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FERN GAZ. 15(2)1995 41

STUDIES ON INTRASPECIFIC VARIATION IN SOUTH INDIAN
FERNS: REDISCOVERY OF THE RARE DIPLOID CYTOTYPE OF
CHRISTELLA PARASITICA (THELYPTERIDACEAE:
PTERIDOPHYTA)

V. IRUDAYARAJ, S. DOMINIC RAJKUMAR and V.S. MANICKAM
St. Xavier’s College, Palayamkottai, Tamil Nadu, India - 627 002.

Key words: Cytotype, Christella parasitica, morphology, south India.

ABSTRACT

During cytological study of the Christella parasitica complex in south India, we
discovered the rare diploid cytotype (n = 36) from Kothayar, Tirunelveli Hills (900 m) and
from Kodaikanal, Palni Hills (1,700 m) in the Western Ghats of south India along with the
common tetraploid cytotype. The diploid and tetraploid cytotypes from both localities
mentioned above are compared morphologically. The identity of the diploid taxon is also
discussed.

INTRODUCTION

The Western Ghats in India are a region with a rich and diverse flora which has excited many a
botanist and continues to do so (Nair & Daniel 1986). The publications by Abraham et al
(1962), Bhavandan (1968, 1981), Kuriachan (1968, 1976, 1978), Sankari Ammal and
Bhavanandan (1988, 1989, 1990, 1991 a,b,c, 1992), Bir and Vasudeva (1979), Manickam
(1986), Manickam and Irudayaraj (1988, 1989 a), Irudayaraj and Manickam (1987), Irudayaraj
et al. (1993) on cytology and by Manickam (1986), Manickam and Irudayaraj (1989 b, 1990,
1992) and Nayar and Geevarghese (1993) on taxonomy of south Indian ferns, clearly indicate
that approximately 20% of the south Indian ferns are highly variable morphologically or
cytologically. This suggests a high degree of diversity in the fern flora in this region. In order
to understand the degree of diversity and frequency of distribution of variants within species
complexes in the region, a long term study of intraspecific variation in south Indian ferns has
been initiated. As a first step study of morphological variation in Christella parasitica (L.) Lév.
was carried out by Irudayaraj (1991). The present paper reports the results of cytological study
of this species complex.

The thelypteroid genus Christella Lév. which contains approximately 50 species, occurs
predominantly in the old world tropics but also in the Americas (Holttum 1976). C. parasitica
is acommon fern in south India (Manickam & Irudayaraj 1990, 1992). It has also been reported
from south China, Taiwan, Ryukyu Island (south Japan), north east and south India, Nepal, Sri
Lanka, Thailand, Vietnam, Malesia, Queensland (N. Australia), Fiji, Samoa, New Caledonia,
Cook Island, Austral Island, Tahiti, Hawaii, Uganda, Kenya and St. Helena (Holttum 1976). It
is a highly variable species as regards the length of hairs and presence or absence of glandular
hairs and is also variable in cytotype. Cytological reports of the species from various
geographical regions show that tetraploids are common and _ diploids very rare (Table 1).
Reports from south India (Abraham et al 1962, Bhavanandan 1981, Irudayaraj & Manickam
1987, Manickam & Irudayaraj 1988, 1989 a) have revealed the presence of diploid and
tetraploid sexual cytotypes and a triploid sterile hybrid in this complex. Of these, the only report
of a diploid cytotype for the whole of India was by Manickam and Irudayaraj (1988) from
Kothayar, Tirunelveli Hills. (Rapinat Herbarium, Tiruchirapalli 32008, identified as C.
parasitica by the late Prof. R.E. Holttum, pers. comm), though a diploid has also been reported
from Taiwan by Tsai & Shieh 1986). During the present study we have found the diploid
cytotype at Kothayar again and also at Kodaikanal, Palni Hills, south India (Fig. 1).

42 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Interestingly we found that the tetraploid cytotype also occurs with the diploid in both localities.
We have now compared both cytotypes in detail morphologically.

Figure 1. Physical map of south India showing the Palni Hills and Tirunelveli Hills.

Table 1

Chromosome numbers for Christella parasitica from different geographical regions.

Locality Chromosome References
number (‘n’)

South India 36 Irudayaraj & Manickam
(1987), Manickam &
Irudayaraj (1988).

2, " a
v2 Abraham et al (1962),
Bhavanandan (1981)
W. peninsular India 2: Mahabale & Kamble (1981)
C. India 72 Vasudeva & Bir (1983)
W. Himalaya FZ Punetha (1989)
Sri Lanka A2 Manton & Sledge (1954)
Malaya 72 Manton (1955)
Japan 72 Kurita (1976)
Mitui (1975)
Taiwan 36 Tsai & Shieh (1986)
TP f +

V2 Vida & Major (1987)

DIPLOID INDIAN CHRISTELLA PARASITICA 43

MATERIALS AND METHODS

Plant material for the present study was collected from Kothayar, Manjolai-Kakachi road,
Tirunelveli Hills (900 m.) and from Kodaikanal, Palni Hills (1,700 m.), both in Tamil Nadu. All
the materials from Kothayar was obtained from the field while the Palni Hills material was
obtained from plants raised in cultivation from rhizomes from that source at Palayamkottai. For
cytological studies sori of plants from Kothayar were fixed in the field in a mixture of absolute
ethanol, chloroform and glacial acetic acid (6:3:1) and were similarly fixed from plants
cultivated for four months from the Palni Hills. For chromosome counting the standard
acetocarmine squash technique (Manton 1950) was followed. Micromorphological characters
were studied using a binocular and compound light microscope. Herbarium voucher specimens
are deposited at XCH (St. Xavier’s College Herbarium, Palayamkottai, India).

OBSERVATIONS
The diploid (n=36) and tetraploid (n=72) cytotypes were examined cytologically and thirty six
and seventy two regular bivalents were observed in the spore mother cells of each cytotype
respectively (Figs 2 a-d). In all the individual plants examined the sporangia are filled with 64
normal spores which confirms their sexual nature.

Figure 2. Spore mother cells of diploid plants and explanatory drawings from the Palni Hills (a,
b) and Tirunelveli Hills (c,d) showing 36 bivalents in each cell. The scale-marker equals 10um.

44 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Figure 3. Silhouettes of basal parts of fronds of tetraploid forms of C. parasitica from the Palni
Hills (a) and Tirunelveli (b) (scale bar = 30 mms)

DIPLOID INDIAN CHRISTELLA PARASITICA 45

Figure 4. Silhouettes of basal parts of fronds of diploid forms of C. parasitica from the
Tirunelveli Hills(a) and Palni Hills(b) (scale bar = 30 mms).

46 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Macro- and micro-morphological characters of the two diploids and two tetraploids are
tabulated in Table 2. None of the plants have reduced basal pinnae except the Palni Hills
tetraploid cytotype in which the lowest basal pair is slightly reduced (Figs 3,4). The rhizome in
both Palni Hills cytotypes is erect while it is shortly creeping in both cytotypes from Kothayar.
Orange coloured glands are very common on the under-surface of the costules and veins in the
tetraploid plant from Kothayar, but they are totally absent in all the others. Concerning the
spore-size and stomatal guard-cell size there is a considerable difference between the diploid
and tetraploid cytotypes (see Table 2).

Figure 5. Silhouettes of pinnae from different populations of C. parasitica A(4x) and B(2x)
from the Palni Hills. C(4x) and D(2x) from the Tirunelveli Hills.

Figure 6. Photographs from a portion of under surface of a pinna lobe from different populations of C.
parasitica showing the distribution of hairs. a(2x) and c(4x) from the Palni Hills. b(2x) and d(4x) from
the Tirunelveli Hills.

DIPLOID INDIAN CHRISTELLA PARASITICA 47
Table 2

Morphological features of the different cytotypes of Christella parasitica

Voucher specimen number XCH! 3340 XCH 3350 XCH 3341 XCH 3357
and locality Palni Hills Tirunelveli Hills Palni Hills Tirunelveli Hills
Chromosome number (‘n’) 36 36 72 72,
Rhizome Erect Short creeping Erect Short creeping
Lamina size (cm) 48 x 24 39 x 25 39 x 18.5 38 x 16
Total number of pairs of pinnae 15 18 1] 17
Reduced basal pinnae No No One pair slightly No

Pinna size (cm) [Dox 2: Lixo? 10.5 x 2 15ax, U5
Depth of lobing of pinnae 3/4 way to costa 2/3 1/2 2/3

(Fig. 5)

Anastomosing veins | pair | pair | pair | pair
Orange coloured glands No No No Many
Spore size (um) Sh6% 21-4 34.5 x 22.42 43.3 x 24.7 44.3 x 29.9
Guard cell size (um) 253075 2G XK S20 BD Agee 26.5 x 9.1
Pubescence (Fig. 6)

On Lamina Upper surface Long, sparse Long, dense Long, dense Long, sparse

On costa
Lower surface

Upper surface

On costules
Lower surface

Upper surface

On veins
Lower surface

Upper surface

On intervenal area

Lower surface

On indusia

Long and short rare

Long, rare

Long and short rare

Short, rare

Short, rare
Glabrous

Glabrous

Short, dense

Long and short sparse

Long, occasional

Long and short sparse

Long, rare

Short, sparse
Glabrous

Short sparse

Long, dense

Short, sparse

Long, rare

Short, sparse

Long, rare

Short, sparse

Minute, sparse

Short, dense

Short, dense

Long occasional

Long, rare

Long occasional

Long, rare

Long, occasional

Short, rare

Long, dense

Long, dense

| XCH = St. Xavier’s College Herbarium, RHT = Rapinat Herbarium, Tiruchirapalli.

2 The measurement is from the diploid cytotype (RHT! 32008, see Manickam & Irudayaraj 1988)

from the same locality. There are no mature sori in the present material.

48 FERN GAZETTE: VOLUME 15 PART 2 (1995)

DISCUSSION

Diploid plants of the Christella parasitica complex from Sri Lanka, Borneo, Nigeria and Ghana
are closely similar morphologically and are interfertile. They belong to a somewhat distinct
species, C. hispidula (Decne) Holttum (Holttum 1976, Manton & Sledge 1954, Sledge 1981).
However all four collections mentioned in the present study clearly belong to C. parasitica. C.
hispidula has an erect rhizome and 2-4 pairs of gradually shortened basal pinnae, but the diploid
cytotype from the Palni Hills, though having an erect rhizome has_ unreduced basal pinnae.
Although C. parasitica normally has a creeping rhizome an erect one is not uncommon
(Manickam 1986).

The discovery of a diploid cytotype from south India (and Taiwan) presents a most
interesting possibility in our understanding of the interrelationships between members of the
complex as the tetraploid cytotype has been shown to be an allotetraploid originating from C.
hispidula (2x) and another, unknown, diploid parent (Panigrahi & Manton 1958, Ghatak et al.
1971). The relationship of the present diploid cytotype of C. parasitica with other members of
the complex is as yet unknown, but since a “missing” diploid is known to have been involved
in the group it would be of great interest to attempt hybridisation and genome-analysis involving
the present taxon to find out if it could be the “missing” ancestral diploid, which would seem at
least a strong possibility.

