The Illustrated Field Guide
to Ferns and Allied Plants
of the British Isles
Illustrated by Peter Edwards
6,^
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The Illustrated Field Guide
to Ferns and Allied Plants
of the British Isles
Clive J^my & Josephine Camus
Illustrated by Peter Edwards
A
Natural History Museum Publications
London
First published 1991
Natural History Museum Publications
Cromwell Road, London SW7 5BD
© British Museum (Natural History) 1991
All rights reserved. No part of this publication may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording, or otherwise, without
the prior permission of the publisher.
A Catalogue record of this book is available from
the British Library
ISBN 0 565 01172 3
Printed in Great Britain by St Edmundsbury Press Ltd
Bury St Edmunds, Suffolk
Contents
Authors’ preface iii
How to use this book iv
Introduction to ferns and allied plants vi
Glossary viii
Bibliography x
General key to British ferns and allied plants xi
Systematic arrzmgement of British ferns and allied plants 1
Clubmosses (Lycopodiaceae and Selaginellaceae) 2
Quillworts (Isoetaceae) 18
Horsetails (Equisetaceae) 26
Ferns (Ophio^ossaceae to Azollaceae) 47
Common aliens 186
Index to Latin names 192
Index to English names 194
Authors’ preface
A few years ago we produced a booklet called the BM Fem Crib
and comments from its users showed that a diagnostic guide to all
ferns (and allies) would be welcomed by those botanists and other
naturalists who still found aspects of the group difficult. At the same
time, we hope to encourage those who are curious about ferns to
get to know the group. We believed that illustrations would be
crucial to such a guide and we were fortunate that Peter Edwards
joined us in its production. Derek Adams, of the Museum’s
Photographic Unit, expertly prepared the silhouettes. We gratefully
acknowledge permission to use the figures of spores of Isoetes and
Cystopteris from Flora Iberica (C.S.I.C., Madrid, 1986).
Over the years we have enjoyed the stimulating companionship of
many friends in the British Pteridological Society and the Botanical
Society of the British Isles, both in the field and the herbarium. We
thank them all. In particular we thank Anthony Pigott and
Christopher Fraser- Jenkins for their help with Dryopteris affinis.
We are particularly grateful to Christopher Page, not only for help
with bracken and tor providing the silhouettes of that species, but
also for sharing his knowledge of ferns on many field trips.
We owe special thanks to our colleague in the Fern Herbarium,
Alison Paul, who has taken the role of Editor of this book. Her
thoroughness has enhanced the book considerably. Any mistakes
that now remain are, however, ours and not hers.
C.J. and J.C.
The Natural History Museum, London. March, 1991
- Ill -
How to use this book
This book aims to provide a tool for the amateur botanist,
naturalist or other interested person who wzmts to name a fern,
horsetail or clubmoss found vmd in Britain or Ireland. Silhouettes
and detailed drawings are annotated to guide the reader to the
distinguishing features of each species, and, as a result, detailed
written descriptions and comparisons are kept to a minimum.
Diagnostic features are printed in bold. For those who want to delve
further, or who want to compare the detailed structure and
distribution of these pteridophytes, there are more comprehensive
books available. A selection of these is given in the Bibliography.
The user should remember that plants react to their environment
as they grow and the first leaves to unfurl at the beginning of the
growing season will typically be different from those produced later;
the former are usually sterile, never bearing spores. Very young
plants (called sporelings) of many fern species produce leaves that
are not at all like those of the older plant - just like seedlings of
flowering plants. These are often impossible to identify to species.
Furthermore, the leaves of somewhat older, but still immature,
plants may be different to those of more mature ones. This is
particularly the case in ferns, where the production of fertile sporing
leaves is no true indication of age or maturity of form. Like most
organisms, ferns have in-built genetic variation as well, so that two
plants of the same species growing side-by-side may not look like
carbon-copies. Those users of this book who are already
experienced field botanists will be able to assess the variation
acceptable within a species. Less experienced people will need time
to gauge such aspects.
The ‘dichotomous ke/ leads to a species, genus or group; more
detailed keys are given in the appropriate section. Less experienced
users may prefer to flip through the book until they find a drawing
that looks something like the plant in front of them and then see
how well the two match up. If the match is not a good one, the
‘Compare with’ section on the page will lead to alternatives to try
for a better match.
Whilst we have emphasised vegetative characters throughout, to
to be certain of an identification we often have to look at critical
features of the sori, sporangia and spores. Because of this late
summer is the best time for studying most ferns. Exceptions include
the adder’s tongues, the land quillwort and some horsetails.
- IV -
How to use this book (continued)
Measurements of pinnae refer to the longest ones. Where a range
of measurements is given this is for the mature adult plant; in many
cases we give a maximum size only and young plants with smaller
(and fertile) leaves may well be found. A hand-lens with a x 10
magnification is needed as some of the characteristics described are
too small to be seen with the naked eye. Sometimes a higher
magnification: x 20 hand-lens, a dissecting microscope (x 50), or a
compound microscope (x 400) may be necessary.
Seventy-two species of pteridophyte (numbered 1-72), native or
well-established in the British Isles, are described in this book. The
arrangement and nomenclature follows that used in the herbarium
of the Natural History Museum, Lx)ndon (BM). Infraspecific
variation is described where appropriate at either the subspecies or
variety level. In those few groups where taxonomic units are
recognisable but their rank and names are not certain, we have used
the non-hierarchical category ‘morphotype’ without implying rank or
legality.
