The African Fissidens enervis Sim is reported from the Western Ghats (India). This is the first Asian record.
The Western Ghats, a 1600 km long chain of hills along the western coast of Peninsular India with a major discontinuity, the Palghat Gap, is the most influential geomorphic feature in the region. The geological history of the Indian Peninsula as an original part of Gondwanaland, followed by tectonic movement northwards and collision with the Asian continent, have shaped its diverse of flora and fauna. Western Ghats is an abode of many unique elements such as the purple frog (Nasikabatrachus sahyadrensis) (Biju and Bossuyt 2003), which points to the African connection. Paleotropical Fissidens species are F. crispulus Brid. (Bruggeman-Nannenga 1997), F. planifrons Besch. (Blockeel et al. 2003) and F. punctulatus Sande Lac. (Bruggeman-Nannenga and Arts 2010). Fissidens crispulus and F. punctulatus are wide-spread species. The distribution of F. planifions and F. enervis is more restricted. The first is known from Tanzania, Madagascar, the Comoro Islands, La Reunion and Sri Lanka. Fissidens enervis is known only from South Africa and the Western Ghats. The present find from the Western Ghats is the first Asian record of the African F. enervis.
Fissidens enervis Sim, Trans. R. Soc. South Africa 15: 187, 1926. Type: Natal, Pietermaritzburg, Town Bush Valley, Sim 9899 (lectotype (designated by Magill 1981) PRE!)
Growing scattered; rhizoids basal, from lower stem cortex and some from the lamina, hyaline or brown, smooth; stem unbranched, with up to 13 µm wide cortical cells, 1.5–5.0 × 1.0–2.5 mm tall, pinnate; leaves pinnate, pale green, distant, 4–7 pairs, crispate when dry, elliptical with cuspidate tip, 0.30–1.30 × 0.12–0.25 mm, 3–5 times as long as wide, limbate; limbidium reaching the leaf apex, confluent or not, confluent at the apex of the vaginant laminae, reaching the insertion of the dorsal lamina, reaching the insertion of the vaginant lamina or not, in mid of dorsal lamina 11–16 µm wide, probably bistratose (no cross-sections seen), on vaginant laminae 11 µm wide, bistratose, marginal throughout; vaginant lamina ± 1/2 the leaf length, at the base narrower than the stem, slightly rounded at insertion, unistratose, subequal; dorsal lamina slightly rounded to ± straight towards the insertion, reaching the insertion, not decurrent, unistratose; costa lacking (vestigial in perichaetial leaves of type (surface view); mid dorsal laminal cells large, plane, 32–67 × 16–25 µm; mid vaginant laminal cells large, plane, 31.5–54.0 × 16.0–25.5 µm; gemmae not seen.
Perigonia terminal on small, ca 1.5 mm long plants; antheridia 230 µm long; perichaetia terminal, perichaetial leaves 1.1–1.3 mm long with proximally widened vaginant laminae; archegonia 140–160 µm long; Sporophyte: setae ± 4 mm long, smooth; capsule symmetrical, 0.50 × 0.25 mm, ± 32 columns of quadratic-oblong exothecial cells. Peristome scariosus-type, teeth ± 33.5 ×m wide at base. Spores not seen.
Diagnosis and comparison
Fissidens enervis is characterized by its cuspidate leaf apices, ecostate leaves and large laminal cells. Moreover, it frequently has rhizoids growing from the lamina. In India it may be confused with the also ecostate, limbate species F. hyalinus Wilson & Hook. (= F. nymannii Fleisch.) that is known from Mexico, USA, New Zealand, Australia, New Caledonia, Fiji, New Hebrides (Vanatu), the Philippines, Indonesia, India, China, Taiwan, Japan and Russia (Tan and Iwatsuki 1991, Iwatsuki and Suzuki 1995, 1996, Li and Iwatsuki 2001, Ignatov et al. 2007, Purseil 2007). It further resembles F. dealbatus Hook. f. & Wilson from New Zealand, Australia and New Caledonia (Beever et al. 2002). Fissidens enervis differs from both by its cuspidate leaf apex. Fissidens hyalinus, is distinct from both F. enervis and F. dealbatus by its unistratose limbidia (Iwatsuki and Suzuki 1995). Fissidens dealbatus Hook. f. & Wilson differs from the other two species in having 40 or more columns of exothecial cells.
Fissidens enervis Sim, F. dealbatus and F. hyalinus belong to a remarkable group of Fissidens species that have subgenus Aloma sporophytes (hence they are classified in subgenus Aloma (Müll.Hal.) Kindb.), large laminal cells, ecostate to ± ecostate leaves and stems with lacking or weakly developed central strands (Pursell and Bruggeman-Nannenga 2004). Though occasionally ecostate species form dense mats they often grow sparsely scattered among other mosses. Unfortunately, all known collections of F. enervis are scanty.
Habitat and substrate: On land cuttings, exposed roots and soil in evergreen forest, associated with F. crispus Mont., F. crispulus and Philonotis hastata (Duby) Wijk & Margad. between 900 and 1200 m.
Distribution: South Africa, India, Western Ghats. Rare. Examined specimens: India, Kerala, Palakkad District (Nelliyampathy, 900–1200 m), 10°53′54″N, 76°69′36″E, 12.07.2015, Manjula K M (ZGC 1093 c, 1098 b, 1138 b).
Illustration: Magill 1981, Fig. 8: 1–7
The authors are thankful to the Dept of Science and Technology (DST-SERB), New Delhi, for the financial support. We are also thankful to the authorities of the Zamorin's Guruvayurappan College (ZGC), Kozhikode, for providing support and facilities. Thanks are also due to the officials of the Kerala Forest Department, for the permission and support extended during the field studies and to Dr. Maya C. Nair and Ms. Soumya of Department of Botany, Govt. Victoria College, Palakkad, for their help during the field trip. We are further obliged to the curator of PRE for the loan of the type specimen of F. enervis.