In another polymorphic species of Christella, C. papilio (Hope) Holttum, the diploids have
an erect rhizome and the tetraploids (var. repens Sledge) have a creeping rhizome (Manton &
Sledge 1954). However we have found that in C. parasitica the rhizome-type and ploidy level
do not coincide consistently. Thus both diploid and tetraploid cytotypes from the Palni Hills
have an erect rhizome. The same is true of other morphological characteristics. From the
polygraphs (Fig. 7) it is clear that the present gatherings could not be segregated
morphologically either on the basis of locality or ploidy level. It is suggested that further
experimental studies be undertaken in order to investigate the interrelationships between the
present diploid cytotype and other cytotypes in this species complex.

Figure 7. Polygraphs of different populations of C. parasitica. a(2x) and c(4x) for the Palni
Hills cytotypes. b(2x) and d(4x) for the Tirunelveli Hills cytotypes.

A - Lamina length, B- Number of pairs of pinnae, C - Pinna length, D- Pinnule length, E -
Depth of lobing, F - Spore length, G - Guard cell length, H - Degree of pubescence.

DIPLOID INDIAN CHRISTELLA PARASITICA 49

ACKNOWLEDGEMENTS
We are deeply grateful to Rev. P.J. Ubelmesser s.j., Nurnberg, Germany and Rey. Hubert
Hanggi, Ziirich, Switzerland for financial assistance to carry out the present project on the ferns
of the Western Ghats of south India.

REFERENCES

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BIR, S.S. & VASUDEVA, S.M. 1979. Cytological studies on some ferns of Kodaikanal,
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IRUDAYARAJ, V., BIR, S.S. & MANICKAM, V.S. 1993. Cytology of ferns from the
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KURIACHAN, P.I. 1976. Cytological studies of two species and a triploid hybrid of
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69-76.

MAHABALE, T.S. & KAMBLE, S.Y. 1981. Cytology of ferns and other Pteridophytes of
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MANICKAM, V.S. 1986. The fern flora of Palni Hills, south India. Today & Tomorrow’s
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MANICKAM, V.S. & IRUDAYARAJ, V. 1988. Cytology of ferns of the western Ghats, south
India. Today & Tomorrow’s Printers and Publishers, New Delhi.

MANICKAM, V.S. & IRUDAYARASJ, V. 1989 a. Corrections to the “Cytology of ferns of
the western Ghats, south India’. /ndian Fern J. 6 (1-2): 131-132.

MANICKAM, V.S. & IRUDAYARAJ, V. 1989 b. Thelypteridaceae (Ferns) in the western
Ghats of south India. Abst. Vol. of ‘Flora Malesiana’ Symposium, Leiden, 20-25
August. 1989. 45-46. Leiden.

MANICKAM, V.S. & IRUDAYARAJ, V. 1990. Thelypteridaceae of the western Ghats of
south India. Jndian Fern J. 7(1-2): 100-117.

50 FERN GAZETTE: VOLUME 15 PART 2 (1995)

MANICKAM, V.S. & IRUDAYARASJ, V. 1992. Pteridophyte flora of the western Ghats-
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Singapore.

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NAIR, N.C. & DANIEL, P. 1986. The floristic diversity of the western Ghats and its
conservation: A review. Proc. Indian Acad. Sci. (Anim. Sci./Plant Sci.) Suppl.: 127-
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NAYAR, B.K. & GEEVARGHESE, K.K. 1993. Fern Flora of Malabar. Indus Publishing
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PANIGRAHI, G. & MANTON, I. 1958. Cytological and taxonomic observations on some
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PUNETHA, N. 1989. Cytological observations on ferns of Kumaon (N.W. Himalayas), in
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SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1988. Cytological studies on a hybrid
species of Trichomanes L. Indian Fern J. 5(1-2): 176-179.

SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1989. Cytological studies on Blechnum
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SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1990. A note on the cytology of
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SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1991 a. Cytological studies on the genus
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family Aspidiaceae (sensu Copeland) from south India. /ndian Fern J. 8(1-2): 78-86.

SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1991 c. Studies on the cytology of some
members of Polypodiaceae (sensu Copeland). Indian Fern J. 8(1-2): 154-158.

SANKARI AMMAL, L. & BHAVANANDAN, K.V. 1992. Studies on the cytology of some
ferns from south India. /ndian Fern J. 9(1-2): 113-118.

SLEDGE, W.A. 1981. The Thelypteridaceae of Ceylon. Bull. Brit. Mus. Nat. Hist. (Bot.)
8(1): 1-54.

TSAI, J.L. & SHIEH, W.C. 1986. A cytogeographic study of the fern genus Cyclosorus in
Taiwan. J. Sci. Engin. (Taiwan) 23: 83-106.

VASUDEVA, S.M. & BIR, S.S. 1983. Chromosome numbers and evolutionary status of
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FERN GAZ. 15 (2)1995 51

TUNBRIDGE FILMY-FERN HYMENOPHYLLUM
TUNBRIGENSE (HYMENOPHYLLACEAE:
PTERIDOPHYTA) IN SOUTH EAST
ENGLAND IN 1994/1995

TEG: RICH
The Annex, Newgale Farm, Priory Road, Forest Row, East Sussex, RH18 5JD

S.J. RICHARDSON
Syndal, Romford Road, Pembury, Kent, TN2 4BB

F. ROSE
Rotherhurst, 36 St. Mary’s Road, Liss, Hampshire, GU33 7AH

Key words: Fern, Hymenophyllum tunbrigense, England.

ABSTRACT
The sites of Tunbridge filmy-fern (Hymenophyllum tunbrigense (L.) Smith) in south-east
England were surveyed in 1994/1995 and the population sizes counted. An analysis of
regeneration shows low recruitment in recent years, and another catastrophic event sometime
between 1953 and 1963. The fern was fertile except in densely shaded sites, and
gametophytes were observed in one site. 24 colonies were found in twelve sites, and it was
extinct in eight sites. A comparison with data collected in the 1950s/early 1960s indicates a
decline of 20% in the number of sites and a 68% decline in the number of colonies. The
decline is due to a combination of loss of woodland cover, dense shade especially from
rhododendron, and storm damage; historically collecting and public pressure have also
caused losses. The fern is under threat in south-east England as half the sites have only one

surviving patch.

INTRODUCTION

The Great Storm of 1987 and a second storm in 1990 caused widespread devastation in
woodlands in south-east England (e.g. Kirby & Buckley 1994). Tunbridge filmy-fern
(Hymenophyllum tunbrigense (L.) Smith) is one of a number of western oceanic or Atlantic
species most frequent on the west coast of Britain which are also found in the mild, damp
climate of the Weald in Sussex and Kent (e.g. Dryopteris aemula, Wahlenbergia hederacea;
Rose 1952). It is characteristic of steep, porous sandstone rock faces usually surrounded by
deciduous woodland with a particular microclimate, and it often grows with Atlantic bryophytes
(Pentecost & Rose 1985). It is generally considered intolerant of too much exposure (Richards
& Evans 1972) and would be expected to be sensitive to large scale canopy loss such as that
caused by the storms. However, searches in 1988, the year after the Great Storm, found the fern
undamaged and “fallen trees had let in light which had apparently benefited Hymenophyllum at
some sites, as at West Hoathly and Eridge Rocks” (Briggs 1990). Ecological processes are often
slow and complex in expression, and the short-term benefits may be counter-acted by less
suitable longer term changes, or subsequent irregular catastrophic events such as severe drought
or heat waves.

Historically Tunbridge filmy-fern has been recorded in about 20 localities in south-east
England (Fig. 1). It was first found in south-east England by G. Dare (Evans & Jermy 1962),
and by the 1900s was known in at least 12 sites. Six further sites were found after the Second
World War by F. Rose and E. C. Wallace, who by the early 1950s knew about 10 sites scattered

52 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Fig. 1. Location of sites of Tunbridge filmy-fern in south-east England

across the Weald (Rose 1952). The first detailed documentation of the filmy-fern by Comyn
(1953)(now Mrs. J. Paton) was carried out during ecological studies of the sandrocks in the
Weald. She described it as abundant at Philpots, fairly abundant at Tilgate, Wakehurst and
Chiddinglye, and at Eridge and Cow Wood. There were “good” colonies at Balcombe Mill and
Rocks Wood at Mott’s Mill, whilst at Penns in the Rocks and at Harrison’s Rocks there were
only single, small patches. Pentecost and Rose (1985) recorded it in nine sites between 1981
and 1984 and noted that it had disappeared from two sites historically (Harrison’s and High
Rocks), but concluded that no decline was apparent then at the remaining sites.

The aim of this paper is to present the results of a field survey in 1994/1995 of the Tunbridge
filmy-fern in south-east England to assess the status of the plant a few years after the storms.
There is also a need to clarify that some of the records additional to the Sussex Plant Atlas (Hall
1980) given in the Selected Supplement (Briggs 1990) were old records of F. Rose and were not
new finds; indeed some were already extinct. Some records in Pentecost & Rose (1985) also
require correction.

METHODS
Records were collated from the literature, herbarium specimens (BM, BTN, K, LIV, OXF, TLS
and WAR) and correspondence with other botanists. Some vague old records have been
correlated with known sites as it is uncertain or even sometime impossible to establish to which
site they actually refer.

All known sites were visited in 1994 or 1995 by SJR and/or TCGR at least twice (and some
six times). Within each site, the number of Hymenophyllum patches in each colony was noted.
A patch was defined as an individual plant physically separate from its neighbours. Some
patches were obviously clones resulting from disintegration of a larger patch but were none-the-
less recorded as separate patches, and it is also possible some larger patches may be composed
of more than one individual where plants have grown together. A colony may be composed of
one or more patches; it was generally easy to distinguish different colonies within sites as they
were physically separated from each other by the rock formations.

The maximum length and width of each patch within each colony was measured and details
of its situation (aspect, slope, summer canopy cover) were estimated. The canopy species, storm
damage and the general situation of the rock outcrops were also noted. Ancient woodland status

TUNBRIDGE FILMY-FERN IN SE ENGLAND 58

has been taken from the inventories of ancient woodland (Whitbread, Barton & Hutton 1984a,
1984b; Pritchard et al. 1994) updated from the field work.

Soil samples were taken from the base of the outcrops to provide an estimate of the pH of
the rooting substrate. Soil pH was measured by mixing dried or fresh soil samples to a thick
slurry with de-ionised water (approximately equal volumes of soil and water), and measured
with a Hanna Piccolo ATC pH-meter calibrated against standard buffer solutions.

Site names are taken from the 1:25,000 Ordnance Survey Pathfinder maps. Scientific and
English nomenclature of vascular plants follows Stace (1991); lower plants names are given
with authorities.

RESULTS
Distribution
A total of twenty sites have been identified from the literature, herbarium and field survey; full
details including site photographs and maps have been deposited in the Natural History Museum
(Richardson, Rose & Rich 1995), and are briefly summarised here. All the records are from V.c.
14 with two exceptions noted below.

