THE FERN GAZETTE Edited by BoAoThomas lAoCrabbe & Mo6ibby THE BRITISH PTERIDOLOGICAL SOCIETY Volume 14 Part 3 1992 The British Pteridological Society THE FERN GAZETTE VOLUME 14 PART 3 1992 CONTENTS Page MAIN ARTICLES A Revised List of The Pteridophytes of Nevis - B.M. Graham, M.H. Rickard 85 Chloroplast DNA and Morphological Variation in the Fern Genus Platycerium(Polypodiaceae: Pteridophyta) - Johannes M. Sandbrink, Roe/and C.H.J. Van Ham, Jan Van Brederode 97 Pteridophytes of the State of Veracruz, Medico: New Records - M6nica Pa/acios-Rios 119 SHORT NOTES Chromosome Counts for Two Species of Gleichenia subgenus Mertensiafrom Ecuador - Trevor G. Walker 123 REVIEWS Spores of The Pteridophyta - A. C. Jermy 96 Flora Malesiana - A. C. Jermy 123 The pteridophytes of France and their affinities: systematics. chorology, biology, ecology. - B. A. Thoinas 124 THE FERN GAZ ETTE Volume 14 Pa rt 2 wa s publis hed on lO Octobe r 1991 Published by THE BRITISH PTERIDOLOGICAL SOCIETY, c/o Department of Botany, The Natural History Museum, London SW7 580 ISSN 0308-0838 Metloc Printers Ltd .. Caxton House, Old Station Road, Loughton, Essex, IG10 4PE ---------------------- FERN GAZ. 14(3) 1992 85 A REVISED LIST OF THE PTERIDOPHYTES OF NEVIS BMGRAHAM Polpey, Par, Cornwall PL24 2T W MHRICKARD The Old Rectory, Leinthall Starkes, Ludlow, Shropshire SY8 2HP ABSTRACT A revised list of the pteridophytes of Nevis in the Lesser Antilles is given. This includes 14 species not previously recorded for the island. INTRODUCTION Nevis is a small volcanic island in the West Indian Leeward Islands. No specific li st of the ferns has ev er been pu blished, although Proctor (1977) does record each of the species known to occur on the island. Proctor's records were largely accumulated from herbariu m specimens collected by R A Howard in 1950 and hi s own collections in 1959. In total he recorded 81 taxa. Collections by one of us (BMG) in 1988 and both of us in 1990 have added a further 14 species plu s 3 unnamed species of Th elypteris and 4 established garden introductions. Nineteen species recorded in Pro ctor were not seen by either of us on the island. The 98 native or naturalised taxa here recorded for Nevis are still low in comparison with the nu mbe r recorded for the two larger pri ncipal neighbou ri ng islands of St Kitts: 129 (Proctor 1977) and Monserrat: 117 (Proctor 1977). Nevi s is approximately 6 mi les from east to west and 8 mi les from north to south, a total su rf ace area of 36 square mi les. The whole island is dominated by the central mou ntainous core rising to 3,23 2 feet at Nevis Peak. About 9, 000 people live on the island mostly arou nd the coastal plain and especially in the west near Charlestown, the Capital. The central mountainous area is unpopulated and rarely visited by the local inhabitants. The climate is tropical with the temperature rarely falling below 20°C. The prev ai ling wi nds blow from the south east wi th most rai nf all at hi gh altitudes (more than 100 inches annually), particularly to the north west of the su mmit peak. Here, clou d frequently hangs all day in the remnants of the su mmit crater protected from the prev ailing wi nds and occasional hu rricanes, e.g. hu rricane Hugo in 1989. Rainf all is low (less than 40 inches annually) in southern and eastern coastal areas where semi-desert scrub has developed. Rodriques (1990) has mapped the vegetation of the island (see Fig. l) and found that less than 4 squ are mi les (624 hectares) of montane type forest exi sts on Nevi s. He has fu rther su bdivided this area into three zones:- Montane forest - 500 hectares, Palm break - 115 hectares, Elfi n forest - 9 hectares. Montane forest wou ld be at an altitu de of about 1500-2300 feet, palm brake from 23 00- 27 00 feet and the elfin forest from 27 00-3 23 2 feet. At the time of the 1990 collecti ng mu ch of this forest, especially on the wi ndward si de of the island, was still recoveri ng from the damage cau sed by hu rri cane Hugo. Low altitude species - less than 1000 feet There are few ferns naturally occurring below 1000 feet. Exceptions are Acrostichum danaefolium in mangrove swamps at sea level, and ferns of walls and dry rocky areas, e.g. Cheilanthes microphylla, Anemia adiantifoliB, Pteris vittata and Pityrogramma calomelanos. Middle altitudes in dry evergreen forest- 1000-1500 feet In sheltered areas sev eral species tolerant of temporary drought are abundant, eg. Blechnum 86 FERN GAZETIE: VOLUME 14 PART 3 (1992) VEGETATION ZONES ON NEVIS L�i:ll DRY SCRUB WOODLAND -<RIPARIAN FOREST I:::::�:J DRY 'EVERGREEN' FOREST �!!