. pusilla whereas elateroderm is striated V. NATH & A . K . ASTHANA: Sporoderm and elateroderm diversity 137 and granulated in Petalophyllum indicum and Fossombronia pusilla respectively, min­ utely tuberculated in Calobryum indicum and smooth in the remaining four taxa.

ACKNOWLEDGEMENTS The authors gratefully acknowledge Dr. P.V. Sane, Director, National Botanical Research Institute, Lucknow for providing all necessary facilities and encouragement and the Council of Scientific and Industrial Research, New Delhi for providing financial assistance.

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