1. Cow Wood, Handcross (TQ/2.2) was first reported “plentiful on a rock called Pook Church”
by J. Henness Jnr. (Luxford 1838). Newman (1854) described it as abundant. Arnold (1887)
gave two localities which probably refer to the same site; “near Handcross” by W. Borrer,
and again “on a rock called Pook Church” by E. C. De Crespigny. It has been regularly
recorded at this site since (e.g. Wolley-Dod 1937; Hall 1980; Pentecost & Rose 1985).

2. Northland Wood (TQ/2.2) was first found by F. Rose in 1962, but was overlooked in Hall
(1980).

3. Pilstye Wood (TQ/3.2). Lloyd and McEnnes (1852) reported the filmy-fern near Balcombe
on an excursion in Tilgate Forest. They were ambiguous about its exact location but they
refer to rocks in a copse a mile south of Balcombe which we assume refers to this wood but
could also refer to Balcombe Mill.

4. Balcombe Mill (TQ/3.3) was first reported by Comyn (1953). It was not included in Hall
(1980), later amended in Briggs (1990).

5. Tilgate Wood (TQ/3.3). Records for Ardingly Rocks are assumed to refer to this and the
following four sites (especially Chiddinglye / Philpots). It appears to have been first
recorded in the Ardingly area by W. Borrer (Turner & Dillwyn 1805), and was described as
abundant by Newman (1854). It was seen for the first time categorically in this site by F.
Rose and E. C. Wallace in 1947.

6. Paddockhurst Park (TQ/3.3) is assumed to be the site recorded as rocks at Turners Hill by W.
E. Nicholson in 1903 (Salmon 1906; Arnold 1907). The filmy-fern was recorded by F. Rose
in 1954 up to about 1960 (the 1981-1984 record in Pentecost & Rose 1985 is an error).

7. West Wood, Wakehurst Place (TQ/3.3). It is unclear which historical records refer to this site
or Tilgate Wood (cf. above). The first unambiguous record from this site was by F. Rose in
1947 (three sites).

8. Hapstead, Ardingly (TQ/3.2). The record for this site is based on a herbarium specimen
“from the rocks near Apstead, Sussex”, F. J. Young, 1834 (BM). We have been unable to
trace Apstead, but the name is so similar to Hapstead in an area where the fern has been
known for many years it is assumed that this is the locality.

Chiddinglye Wood and 911. Philpots (TQ/3.3). Historical records may refer to either
Chiddinglye Wood (also known as Walls Wood or Stonehurst) or Philpots (also known as
Rocks Wood or Rockhurst, or perhaps even Ardingly Rocks), or both. The earliest record
for this site is probably one of E. Forster (BM) but the herbarium specimen is undated.

91.

_

54

10.

Ike

16.

FERN GAZETTE: VOLUME 15 PART 2 (1995)

There are later records by W. Borrer “rocks near West Hoathly” in Turner & Dillwyn (1805),
W. H. Coleman in 1836 (Rich 1994), Lloyd & McEnnes (1852), “abundant in August 1853”
(Newman 1854) and C. E. Salmon in 1890 (Arnold 1907). One specimen collected in 1838
from “Chiddingly Wood near Pearceland” (BM) may have been from the western side of the
wood.

Furnace Wood, Fairwarp (TQ/4.2) was first found by F. Rose inc. 1955. D. Streeter has
reported plants in Rocks Woods on the opposite side of the valley to Furnace Wood.
Jockey’s Wood (TQ/5.3) is near to the following site, and it is unclear to which the historical
records refer. Hymenophyllum was first recorded from Penns in Forster (1801), and the
records were repeated in Turner & Dillwyn (1805) and presumably by Wolley-Dod (1937).
It is also assumed that the record for Withyham by W. Borrer in Turner & Dillwyn (1805)
belongs to this site (or one of the other associated sites at Mott’s Mill) which is within the
parish of Withyham (C. A. Stace, pers. comm. 1994). The tetrad record was not published
in Hall (1980) but was included in the supplement although it was already extinct (Briggs
1990).

. Penns in the Rocks (TQ/5.3) was first definitely recorded by J. Wallis in 1943 but has not

been seen since.

. Rocks Wood, Mott’s Mill (TQ/5.3) was first found by F. Rose in 1948. A second colony

near 14. Leyswood (TQ/5.3) was first found by M. Rickard in 1962. It was recorded in Hall
(1980) and erroneously deleted from the supplement (Briggs 1990).

. Penshurst (V.c. 16; TQ/5.4). Hanbury & Marshall (1899) recorded that the filmy-fern was

“reported from Penshurst by Mr. John Cox”. John Cox lived at Redleaf north of Penshurst,
but none of his specimens have been traced. The original site is unknown, but suitable
outcrops occur at Redleaf House, The Grove and elsewhere around Penshurst. Mr E. Philp
(pers. comm. 1995) has pointed out that some lists included in Hanbury & Marshall (1899)
were compilations given one locality name where the botanist lived (e.g. Miss Petley’s
records from Sutton Valence) and may not all actually have been at that site; the
Hymenophyllum record could therefore refer to the High Rocks area. There are about 60
records by Cox in Hanbury & Marshall (1899), and the locality mysteriously changes from
Redleaf to Penshurst half way through the flora suggesting that the list may indeed have
been recognised as one general list. However, all of the species are quite likely to have been
found in the immediate area around Penshurst and some notable species from well-known
localities nearby are not amongst those mentioned, so the list may indeed have been for
Penshurst. As there are suitable sites for Hymenophyllum in the Penshurst area we currently
accept the record.

Harrison’s Rocks (TQ/5.3) was first recorded by Forster (1801). F. Rose recorded two weak
patches in 1950 (erroneously reported as extinct by the 1940s by Pentecost & Rose 1985).

. Eridge Rocks (TQ/5.3) was first definitely recorded by W. Borrer (Turner & Dillwyn 1805),

but it is likely that the record in Forster (1801) for “.. Harrisons Bridge ..” should read “..
Harrisons, Eridge ..”. Bennett (1851) recorded it in two places. It was later recorded by E.
Jenner (Arnold 1887) and was seen here by A. H. Wolley-Dod himself in 1935 (BM;
possibly the same record as 1936 in Wolley-Dod 1937). The record for “rocks in Eridge
Park” by W. Pamplin in 1837 (Wolley-Dod 1937) is assumed to belong to this site, but could
also refer to rocks in Eridge Park itself (no filmy fern occurs on these rocks now). It was
over-looked in 1981-1984 by Pentecost & Rose (1985).

. High Rocks (TQ/5.3) was first recorded by G. Dare in 1686 (Ray 1686) but the first definite

record was by Petiver (1714). Records for Tonbridge, Tunbridge, and Tunbridge Wells are
assumed to refer to this site. It was recorded by Forster (1801), and by many others
subsequently. Bennett (1851) recorded it in two sites at High Rocks, and noted in one that

TUNBRIDGE FILMY-FERN IN SE ENGLAND ao

19.

20.

large dead masses of the fern (some patches “certainly a yard square’) were found in the
bottom of a fissure which had been “ruthlessly torn off the rocks and left to perish ... by
some Goth or Vandal”. Newman (1854) recorded it as “formerly most abundant...but large
masses of it have been rolled off the rocks like blankets, insomuch that it is now found
sparingly”. The last record traced which may refer to this site is one collected in 1865 by
H. E. Fox (OXF). Wolley-Dod (1937) noted it to have been extinct here since at least 1875,
and it may have been collected out during the Victorian fern craze.

Hungershall Rocks (V.c. 16; TQ/5.3). Hanbury & Marshall (1899) list “High Rocks, etc.”
as a locality, and quite clearly accept the plant for Kent. Again the records are somewhat
ambiguous, but a record for “just within the limits of the county (i.e. Kent), at Tunbridge
Wells” (Newman 1854) probably refers to Hungershall Rocks (Stace 1962). Newman
clearly knew where the county boundary was, and the rocks are eminently suitable habitat
adjacent to a classic locality.

Saxonbury Hill (TQ/5.3) was first recorded as plentiful on sandrocks at Saxonbury Hill by
Rose (1953).

In 1994/1995, the filmy-fern was recorded in twelve sites and was extinct in eight (Table 1)
representing a probable 40% decline overall. None of the transplants of Hymenophyllum
wilsonii or H. tunbrigense (Comyn 1953, Evans 1962; Stace 1962) have survived.

Table 1. Dates of first and last records of Tunbridge filmy-fern in south-east England.

SITE FIRST RECORD LAST RECORD

1. Cow Wood 1838 1994
2. Northland Wood 1962 1994
3. Pilstye Wood 1852 1852
4. Balcombe Mill [953 1994
5. Tilgate Wood 1805 1994
6. Paddockhurst Park 1903 1960
7. West Wood 1947 1994
8. Hapstead 1834 1834
91. Chiddinglye Wood 1805 1994
911. Philpots Farm 1805 1994
10. Furnace Wood L955 1994
11. Jockey’s Wood 1805 1953
12. Penns in the Rocks 1943 1943
13. Rocks Wood 1948 1995
14. Leyswood 1962 1994
15. Penshurst pre 1899 pre 1899
16. Harrison’s Rocks 1801 1953
17. Eridge Rocks 1801 1994
18. High Rocks 1686 1865
19. Hungershall Rocks 1854 1854
20. Saxonbury Hill 1953 1994

An invaluable documentation of many population sizes was included in Mrs. J. Paton’s

M.Sc. thesis (Comyn 1953), which, combined with field notes of F. Rose and others, has
allowed a detailed comparison of the number of colonies in the 1950s/early 1960s with those in
1994/1995 (Table 2). The data show that since the 1950s/early 1960s, there has been an
estimated 68% decline in the number of colonies and 20% loss of sites.

56 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Table 2. Population sizes of Tunbridge filmy-fern in the 1950s/ early 1960s and 1994/1995 in
south-east England.

SITE Comyn (1953)/ *ROSE No. colonies (No.

(as above to 1962) patches) in 1994/1995
1. Cow Wood Several good colonies 1 (5)
2. Northland Wood 2 patches (*1962) dy)
3. Pilstye Wood Extinct (*) Extinct
4. Balcombe Mill 1 good patch 3p)
5. Tilgate Wood 4+ patches 8 (Cl)
6. Paddockhurst Park 2 patches (*1954) Extinct
7. West Wood 3 colonies 1 (1)
8. Hapstead Extinct (*) Extinct
91. Chiddinglye Wood Several good patches 1 (4)
911. Philpots Farm 50 patches/colonies 7 (24)
10. Furnace Wood 1 patch (*1955) 1 uy)
11. Jockey’s Wood 1 small patch Extinct
12. Penns in the Rocks Extinct Extinct
13. Rocks Wood 1 good patch Ik (WU)
14. Leyswood M. Rickard 1962 1 (1)
15. Penhurst Extinct Extinct
16. Harrison’s Rocks 1 minute patch Extinct
17. Eridge Rocks 4 good colonies (8*) 3 (10)
18. High Rocks Extinct Extinct
19. Hungershall Rocks Extinct Extinct
20. Saxonbury Hill 6 patches in 2 colonies IC)
Number of sites with filmy-fern 5 2
Number of colonies 76 24
Number of patches (data not precise) V1
Habitat

The filmy-fern grows on the sandrocks or Ardingly Sandstone which is a massive, cross-bedded,
fine-grained, quartzose, poorly cemented sandstone, which form most of the conspicuous
outcrops in the Tunbridge Wells - East Grinstead - Balcombe - Ardingly area. It is part of the
Lower Tunbridge Wells Sand (Bristow & Bazley 1972). Robinson & Williams (1981; 1984)
give very readable accounts of the geology and geomorphology of the sandrocks in the Weald.