� COCONUT PLANTATION t===3 MONTANE FOREST � MANGROVE WOODLAND rn CACT US SCRUB .ll1l1JI LIT TORAL WOODLAND QPALM BRAKE D URBAN,SUBURBAN AND AGRICULTVRAL � ELFIN WOODLAND FIGURE I. Vegetation zones of Nevis (after Rodriques, 1990). occidentale, Nephrolepis rivularis, Selaginella flabellata and on trees and ro cks Polypodium polypodioides, Polypodium aureum var. aureum and Polypodium lycopodioides. Montane forest - 1500-2300 feet Here tree-ferns are co mmon, usually Cyathea muricata and C.arborea, but occasionally in mo re sheltered areas at hi gher altitudes the mu ch smaller Cnemidaria grandifolia var. gr andifolia is frequent. The ground vegetation is ri ch in fer ns wi th Diplazium spp ., Tectaria incisa, Lonchitis hirsutus and many Th elypteris species lo cally do minant. The striking red yo ung fro nds of Adiantum latifolium are frequ ent in fo rest clearings and a problematical taxo n, probably also A. latifolium, occu rs occasionally on ro cks. In sheltered valleys on tree trunks and where rocks outcro p many species of filmy fern occur. Particu larly co mmon are Tr ichomanes membranaceum and Tr ichomanes alatum. Also on ro cks, bu t in mo re open si tes, Asplenium laetum, A. abscissum and A. cristatum occur occasionally, with in one co llection a problematical frond which might po ssibly be A.malcolm-smithii - believed endemic . to St Ki tts. Lomariopsis sorbifolia, Grammitis serrulata, Th elypteris reptans var. reptans, sev eral po lypo di aceous species and Vit taria Iineata also gro w occasionally on ro cks and trees. Domi nant flowering plants inclu de (after Ro driques, 1990) Sloanea truncata, Miconia spp, Dacryodes excelsa, Euterpe glo bosa, Beilschmeida pendula, Coccoloba pubescens, Aniba br acteata, Simarouba amara, Ceropia peltata and Podo carpus coriaceus. PTERIDOPHYTES OF NEVIS 87 Palm brake- 2300-2700 fe et In this zone several spec ies of palm ar e par ticularly common, dic ot yledonous trees also occur as do many ferns, although none appea r to be rest ricted to the palm break. All three tree-fern spec ies occur , Hym enophyllum hirtellum su bsp. gratum is abu ndant on many moss festooned trees together wi th Trichomanes alatum and T. crisp um. Also frequent are Polypodium Joriceum and Grammitis seminuda. Dominant spec ies of flowering plants (after Rodriques, 1990) are Euterpe gl obosa and Po docarpus coriaceus. FIGURE 2. Moss festooning branches in elfin forest. Elfin forest - 2700-3232 feet This zone is the jewel in the crown (See Fi gs. 2 & 3). In an are a perhaps only extending to 9 hectares seve ral of the more interest ing species are abundant. Gleichenia furcatata ngle d with Dicranopteris pectinata swamp many of the more exposed ridges and invade to some extent the tiny areas of su mmit he aths where Lycopodium cern uum var. dussii is common. In the de nse almost impenetrable forest all br anches, creeper s and tree trunks are thickly festoon ed with mosses, bromeliads and ferns. There appe ar to be no roc k faces as such and species from ge ne ra normally considered epipetric are common in these festoons, eg Hymenophy/Jum elegans, Grammitis scrrulata, G. flabelliformis and G. suspensa. Particularly conspicuous amon g these cpiphytic fe rns is Blechnum binervacum with it s arching fronds spirall ing from the thick sc aley rhizomes, climbing arou nd the stems of CyatiJea arborea. Also magnificent is the terrestrial Thelyptcris decussata with fronds up to 3 metres in le ngt h. Blec.hnum ryanii and Cnemidaria graadifolia var. grandifolia are abu ndant, while growing on the da rk fore st floorLindsaea quadrangularissu bsp. antillensisand Trichomanes trigonum var. trigonum are frequent . The fronds of this filmy fe rn grow erect to a he ight of 30 or 40 cm and are remarkably tough de spite their filmy nature. Less spec tacular, bu t of gr eater significance, is The/yp teris muscicola which occurs only rarely ri ght at the summit of Nevis Pe ak. This species grows nowhere else in the world. Dominant species of flowering plants (after Rodriques, 1990) are Euterpe glo bosa, Ficus sp ., Cli demia umbrasa and Po docarpus coriaceus. 88 FERN GAZETTE: VOLUME 14 PART 3 (1992) FIGURE 3. Cyathea arborea dominating the elfin forest at the summit. SPECIES LIST Most determinations have been confirmed by Dr Dennis Adams. Species recorded in Pr octor (1977) have been incorpor ated to give a list of the ferns of Nevis as comprehensive as possib le at the present time. Or der and nomencl ature is usually as in Fl ora of the Lesser Antilles - Pt eridophyta (1977) by G R Proctor . Where differ ent, old names are given in brackets. Common names are taken from Jones (1987). Entries of introduced species are preceded by an *.