The pH of the sand taken from the base of the rocks (assumed to be equivalent to the fern
rooting medium) is shown in Table 3. The pH of sand from a recently detached patch of filmy-
fern from one site was measured as pH 3.2, which agrees well with the soil measurements. The
pH of newly exposed sandstone was pH 5.1. The rooting medium is therefore assumed to be
highly acidic, ranging from pH 2.9-3.8. Richards & Evans (1972) noted it occurs most often on
acidic rocks but give no pH values for comparison.

The filmy fern has rarely been recorded growing as an epiphyte in the Weald. One specimen
collected by J. Clarke at Ardingly (probably the Chiddinglye complex) in 1860 (K) was growing
attached to pine bark. F. Rose observed plants in the 1950s growing on the bark of either birch
or beech near Great upon Little, Chiddinglye.

It mainly occurs on vertical rock faces, sometimes under overhangs (i.e. where the angle of
slope is greater than 90 degrees) and less commonly on sloping boulders (Figure 2). This
pattern probably reflects the predominance of vertical rock faces rather an ecological preference

TUNBRIDGE FILMY-FERN IN SE ENGLAND

a7

Table 3. Soil pH at sites for Tunbridge Filmy-fern in 1994/1995.

SITE SOIL pH
1. Cow Wood 3.8

2. Northlands Wood 2.9

4. Balcombe Mill Se)

5. Tilgate Wood 3.2, 3.4
7. West Wood 3.8

91. Chiddinglye Wood 333

911. Philpots Farm 2.9.3.4
10. Furnace Wood 3.3

14. Leyswood 21)

17. Eridge Rocks Ss)
20. Saxonbury Hill 3.6

for vertical situations. An analysis of sites in 1994/1995 shows plants occur at varying heights
from the ground (data not presented), confirming the observations for the Weald in Richards &
Evans (1972).

20

Frequency 10

0 30 60 90 120 15

Slope (degrees from horizontal)

Fig. 2. Bar chart showing relationship between number of patches of Tunbridge filmy-fern
and slope in south-east England in 1994/1995

The fern also occurs on all aspects (Figure 3) and does not seem to occur in predominately
north-facing sites as implied by Evans (1964). There is a general correlation between aspect and
canopy cover (Figure 3) and plants only occur in south-facing situations where they are shaded.

The most frequent associated species forming the canopy above were holly, rhododendron
and silver birch (Table 4). Holly and yew are often more frequent on the sandrocks than in the
surrounding woodlands.

Regeneration

The reproductive cycle has been described by Richards & Evans (1972), and only a few extra
observations are included here. In October 1994 many patches in reasonably well-lit places
were observed with open indusia revealing the golden sporangia inside though none had
dehisced at that stage (plants in dense shade were rarely fertile). Three months later, sporangia
had dehisced so gametophytes were searched for resulting in about discovery of about 15 thalli,
all with 1-4 young leaves, in a shaded site at Philpots. The gametophytes occurred about 50 cm
east (i.e. downwind in the prevailing south-westerly winds) of established patches.

58 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Fig. 3. Aspect and canopy cover for each colony of Tunbridge filmy-fern in south-east
England. Aspect is indicated by the location of the circle, and the canopy cover is shown by
the percentage shaded (open = 0% canopy, closed = 100% canopy)

Table 4. Vascular plant species forming canopy over colonies of Tunbridge Filmy-fern.

Species forming canopy Number of colonies

Rhododendron ponticum 14
Ilex aquifolium 12
Betula pendula 10
Taxus baccata
Pteridium aquilinum
Sorbus aucuparia
Fagus sylvatica
Castanea sativa
Dryopteris dilatata
Quercus robur
Corylus avellana
Larix decidua
Rubus fruticosus
Acer pseudoplatanus
Fraxinus excelsior
Picea abies

Pinus sylvestris

~

=H BRS Ke PON NH WW BBA O

The population age structure was investigated by measuring the size of each patch
(calculated as maximum length x width; gametophytes were not included). As the plants grow
vegetatively outwards, the age of the patches can be crudely estimated from the size of the patch
using the annual average radial growth rate of 0.833 cm per year in north Wales (Richards &
Evans 1972). This growth rate compares well with a rate of 0.75 cm per year for Philpots
calculated indirectly from the data in Paton (1956). It can be assumed that generally the larger
the patch, the older it is but this may not always be the case (Comyn 1953; Sheffield et al. 1993).
Once sporophytes establish, they grow outwards from the centre of a patch in all directions and
increase in diameter. Later the centre of the patch may die off leaving several small patches
around the edge, which may slowly recolonise the centre after the dead fronds fall off. Where
patches were observed to be the remains of larger patches they were excluded from the size/age
class analysis. The growth rate is also likely to vary depending on climate, canopy cover, etc.

TUNBRIDGE FILMY-FERN IN SE ENGLAND 39

20

Frequency 10

0 1000 2000 3000 4000 5000 6000 7000
patch size (cm?)

Fig. 4. Bar chart showing relationship between number and size of patches of Tunbridge
filmy-fern in south-east England in 1994/1995 (fragmented patches and the largest patch sized
20800 cm2 not included)

The frequency of the different patch size/age class is shown in Figure 4. The bar chart
shows two interesting features. First, there are fewer patches of the smallest size class than the
next class indicating that recruitment of young plants has been low during the last 15 years.
Second, there are few patches 1001-2000 cm2 (estimated age 21-30 years old), with a peak of
patches sized 2001-2500 cm2 (estimated age 30-34 years old).

DISCUSSION
Distribution in 1994/1995
The sandrocks in south-east England have been extensively searched by F. Rose, E. C. Wallace,
J. A. Comyn and many others, and it is unlikely that new sites remain to be discovered.
Individual sites are complex and difficult to search exhaustively, especially where the rocks are
covered with bracken, bramble, rhododendron or storm damaged trees, and though some sites
were visited six times in 1994/1995, some patches and/or colonies may not have been found.

Most sites are concentrated in the Ardingly and the Tunbridge Wells complexes of sandrocks
in the north of the Weald (see map in Robinson & Williams 1984), with single isolated
occurrences in Uckfield and Redleaf areas. It is assumed that these are relict sites from a wider
distribution earlier in this interglacial. Another relict, Killarney fern (Jrichomanes speciosum),
occurs in at least two sites with the Tunbridge filmy-fern as the gametophyte.

The analysis of the distribution data (Tables 1 and 2) show that the fern has declined in south
east England, but the long-term population cycles cannot be determined from only two surveys.
Our current thoughts are that the fern is declining and is under severe threat in all eight sites
with single colonies - six of these only have one patch present. The filmy-fern is also thought
to be declining nationally (Richards & Evans 1972), but was not found to have declined
significantly in Britain as a whole since the 1950s in the BSBI Monitoring Scheme 1987-1988
(Rich & Woodruff 1990). Our detailed data (Richardson, Rose & Rich 1995) will provide
precise information against which to test changes in the future.

Pentecost & Rose (1985) concluded that the main reasons for the decline of cryptogams on
the sandrock outcrops were spread of rhododendron and other trees and trampling, though for
lichens collecting and air pollution may also have played a part. Similarly for the filmy-fern a
variety of reasons may have caused the decline. The main reasons for loss or contributory
factors appear to be too much shade (especially dense rhododendron invasion in some areas and

60 FERN GAZETTE: VOLUME 15 PART 2 (1995)

shade from beech, holly and yew elsewhere), clearance of woodland (e.g. Rose 1952), and storm
damage. Historically, public pressure and collecting may also have caused decline (e.g. Bennett
1851). The 1987 storm removed much of the dense shade which could be regarded as partially
beneficial in the longer term provided that the woodlands are replanted with broad-leaved trees
which give light shade, and managed appropriately.

Habitat

The fern grows in moist, sheltered places which are usually shaded and rarely in direct sunlight,
but there 1s little quantitative data available on the microclimate which is likely to vary from the
ambient climate of the Weald. Comyn (1953) found no seasonal variation in relative humidity
in Philpots Wood.

Comyn (1953) observed the filmy-fern in a variety of habitats at Philpots Wood including
“moist rock faces, damp ledges and seepage lines, boulders near the stream, boulders on top of
the main rocks, low down on drier shaded boulders or high up on exposed rock faces” and found
it was “impossible to tie the plant down to any particular type of sandstone face or any particular
microclimate”. This is still generally true in 1994/1995, but plants are no longer present on
exposed, south-facing sites.

A. C. Jermy (pers. comm. 1994) has noted that after the canopy had been opened,
Hymenophyllum patches were often frosted and snow and ice pulled it off the rocks, though mats
lower down the rocks were often protected by fallen leaves. Hymenophyllum tunbrigense does
not seem sensitive to even quite severe cold (Richards & Evans 1972). It is likely to be sensitive
to drought.

Paton (1956) described the cyclical pattern of succession in the bryophyte communities in
the Weald (including Hymenophyllum), where colonisation was followed by a gradual build up
of a bryophyte mat which eventually fell off under its own weight leaving bare rock to start the
cycle again. During the field work, parts of Hymenophyllum patches were noted peeling off in
four sites for no apparent reason.

All the sites are probably ancient woodland, though some are replanted and some less than
2 ha are too small to be included in the inventories (Whitbread, Barton & Hutton 1984a, 1984b;
Pritchard et al 1994). The natural woodland type around the rocks is almost always W10
pedunculate oak - bracken - bramble woodland (Rodwell 1991). Many of the woodlands have
severe rhododendron invasion and this has suppressed or even eliminated the ground flora, and
some sites have been replanted with conifers. In the Wakehurst-Chiddinglye complex (sites 5-
9) beeches mark the line of the rocks in the woodland (A. Jackson, pers. comm. 1994), the
community type being close to the W14 beech - bramble woodland (Rodwell 1991).

The canopy appears most suitable when composed of deciduous trees (including larch), but
plants will grow in light shade from rhododendron, holly, yew and forestry conifers. Comyn
(1953) noted that patches died if they become more exposed by removal of bushes or felling of
trees, though sometimes small parts survived in the more sheltered and damp localities. Hence
woodland continuity, or at least continuity of a mosaic of suitable small patches of woodland, is
likely to be essential for the long-term survival of the plant, although it must have survived
previous losses of canopy caused by storms and woodland management. Conversely, Comyn
(1953) observed that when the filmy-fern is shaded by holly or rhododendron the plants cease
to be vigorous and die off, and Evans (1964) noted holly was a frequent associate and that
rhododendron was detrimental to the growth of the fern. The predominance of rhododendron in
the canopy, notorious for casting dense shade, is thus now a cause for concern.

Comyn (1953) listed the following associates of Hymenophyllum tunbrigense on the
sandrocks: Cephalozia lunulifolia (Dum.) Dum. (frequent), Cephalozia connivens (Dicks.)
Lindb. (frequent), Calypogeia integristipula Steph. (frequent), Odontoschisma denundatum
(Mart.) Dum. (fairly frequent), Lepidozia reptans (L.) Dum. (fairly frequent), Bazzania trilobata

TUNBRIDGE FILMY-FERN IN SE ENGLAND 61

(L.) S. F. Gray (occasional), Tetraphis pellucida Hedw. (frequent), Dicranella heteromalla
(Hedw.) Schimp. (frequent), Leucobryum glaucum (Hedw.) Angstr. (fairly frequent), Mnium
hornum Hedw. (fairly frequent), /sopterygium elegans (Brid.) Lindb. (frequent), /sothecium
myosuroides Brid. (occasional), Dryopteris sporelings, Lepraria incana (L.) Ach. (frequent),
Cladonia furcata (Huds.) Schrader (occasional) and other lichens. This is still broadly true
today (H. W. Matcham, pers. comm. 1994).

Regeneration

The discovery of gametophytes is pleasing as this has been only rarely reported before (e.g.
Rumsey, Farrar & Sheffield 1990). Their presence may be due to the very mild autumn in 1994
(the mildest November on record) suggesting that regeneration from spores may be an irregular,
climate-dependent event. Richards & Evans (1972) thought regeneration was mainly
vegetative, but there is little doubt that it reproduces both by vegetative spread and spores.
However, the small population sizes, often with one large patch only present, suggest that
establishment from spores may be an infrequent event. Comyn (1953) recorded that it only
colonised bare rock where it was moist, but may be able to colonise rocks covered with
bryophytes as part of the patch dynamics of the lower plant communities (Paton 1956).

The frequency of the different patch size/age class is interesting. We tentatively suggest
that the under-representation of the smallest size classes may be due to the storms of 1987 and
1990 which have resulted in loss of canopy cover which have caused mortality or affected the
establishment of new and young plants, especially in the drought summers of 1989-1992. The
low frequency of 1001-2000 cm2 size classes suggests that recruitment/mortality between the
early 1960s and early 1970s was markedly affected. Interestingly, Comyn (1953) noted that
many of the patches of filmy-fern in Philpots “looked extremely unhappy; often there is a larger
proportion of dead than living fronds”. Ten years later in 1963, Evans found nearly all the
colonies marked by Comyn (1953) had died (Richards & Evans 1972). This suggests some
catastrophic event which also coincides with the time at which Hymenophyllum disappeared
from three sites (Table 1), and clearly also declined at many others (Table 2). It is also possible
that recruitment is better in some years than others leading to the variation in size classes, but
this would not explain the loss of patches observed between 1953 and 1963.

We can offer no definitive explanation as to the cause of this widespread early decline. The
unhealthy patches at Philpots noted by Comyn could be due to dense shade due to the spreading
of rhododendron during this period, or perhaps severe air pollution. The loss of patches noted
by Evans may be due to the severe winter of 1962/1963: the cold periods during the winter were
separated by a brief thaw which resulted in water running over the rocks which froze again and
pulled off large sheets of bryophytes (and possibly the filmy-fern). The effects of the winter
were also observed by Evans (Richards & Evans 1972) who noted one third of the patches in
North Wales lost their leaves in the winter. What is clear is that all colonies have declined in
size since the early 1950s.

Conservation

All the remaining populations of the filmy-fern are very small; six sites have only a single patch,
and only one has more than four colonies. It is clear that the status of the fern is very precarious
and it is likely that there will be further loss of sites during the next few years unless
conservation management is carried out.

The best growth condition for the fern is medium shade. Historically the woodlands over
the rocks probably had a canopy composed of birch, rowan and oak, and ideally woodland
management should aim to replace a patchwork mosaic of this composition. Woodlands
damaged by the storm or shaded by too much rhododendron should therefore be replanted with
birch and oak to provide appropriate shade, and the rhododendron eliminated. This should be

62 FERN GAZETTE: VOLUME 15 PART 2 (1995)

carried out gradually rather than all at once to prevent catastrophic loss of canopy!

The possibility of restoring the fern to old sites where conditions are suitable should be
investigated, with regard to conservation of the genetic resource. Alternative techniques for
transplanting are being be investigated, as previous attempts have not been successful. The
possibility of restoring the fern from spore banks (Dyer 1994) is also currently being
investigated.

ACKNOWLEDGEMENTS
We would like to thank the Balcombe Estate, Lord Gibson, David Howard, Mr Preston, Mr
Simpson, and others for access to private land.

We would also like to thank Penny Angold, Mary Briggs, Rob Cooke, Pam Copson, Simon
Davey, Megan Dowlen, Adrian Dyer, Peter Hall, Paul Harmes, Nick Hinson, Clive Jermy,
Derek Hill, Andy Jackson, Serene Marner, Howard Matcham, Jane O’Dell, Alison Paul, Eric
Philp, Philip Richardson, Martin Rickard, Rod Stern and David Streeter who have provided
information or helped with the field work. |

We would especially like to thank Jean Paton (nee Comyn) for permission to quote from her
thesis and answering our queries and Clive Stace for details of the records he has collated over
the last 35 years. We would like to thank the Keepers of the herbarium at the Booth Museum
at Brighton, Kew, Liverpool Museum, Oxford University Herbarium, the Natural History
Museum, Tunbridge Wells Museum and Art Gallery, and Warwick Museum for help, and access
to the herbaria and libraries.

REFERENCES

ARNOLD, F. H. 1887. Flora of Sussex. Simpkin, Marshall, Hamilton, Kent & Co., London.

ARNOLD, F. H. 1907. Flora of Sussex. 2nd edition. Simpkin, Marshall, Hamilton, Kent &
Co., London.

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64 FERN GAZ. 15(2)1995

ANTHERIDIOGEN SYSTEM IN THE FERN ASPLENIUM RUTA-
MURARIA
(ASPLENIACEAE: PTERIDOPHYTA)

J.J. SCHNELLER & ANNATINA HESS
Institute of Systematic Botany, Zollikerstrasse 107, CH-8008 Ziirich, Switzerland

Key words: Asplenium ruta-muraria, sex determination, antheridiogen, breeding system.

ABSTRACT

Recent experiments with Asplenium ruta-muraria have shown that adding old prothalli or
parts of previously used medium (on which prothalli had matured) to a culture with freshly
sown spores results in a precocious formation of antheridia, indicating that an antheridiogen
system exists in Asplenium. However, application of GA3 to young cultures of A. ruta-
muraria does not result in precocious formation of antheridia, unlike the situation in some
other genera. The presumed occurrence of an antheridiogen system in this tetraploid
inbreeding species cannot convincingly be interpreted as a means for promoting outbreeding.
It may either represent a remnant of an outbreeding ancestor or it is correlated with
constraints given by the fertilization itself depending on the number of spermatozoids.

INTRODUCTION

Although only a relatively small number of genera and species have been tested (Haufler 1987,
Soltis & Soltis 1987, Raghavan 1989), it seems likely that antheridiogen systems are a common
phenomenon in many homosporous (leptosporangiate) ferns. However, as shown in a review by
Naf (1979) antheridiogens do not occur in all the investigated species. Following Schedelbauer
(1974), Naf (1979), and Haufler & Ranker (1985) three main types of antheridiogens can be
distinguished: Ap, in Pteridium aquilinum and Dryopteris filix-mas (many species and genera
seem to be sensitive to that antheridiogen), Ay, in Anemia and Lygodium and Ac, in
Ceratopteris. A,, 1S chemically related to gibberellic acid (GA3). In schizaeaceous ferns like
Anemia and Lygodium, replacing the antheridiogen by GA; had the same effect (Schraudolf
1962). Whereas the chemical structure of A,,, has been revealed (Naf et al. 1975, Yamane et al.
1987), we still do not know much about the structure of the other antheridiogens. As for
gibberellic acid, very low concentrations of antheridiogen are sufficient to induce the specific
effect.

It seems to be too early (except perhaps for A,,,) to look for a relationship between type of
antheridiogen and taxonomic group.

Previously, for Asplenium it has been found that neither A. trichomanes nor A. ceterach
(Ceterach officinarum) reacts to Ap, (Dépp 1959). Based on earlier observations that in mixed
cultures of Asplenium ruta-muraria small male gametophytes and taller hermaphrodites occur,
we examined whether an antheridiogen system is responsible for precocious antheridia
formation and for the occurrence of male-only gametophytes.

MATERIALS AND METHODS
Spores
Spores were harvested from one plant grown on a man-made wall near the Botanic Garden of
Ziirich, Switzerland. Leaves with mature sporangia were briefly rinsed with water, then dabbed
with tissue-paper, placed between two sheets of paper and dried. The spores were stored for
approximately one month under these conditions until sowing.

ANTHERIDIOGEN SYSTEM IN A. RUTA-MURARIA 65

Cleaning (washing) and sterilization of spores

Spores were collected by tapping the sheets of paper (on which the fertile leaves have been
dried) carefully over an eppendorf tube (one leaf per tube was used). Two ml distilled water and
1 to 3 drops of detergent (for example “Handy’-wash up soap) were added to the spores. The
whole mixture was shaken, centrifuged for 10 to 15 seconds at 6000 r.p.m. and the liquid
Supernatant was removed. Two ml distilled water were added to wash the spores and the process
was repeated. In some cultures spores were used that had been washed only with distilled water.
For the other cultures spores were first sterilized as follows. The liquid was removed after
centrifugation and the precipitate (spores) was mixed with | ml of a 5%-sodium hypochlorite
solution, centrifuged and the supernatant removed immediately. It was important that the
sterilization procedure should last not more than 40 seconds (Seifert 1992). Then the surface
sterilized spores were rinsed three times as above with distilled water and then the spores were
soaked in 6 ml of sterile water. From this solution of spores we used 0.5 ml per sowing which
was spread on the culture medium in petri dishes.

Culture medium
Most of the sowings were made on agar medium containing a nutrient solution according to
Mohr (1956). The pH was adjusted with KOH to 5.2.

For the cultures on soil a mixture of quartz sand and garden-mould (based on compost with
40% peat) in a ratio of 1:1 was used. This mixture was put in the microwave oven in a covered
bowl and heated for five minutes at maximum power. It was uncovered afterwards and cooled
down. This procedure was repeated once. The pH of this medium was 5.5. For the cultures small
petri dishes with a diameter of 5 cm and a height of 1.5 cm were used.

After sowing, the vessels were closed with parafilm-strip. The cultures were stored in
continuous light at 22°C.

In some experiments, agar pieces (about 4mm?) were removed from one vessel with a sterile
knife and placed on the medium in the new dish.

In other experiments gibberellic acid (GA3; Fluka Chemie AG, Buchs, Switzerland) was
applied at a concentration of 10° g per liter. The solution was sterilized through a filter
(0.2mm), then 0.3 ml were added to the petri dishes.

Experiments performed

Experiment I was designed to test the influence of spore treatment on germination and growth
on the two media. In addition, we used the cultures to study when antheridia and archegonia
develop and to find out if an interaction between well and less developed prothalli exists. The
spores sown on agar had either been treated with a 5%-hypochlorite solution or washed only in
sterile water. About every two weeks the dishes were opened to add some distilled water. The
spores sown on soil were treated with water only.

Experiment IJ: When prothalli in Experiment I reached a stage of about 100 to 200 cells (1
month old), 30 prothalli were isolated (one per dish) in the sterile-bench under a microscope,
using an injection needle. These cultures were used to monitor sexual differentiation of the
gametophytes.

Experiment III: To four 9 day old cultures four mature, hermaphrodite (1.5 month old)
gametophytes each were added. The sexual differentiation of these older gametophytes and the
reaction of the younger ones was monitored.

Experiment IV: We added agar pieces (about 4 mm? ) from older cultures, whose gametophytes
contained archegonia and antheridia, to four 9 days old cultures and asked whether these agar
pieces could cause a hastened antheridia differentiation on the young cultures. If such a reaction
was observed, we determined whether there existed a correlation between the distance to the

66 FERN GAZETTE: VOLUME 15 PART 2 (1995)

piece of agar and the occurrence of antheridia.

Experiment V: To four cultures that were about three weeks old, 0.3 ml of the gibberellic acid
(10> g/l) was added and subsequent differentiation and development was monitored.
Controls: No mature gametophytes were added to the 9 days old cultures at the beginning of
Experiment III. In Experiment IV young cultures (of the same age as in Experiment III) were
grown without adding agar pieces from older cultures. In the control for Experiment V no
gibberellic acid was added to cultures.

RESULTS
The influence on germination of the different treatments of the spores are seen in Figure 1. The
spores sterilized in hypochlorite, in comparison with those treated only with water, germinated
somewhat later and after 40 days developed on average smaller prothalli. However, the
difference was not striking and it appears that the sterilization had only a slight effect on the
vitality of the spores compared to those treated with water only. Older cultures of different
treatments contained gametophytes that were equivalent in size and sexual maturity.

200

A spores washed in water

OQ spores washed in Hypochlorite

160

120

80

number of cells

40

6) 5 TO 15° 7,20 Zo 30° 35 340
age of the prothalli (days)

Figure 1: Number of cells of prothalli in relation to the age under different treatments of the
spores (each point represents the mean of 50 examined prothall1)

In Experiment I the first sexually mature prothalli were hermaphrodites developing
archegonia and antheridia simultaneously. Subsequently male-only gametophytes were
observed. At that stage the number of antheridia per gametophyte was much higher than that of
archegonia. There were slightly more than 30 antheridia per prothallus but very few archegonia.
One could observe “late-comers” (gametophytes from later germinated spores) that consisted of
fewer than 10 cells yet contained antheridia.

Because observations on soil cultures were more difficult and time consuming than those on
agar cultures they were carried out less frequently. To evaluate the sexual status the prothalli had

ANTHERIDIOGEN SYSTEM IN A. RUTA-MURARIA 67

to be cleaned of soil and prepared on a slide for microscopical observation. It was very difficult
not to damage the gametophytes while cleaning them. The pattern of development of these soil
cultures did not differ from that of agar cultures.

The isolation of the small, delicate gametophytes (100 to 200 cells) in Experiment II was
quite difficult. For this reason some prothalli (ca. 10%) did not survive the treatment. The
isolated prothalli developed exclusively into hermaphrodites. The first appearance of antheridia
could be seen at almost the same stage as in the multi-gametophyte cultures. The slight
retardation observed could be related to isolation.

In Experiment III two to three days after the translocation of older prothalli with archegonia
and antheridia the young gametophytes started to produce antheridia but no archegonia formed.
After ten days the young resident prothalli of about 20 cells in size contained a large number of
antheridia but no archegonia, whereas those with 40 to 50 cells often remained vegetative at the
same date. All the translocated gametophytes developed into hermaphrodites.

In most of the cultures of Experiment IV it took about seven to eight days after the
application of agar pieces (from a well-developed culture) before the resident gametophytes
showed a reaction. Prothalli containing 20 to 25 cells produced antheridia but never archegonia.
The male prothalli could only be found in close proximity to the edges of the transferred media
pieces. Early antheridial formation could not be observed in all dishes of this experiment. In the
cases where no reaction was found it is likely that the piece of agar contained too small an
amount of an antheridia-inducing substance.

In Experiment V about three weeks after spore sowing, when the plants had a maximum size
of 10 to 20 cells, gibberellic acid was added. Some of the cultures showed a strange, stocky
growth. The prothalli stayed small and the cells were globular (Fig. 2). However, even 20 days
after GA3 application no sexual organs could be seen.

mae

50 pm

b

Figure 2: a) Stocky grown prothallus from experiment 5 after GA; addition. b) normally
grown prothallus.

DISCUSSION

The aim of this work was to examine whether an antheridiogen system exists in Asplenium ruta-
muraria that controls antheridial formation. Several observations support this hypothesis (Fig.
3). Isolated prothalli always developed into hermaphrodites, the first prothalli in a dense culture
produced gametangia of both sexes, but later smaller males developed. We interpret the
hermaphrodites as antheridiogen producers that induced the smaller prothalli around them to
become male only.

The outcome of Experiment IV can be explained by assuming that the sexually mature
prothalli secrete an antheridiogen into the medium. One week after the cut agar pieces (from a

68 FERN GAZETTE: VOLUME 15 PART 2 (1995)

well developed culture) were applied to young cultures, antheridia developed on prothalli close
to the agar piece. This could be explained either by low antheridiogen concentration in the agar
piece or by slow and slight diffusion of antheridiogen from the transferred media pieces into the
adjacent substrate. If antheridia could be found in a culture dish, there was always a subsequent
accumulation of them. It seems that a certain threshold has to be reached in the medium before
antheridial formation is induced.

When the appearance of antheridia under the different growth conditions is compared it can
clearly be seen that isolated prothalli and prothalli in dense cultures formed antheridia at a much
later stage of development than did young prothalli in the presence of older prothalli and after
medium application from older cultures. This can be explained when assuming the presence of
an antheridiogen system in A. ruta-muraria, which means that sexually mature gametophytes
are capable of producing a soluble substance (antheridiogen) which diffuses into the
surrounding medium and induces antheridial formation.

One other possible explanation cannot be excluded. Growth inhibitors may be formed by
older prothalli and antheridial formation may result from conditions of growth. In this case the
occurrence of males or precocious antheridial formation may be due to an indirect influence.
However, the fact that isolated prothalli or the larger ones within a mixed culture develop into
hermaphrodites may indicate that antheridial formation is not correlated with growth inhibition.

Gibberellic acid (GA3) did not induce early antheridial formation, and it can be inferred that
the Asplenium antheridiogen is not of the type Ay, which can be replaced by GA; (Schraudolf
1962). It has not been established whether the presumed antheridiogen of A. ruta-muraria is
similar to Ap, or Ac, or whether it represents a new antheridiogen class. It would be interesting
to do cross species experiments to establish this.

70

60

50

40

30

20

10

number of days till the first antheridia appeared

4 isolated >100 proth/ 1 isolated sowings with sowings with

proth ./dish dish proth./dish older proth. substrateapplication

(Experiment 3) (Experiment 1) (Experiment 2) in it from older proth.
(Experiment 3) (Experiment 4)

Figure 3: Antheridial formation dependent on the age.

ANTHERIDIOGEN SYSTEM IN A. RUTA-MURARIA 69

The different sets of cultures showed clearly that the age and size of the prothalli influenced
the velocity of reaction. Prothalli of about 20 cells (9 days old) reacted very quickly, while it
took the older ones (consisting of 100 or more cells) longer to differentiate antheridia. Some of
the older prothalli remained sterile. These results suggest that sensitivity to the presumed
antheridiogen decreases with the age of the prothalli. Such a phenomenon has been discovered
in other ferns (Naf 1979). For example the prothalli of Lygodium japonicum are most sensitive
to antheridiogen at an age of about 12 days. After 14 days the sensitivity decreased by 50%
(Naf, 1960).

There was no clear difference between the time of first appearance of antheridia in dense
cultures and that for isolated prothalli (Fig. 3). In the dense cultures the initiation of antheridia
tended to be at an earlier stage than in the isolated prothalli, but this slight retardation could also
be an effect of the isolation. The concentration of antheridiogen is assumed to be smaller in
isolated cultures and the threshold of antheridia initiation may be reached later than in mixed
cultures.

In summary, Asplenium ruta-muraria has a system that controls antheridial differentiation
and induces precocious antheridia in young prothalli. This can be explained by assuming the
existence of an antheridiogen, the first record of the occurrence of an antheridiogen system in
the genus Asplenium. However, the formation of growth inhibitors as an indirect factor inducing
antheridia cannot be completely excluded as an alternative explanation of the observations.

It is assumed that antheridiogens are a means for promoting outbreeding (Schneller et al.
1990). However, Willson (1983) writes that “there is no reason to believe that this is the sole
function”. For example, retarding the development of neighbours (males) might increase the
availability of resources for the female. In this view antheridiogen production is a means for
allelopathy.

The assumed presence of an antheridiogen system in Asplenium ruta-muraria raises some
interesting inconsistencies. This species is capable of successful intragametophytic selfing and
inbreeding (Suter & Schneller 1986). Populations on recently constructed walls (about 20-40
years old) seem to consist mainly of one single genotype per location (Schneller 1991), the
result of one single founder spore and gametophyte respectively. Thus in these populations the
antheridiogen system in this species cannot be interpreted as a means for promoting outbreeding
in the sense of mixing gametes of different genotypes. It may represent a remnant of an
outbreeding ancestor (an inherited trait) and may not be of adaptive value any more. Haufler &
Gastony (1978) suggested that the occurrence of an antheridiogen system in the obligately
apogamous Bommeria pedata is due to the fact that a loss of the antheridiogen system has not
yet become established.

On the other hand, the development of an antheridiogen system may be correlated rather
with constraints given by the type of fertilization found in ferns (dependent on free water) than
with the promotion of outbreeding. The production of spermatozoids could be a “bottleneck”
and fertilization is warranted only when a certain number of spermatozoids is produced. The
production of sufficient antheridia (spermatozoids) on one hermaphrodite prothallus may limit
the subsequent development of the embryo because antheridial formation may need resources
otherwise allocated to the young sporophyte. Therefore, it could be advantageous for an
archegonium-bearing prothallus to induce antheridia (spermatozoid) formation on neighbouring
individuals and one could speak of “division of labour”.

ACKNOWLEDGEMENTS
We thank Dr. M. Gibby and J. Vogel for their linguistic corrections and critical reading. We
thank especially Chris Haufler and an anonymous referee for very valuable comments and
suggestions which much improved the content of the manuscript.

70 FERN GAZETTE: VOLUME 15 PART 2 (1995)

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FERN GAZ. 15(2)1995 71

A NEW SPECIES OF HUPERZIA (LYCOPODIACEAE:
PTERIDOPHYTA) FROM INDIA

PAPIA MONDAL and R.K. GHOSH
Cryptogamic Unit, Central National Herbarium, Botanical Survey of India,
Howrah-711103, West Bengal, India.

Key words: Huperzia dixitiana, Sikkim, India.

ABSTRACT

Huperzia dixitiana Mondal & Ghosh is described and illustrated as a new species from
Sikkim, closely related to and previously reported as H. selago. Details of its distribution
and relationship to H. selago are outlined.

INTRODUCTION

While identifying pteridophytes collected from Sikkim, the authors came across a few
specimens of a Huperzia Bernh. which could not be matched with any of the specimens housed
in the Calcutta Herbarium either from India or abroad. Some of these specimens had previously
been cited under H. selago by Chowdhury (1937), Mehra and Bir (1964) and Dixit (1988), but
appeared quite distinct from that taxon. In view of the floristic continuity of the Indo Himalaya
fern flora with that of China and Tibet, a specimen collected by one of us together with a
detailed description was sent to the Keeper of the pteridophyte herbarium, Institute of Botany,
Academia Sinica, Beijing (PE) for confirmation of our opinion that it might represent a new
taxon. The keeper could not identify the specimen as belonging to any of the species housed in
PE with certainty but doubtfully suggested that it might be “Lycopodium selago L. var
appressum (Desv.) Ching.” Further study by us of literature and of specimens of Huperzia
appressa (Desv.) A. & D. Love [=Lycopodium selago var. appressum (Desv.) Ching] revealed
that this taxon differs from our material in having entire leaves and in some other features of
growth habit etc. and is confined to the Arctic zones of America, Europe and Asia as a
circumpolar element (see Ching 1981, Hylander 1953 and Love & Léve 1961). Although Léve
and Léve (1961) appeared to treat it as both a species and a subspecies, later authorities (eg.
Ching 1981, Kukkonen 1984) have treated it as merely a variety of H. selago and it is one of
several different relatively minor taxa usually treated today as being of infraspecific rank within
that species. It is now more correctly known as H. selago subsp. arctica (Grossh. ex Tolm.) A.
& D. Léve (see Tutin (ed): Flora Europaea 1993 and Jonsell (ed) Flora Nordica 1995, the latter
pointing out that intermediates also exist between it and subsp. selago).

Huperzia selago is evidently a polymorphic species which has diverged into a number of
different forms in different parts of its range, some perhaps mainly reflecting phenotypic
plasticity due to the environment, others perhaps mere ecotypes and others representing
geographical races treated as being of definite taxonomical significance. Thus in Europe subsp.
arctica seems likely to be a dwarf, compressed Arctic ecotype of somewhat uncertain stability,
closely related to the more widespread subsp. selago, both having untoothed leaves, while
subsp. dentata (Herter) Valentine (= H. dentata (Herter) J. Holub), which is taller, more robust
and has markedly long-serrate leaves, is a more separate and discrete entity confined to the
Azores. It is usually as a good species in its own right. Fraser-Jenkins (pers. comm. 1994) has
given us details of H. selago’s occurrence in Asia and of material housed at BM, K and E. Thus
in Asia subsp. arctica occurs widely across the more northerly latitudes from west to east Siberia
and in north China, Mongolia and Japan, extending locally southwards in the former Soviet
Central Asian mountains and in central-west China. Further south in the C.I.S. (former
U.S.S.R.) it is replaced by subsp. selago which extends southwards in Turkestan and the Pamirs

72 FERN GAZETTE: VOLUME 15 PART 2 (1995)

and across to Pakistan and Kashmir (Chowdhury 1937, Stewart 1945 etc., Fraser-Jenkins 1992
and Khullar 1994) and see map in Hultén (1964) and is also very scattered and rare along the
Himalayan main range as far as central Nepal (Gurung 1976 and Fraser-Jenkins, pers. comm.
1994). It also extends southwards in central-west China and is present in Japan. The south of
its range in south-west China and Tibet is directly relevant to our collection because following
receipt of the present paper Fraser-Jenkins (pers. comm. 1994) has stated that subsp. selago
becomes replaced there by a closely related taxon with wavy to serrulate distal margins of the
leaves which occur in Szechuan (Sichuan), Yunnan and southernmost Tibet. This taxon is also
a small plant with narrow stems and, though we have not ourselves examined Chinese or
Tibetan material it is evidently close to the material from Sikkim we refer to and according to
Fraser-Jenkins (pers. comm. 1994) may be the same as the taxon referred to in Flora Xizangica
(1983) as H. tibetica (Ching) Ching, while another specimen referred to, which again we have
not had the opportunity to study, H. /ajouensis Ching, appears very similar but smaller, though
the leaf-margin is not described.

In our opinion the consistently small size and distinctive tendency for our present material
to develop distal wavyness or serrulations in the leaves is sufficient to justify treating it as a
species distinct from H. selago, which we therefore describe below. Fraser-Jenkins (pers.
comm. 1994) has subsequently pointed out that material of it at BM has been identified by Dostl
in 1964 as “H. selago var. himalaica, nom. prov.” a taxon he has not published. The new species
is as follows:-

HUPERZIA DIXITIANA P. Mondal et R.K. Ghosh, spec. nov.

H. selago sensu Chowdhury (1937) p.p., Mehra and Bir (1965) and Dixit (1984) and in
Lycopodiaceae in India: 42 t. I, f. 1 a-b (1988), material from Sikkim, excluding description and
figure.

Species nova, plantis minutis, 1.5-3cm altis, foliis confertis, adscendentibus, in siccis pallide
viridibus, 4-5 x 0.9-1 mm, membranaceis ad margines sinuatis vel serrulatis, sporophyllis quam
folias vegetativas angustioribus, sporis brunneis magne foveolatis a congeneribus diversa.
HOLOTYPUS: N. Sikkim, Lachen Valley, Youngtham. R.K. Ghosh & B. Ghosh 66439,
26.5.1989 (CAL).

ISOTYPES: Ibid. R.K. Ghosh & B. Ghosh 66439 (PE, K. CAL).

Figure 1. Huperzia dixitiana Mondal et Ghosh 66439(Cal). a. Holotype b. Isotype

HUPERZIA DIXITIANA FROM INDIA G3

Other specimens examined: Sikkim s. loc, s. coll., s.n. (CAL accession no. 29154); Nakuchum,
5000m. W.W. Smith & G.H. Cave 1962, 4.8.1909 (CAL); Eumtso Lo, 5000m. W.W. Smith &
G.H. Cave s.n. 12.7.1909 (CAL); both specimens cited by Mehra & Bir (1984), Chowdhury
(1937) and Dixit (1988) sub H. selago. Specimens seen and identified by Fraser-Jenkins (pers
comm. 1994): E. Sikkim, Kupup, Memyochu., P.K. Hajra 337, 26(5) 1980 (BSHC), up to 5cms
tall; N. Sikkim, near Lunak La to Jheel, Muguthang, “up to 10 cm”. S.K. Rai 9465, 5.8.1988
(BSHC); C. Nepal, Chilime Kharka, 13000 ft. O. Polunin 1436, 7.1949, up to 2cms tall; E.
Nepal, Lamo Pokhari (2900m) to Gupha Pokhari (2800m), along path in open place.

H. Kanai, H. Ohashi, K. Iwatsuki, H. Ohba, Z Iwatsuki & P.R. Shakya 725178, 10.6.1972
(KATH), up to 2.5cms tall; S.E. Tibet, Tsari District, Chikhar, 28° 42’, 93° 18’, 13500ft.

F. Ludlow, G. Sherriff & G. Taylor 6370, 16.10.1938 (BM), up to | inches tall; S.E. Tibet,
Kongbo Province, Lusha Chu, 29° 27’, 94° 35’, 13000 ft. F. Ludlow, G. Sherriff & G. Taylor
4775, 11.6.1938 (BM), up to 2cms tall; N. Burma, Burma-Tibet border, sources of the Irrawady,
_Adung Valley, meadow, 28° 20’, 97° 40’, 12000 ft. F. Kingdon-Ward 9987, 30.8.1931 (BM) up
to 3.75cms tall (9987 includes some + untoothed specimens also accepted by Dostdl as
belonging to his “var. himalaica’’).

Plants 1.5 cm to 3 cm high, main stem 3-5 mm wide, erect to, more usually, slightly
decumbent at the base, once or twice dichotomously branched, rarely simple; a tuft of thick,
long roots present at the base. Leaves densely crowded, ascending, pale green or drying;
vegetative leaves larger than the sporophylls, narrowly lanceolate, 2-4 x 1-1.5 mm, margins
smooth in the basal half of the leaf, becoming distantly and irregularly wavy to serrulate towards
their apices, membranaceous in texture, midrib distinct up to 3/4 of the length of the leaf from
the base, leaf-apices acute. Sporophylls borne in the apical part of the stem, similar to the
vegetative leaves but smaller in size and more condensed, midrib distinct, margins similarly
irregularly wavy to serrulate towards their apices, leaf-apices acute. Spores brown, globose-
tetrahedra with sub-traingular faces, trilete, exine foveolate.

Ecology: Plants growing among short grass and moss on the ground in moist, open, sunny
Situations in high-altitude meadows etc. from c.3000-5000m altitude. Occurs in the higher
middle regions of the Himalaya main ranges above the tree-line and apparently extends into the
region behind the Himalaya in Tibet.

Distribution: Central and east Nepal; India: North Sikkim; south-east Tibet; north Burma.
Etymology: The species is named in honour of Dr R.D. Dixit, Scientist-in-charge of the
Cryptogamic Unit, Botanical Survey of India and Joint-Director of the Botanical Survey of
India, who has devoted his life to the study of the taxonomy of Indian pteridophytes and has also
revised the families Lycopodiaceae and Selaginellaceae on an Indian basis.

ACKNOWLEDGEMENTS

Grateful thanks are due to Dr P.K. Hara, Director of the Botanical Survey of India, for
encouragement We are indebted to Dr R.D. Dixit, for guidance, correspondence with China and
Britain and giving helpful suggestions concerning the typescript. Our thanks are also due to Dr
X.C. Zhang, Keeper of the Pteridophyte Section, Institute of Botany, Academia Sinica, Beijing,
for examining our specimen and giving his opinion and to Mr C.R. Fraser-Jenkins, c/o The
Natural History Museum, London, for critically examining our specimen and constructive
suggestions, also for providing informtion about other herbarium material not from CAL and
about the presence and taxonomy of H. selago in Europe and Kashmir, Nepal etc. and
throughout Asia as well as for giving literature references and critically revising the typescript.

74 FERN GAZETTE: VOLUME 15 PART 2 (1995)

Figure 2. Huperzia
dixitiana, isotype R.K.
Ghosh and B. Ghosh
66439(Cal). a. Proximal
surface of spore (scale b
= 50um). b. Apical
portions of sporophylls

REFERENCES

CHOWDHURY, N.P. 1937. Notes on some indian species of Lycopodium with remarks on the
distribution of the genus in India. Trans. Nat. Inst. Sci. India 1: 187-226.

DIXIT, R.D. 1984. A Census of Indian Pteridophytes: 8. Flora of India Series 1V. Howrah.

DIXIT, R.D. 1988. Lycopodiaceae of India: 42-44. Dehra Dun.

FRASER-JENKINS, C.R. 1992. The ferns and allies of the far west Himalaya. Pakistan
Systematics 5(1-2): 85-120.

TUTIN, T.G. et al. (eds.) 1993, Flora Europaea (ed. 2) 1. (Psilotaceae-Platanaceae): 3.
Cambridge.

JONSELL, B. et al. (eds.) 1995 (in press), Flora Nordica 1. Stockholm.

CHING, R.-C. & WU, S.-K 1983: Pteridophyta. In: WU, C.-Y. (ed.) Flora Xizangica |: 6-9,
Beiying.

GURUNG, V.L. 1976. Pteridophyta. In: MALLA, S.B. et al. (eds.), Catalogue of Nepalese
Vascular plants. Bull. Dept. Med. Plants 7: 1-27, Katmandu.

HULTEN, E. 1964. The circumpolar plants. I. Vascular cryptogams, conifers, monocotyledons.
Kungl. Srenska Vetenskapsal Handl., ser. 4: 8(5): 1-28.

HYLANDER, N. 1953. Nordisk Karlv xt flora 1. Stockholm.

KHULLAR, S.P. with Fraser-Jenkins, C.R. 1994. Pterdophytes of the West Himalaya 1. Dehra
Dun.

KUKKONEN, I. 1984. Diphasiastram. In: HMET-AHTI, L. & KUKKONEN, L.,
Nomenclatural combinations of Finnish vascular plants. Ann. Bot. Fennica, 21: 209-211.

LOVE, A. and LOVE, D. 1961. Some Nomenclatural Changes in the European Flora.
Botaniska Notiser 114: 33-47.

MEHRA, P.N. and BIR, S.S. 1964. Pteridophytic Flora of Darjeeling and Sikkim Himalayas,
Res. Bull. Panjab. Univ. 15(1-2): 101.

STEWART, R.R. 1945. The ferns of Kashmir. Bull. Torrey Bot. Club 72(4): 426.

FERN GAZ. 15(2)1995 ID

THE PANTROPICAL EPIPHYTE OPHIOGLOSSUM PALMATUM
(OPHIOGLOSSACEAE:PTERIDOPHYTA),
A NEW RECORD FOR BOLIVIA

PE. IBISCH. G: RAUER. D: RUDOLPH
Botanisches Institut der Universitat Bonn, Meckenheimer Allee 170, D-53115
Bonn, Germany.

The conspicuous and morphologically rather untypical member of Ophioglossaceae
Ophioglossum palmatum - the only species of the subgenus Cheiroglossa (Presl) Clausen - is
characterised by its deeply and irregularly lobed, palmate sterile lamina and its erect fertile
segments at the base of it. The variable species (GOmez, 1976) is one of the most widely spread
vascular epiphytes of the world: in the Paleotropics it is quite rare and has been reported from
Madagascar, Réunion, Zaire, the Seychelles and Vietnam (Mesler, 1974, 1975; Tryon & Tryon,
1982). In America it has been known more regularly from Florida, the West Indies and southern
Mexico to Peru, Guyana, and Brazil (Stolze, 1976; Tryon & Stolze, 1989). The two epiphytic
species of Ophioglossum (O. palmatum, O. pendulum) seem to be very rare and are
underrepresented in herbarium collections (Wagner, 1990).

Up to now O. palmatum has been overlooked in Bolivia, the botanically least investigated
country of South America (Solomon, 1989). It is neither cited in the only checklist of the
Bolivian flora (Foster, 1958), nor have any specimens been deposited in the national herbarium
of Bolivia (LPB). In none of the recent publications describing the distribution of this species
its occurrence in Bolivia is mentioned. Now, one individual has been found during an intensive
inventory of the epiphyte flora of a montane rainforest of North-Eastern slopes of the Andes
within the newly created national park Carrasco (Ibisch, in prep.): D. Rudolph, G. Rauer, P.
Ibisch 36 (LPB, herb. Ibisch), Sehuencas, Prov. Carrasco, Dep. Cochabamba, 65°17’W, 17°30°S,
approx. 2.100 metres above sea level. S angle oa ItFf Cus

In Florida O. palmatum grows in forests of Acer, Quercus, Taxodium and Sabal (Mesler,
1975). Only Sabal palmetto is colonized by this obligate epiphyte. This case sometimes is cited
as example for phorophyte specifity of epiphytes (e.g. Benzing, 1990). However, this is no more
than a ‘regional phorophyte specifity’. Probably, in the subtropical seasonal forests the fact that
roots and stems of the fern are covered by the leaf-base mantle of the palm (Mesler, 1975) is of
importance. The gametophytes can only establish where considerable moisture between leaf-
base mantle and stem of Sabal is provided (Mesler, 1975). In Peru O. palmatum is found on trees
and branches in cloud forests, elfin forests, and shaded ravines between 1.000 and 2.450 m
above sea level (Tryon & Stolze, 1989). However, it also occurs in the lowland rain forests of
Brazilian Amazon (Tryon & Conant, 1975). In Bolivia it has been found on Nectandra cf. laurel
(lower stem region) within primary montane rain forest (precipitation about 3-4.000 mm) which
is composed of species of Myrtaceae, Lauraceae, Hedyosmum, Weinmannia, Podocarpus and
many other tree taxa. The forest is rich in angiosperm (about 180 spp.) and fern epiphytes (about
35 spp.). Accompanying epiphytic pteridophyte species belong to the genera Asplenium,
Blechnum, Campyloneurum, Elaphoglossum, Grammitis, Huperzia, Hymenophyllum,
Microgramma, Niphidium, Pecluma, Polypodium, Pteris, Trichomanes, Vittaria, Zygophlebia
(Ibisch, in prep.). Obviously, in Bolivia O. palmatum is very rare - a good example of the wide
and scattered distribution of many epiphytes. The new site is the southernmost record in the
Andes and QO. palmatum is very unlikely to be found much more south where the seasonal
Tucumano-Bolivian forest (south of 18°S) begins which, in comparison, is quite epiphyte poor.
The statement of Solomon (1989) that the epiphyte flora of Bolivia is “much less species rich
than in comparable areas in Peru or Ecuador” partially is caused by the low collection density
in this country. O. palmatum is one example of many epiphyte taxa which have not been known

716 FERN GAZETTE: VOLUME 15 PART 2 (1995)

from the southernmost appendix of tropical Andean rain forest but which turn out to be more
wide-spread than expected and to reach the still neglected forests of Bolivia.

ACKNOWLEDGEMENTS
We thank Prof. Dr. W. Barthlott, Bonn, Dr. W. Lobin, Bonn, and Dr. J. Nieder, Bonn, for revising
this paper and helpful comments.

REFERENCES

BENZING, D.H. 1990. Vascular epiphytes. General biology and related biota. Cambridge
University Press, Cambridge.

GOMEZ, L.D. 1976. Variation in Costa Rican Ophioglossum palmatum and nomenclature of
the species. Amer. Fern J. 66: 89-92.

MESLER, M.R. 1974. The natural history of Ophioglossum palmatum in South Florida. Amer.
Fern J. 64: 33-40.

MESLER, M.R. 1975. The gametophytes of Ophioglossum palmatum, L. Amer. J. Bot. 62:
982-992.

SOLOMON, J.C. 1989: L. Bolivia. In: CAMPBELL, D.G., & HAMMOND, H.D. (eds.):
Floristic inventory of tropical countries. The New York Botanical Garden, New York.

STOLZE, R.G. Ferns and fern allies of Guatemala. Part I: Ophioglossaceae through
Cyatheaceae. Fieldiana Botany 39: 1-130.

TRYON, RM. & CONANT, D.S. 1975. The ferns of Brazilian Amazonia. Acta Amazonica 5:
23-34.

TRYON, R.M. & STOLZE, R.G. 1989 a. Pteridophyta of Peru. Part I. 1. Ophioglossaceae-
12 Cyatheaceae. Fieldiana Bot. New Ser. 20: 1-145.

TRYON, R.M. & TRYON, A.F. 1982. Ferns and allied plants with special reference to
tropical America. Springer Verlag. New York, Heidelberg, Berlin.

WAGNER, W.H. 1990. Ophioglossaceae. In: Kramer, K.U. & Green, PS. (eds.):
Pteridophytes and gymnosperms (Kubitzki, K. (ed.): The families and genera of
vascular plants, Vol. 1). Springer Verlag. Berlin, Heidelberg, New York.

THE BOTANICAL RESEARCH FUND
The Botanical Research Fund is a small trust fund which annually, in May, makes modest grants
to individuals to support botanical investigations of all types and, more generally, to assist their
advancement in the botanical field. It is available to amateurs, professionals and students who
are unable to obtain support from other sources. Where appropriate, grants may be awarded to
applicants in successive years to a maximum of three.
Applications should be made in writing (there are no forms) to the Hon. Sec:-
Professor Keith Jones, 57 Marksbury Ave., Richmond, Surrey TW9 4JE

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The British Pteridologi NAT l NAL
THE FERN GAZETTE :

VOLUME 15 PART 2 1995

CONTENTS

Page

MAIN ARTICLES

Studies on Intraspecific Variation in South Indian Ferns: Rediscovery of the
rare Diploid Cytotype of Christella parasitica (Thelypteridaceae Pteridophyta)

— V. Irudayaraj, S. Dominic Rajkumar and V.S. Manickam | 41

Tunbridge Filmy-Fern Hymenophyllum tunbrigense (Hymenophyllaceae
Pteridophyta) in South East England in 1994/1995

— T.C.G. Rich, S.J. Richardson and F. Rose 5]

Antheridiogen system in the fern Asplenium ruta-muraria
(Aspleniaceae: Pteridophyta)

— J.J. Schneller and Annatina Hess . 64

A new species of Huperzia (Lycopodiaceae: Pteridophyta) from India
— Papia Mondal and R.K. Ghosh Da

The Pantropical Epiphyte Ophioglossum palmatum
(Ophioglossaceae: Pteridophyta), a new record for Bolivia 75

THE FERN GAZETTE Volume 15 Part 1 was published on 30 August 1995

Published by THE BRITISH PTERIDOLOGICAL SOCIETY, c/o Department of Botany,
The Natural History Museum, London SW7 5RB

ISSN 0308-0838
Printed by J & P Davison, 3 James Place, Treforest, Pontypridd CF37 1SQ