Where appropriate, we have drawn attention in the text to the
presence of hybrids in our fern flora; they are sometimes more
common than generally supposed, and may be the reason a
specimen does not match our descriptions. Hybrids are usually
morphologically intermediate between the parents, and can be
detected - and should always be confirmed - by the presence of
mostly shrivelled spores in their sporangia (seen with a x 100, or
better still, with a x 400 compound microscope). Apogamous ferns
also have some abortive spores (see p 156).
Figure 1. Contents of A, a normal sporangium; B, a hybrid sporangium
We have added six alien ferns at the end of the book in an
abbreviated format. These are species which have occurred in
more than one isolated site, and which might be confused with our
native species. As with all plant groups grown in gardens or
greenhouses, from time to time there will be occasional escapes.
These are discussed briefly on p 186.
- V -
Introduction to ferns and allied plants
Ferns are traditionally grouped with the clubmosses, spikemosses,
quillworts and horsetails as pteridophytes because, like flowering
plants, they have a vascular system of specialised cells which
conducts water and nutrients round the plant, but like mosses and
liverworts, they also reproduce by spores. Ferns differ from the
other pteridophytes (often referred to as the ‘fern allies’) in that
they bear many sporangia, the capsules within which the spores
develop, on each leaf; clubmosses, spikemosses and quillworts all
have only one sporangium per leaf, and the horsetails produce
special stalked hexagonal structures which each bear up to ten
sporangia. Fossils of pteridophytes are known from rocks some 400
million years old.
The life cycle
The life cycle of pteridophytes has two distinct phases. In the
majority of ferns a spore germinates to form an inconspicuous,
green, heart-shaped, plate-like plant called a prothallus or
gametophyte. Most British species of fern have a very similar
prothallus stage and it takes an expert to distinguish them. A few
^ecies are distinct, e.g. that of the filmy fern Trichomanes is
filamentous, resembling an alga. The adder’s tongues, horsetails and
clubmosses have minute tuber-like prothalli that live underground
and therefore lack chlorophyll. The quillworts and Selaginella are
even more specialised: their mega- and microspores germinate
within the ruptured spore wall and form a minute prothallus bearing
either archegonia or antheridia respectively. In all these cases the
gametophyte produces the sex organs; antheridia which contain
spermatozoids, and archegonia which each hold one egg-cell, are
borne on the underside or the prothallus. The spermatozoids swim
in a film of water to the egg-cells, usually to those of another
prothallus. A new and quite different plant is formed from the
resulting fertilisation. This sporophyte plant will mature to produce
the conspicuous spore-bearing leaves we examine to identity the
fern.
Structure of the fern plant
In most ferns the dominant organ is the leaf, the stem
bearing it being an erect or creeping rhizome. Like all rhizomes it
contains food reserves that enable the plant to overwinter. Erect
rhizomes will eventually fall over through lack of support, but
further growth is always upright; this condition is reierred to as
‘ascending’. In most species the actively growing area is covered
with scales (or hairs) which may be diagnostic. All leaves are
arranged spirally on the stem (rhizome); if the rhizome is slow
- VI -
Introduction (continued)
growing then the bunch of leaves at the apex will form a
‘shuttlecock’, the ch2U‘acteristic habit we associate with ferns.
Leaves arising from creeping, and often fast growing, rhizomes, are
also spirally arranged, but appear to rise sin^y or in twos or threes.
Leaves of terns range from being simple (undivided) and entire (not
cut in any way) as in hart’s tongue to Mghly dissected as in bracken.
In all ferns the sporangia arise from the leaf-blade along or at the
end of a vein. In some species the leaf bearing the sporangia is
quite different in shape, often having reduced blade tissue. In the
majority of ferns, the sporangia are borne in clusters called sori.
These vary in shape from circular to linear, or may form a
continuous line either at the m£irgin or beside the midrib. The
position and type of sorus are diagnostic. In many species the
young sporangia are protected by a membranous cover or ‘flap’
called an indusium; as the spores ripen this indusium will shrivel or
lift and allow the sporangia to dehisce.
The sporangia of the majority of ferns are stalked capsules which
have a band of thick-walled cells (called the annulus) almost
encircling the sporangium. On maturity, when the spores arc ready
for dispersal, these cells contract, rupturing the thinner-walled cells
of the sporangium wall. The annulus then acts like a hinge, the
sporangium gapes, allowing the spores to escape. The spores vary
in shape, depending on the genus or species: some are bean-shaped,
others may be tetrahedral (or spheric^).
Structure of other pteridophytes
The general features of the clubmosses, quillworts and horsetciils
have been described under those genera. The relatively large, rush-
like leaves from a corm-like stem of both aquatic and terrestrial
quillworts are similar in structure. In the clubmosses and
spikemosses, the stems are aerial and variously branched, like
flowering plants. Horsetails also have aerial stems, but these are
hollow; the pattern of epidermal cells and details of the inner
structure are both diagnostic. All horsetails are rhizomatous and
successful colonisers; the field horsetail has root tubers as
additional storage organs. The leaves of these CTOups are small
compared to most true ferns and often referred to as microphylls\
they lack complex venation, and in some cases may be even without
a midvein. The sporangia of the other pteridophytes differ in
detailed structure from ferns and all are borne on the abaxial
(upper) face of the leaf or in the leaf axil. In Selaginella and Isoetes
sporangia and spores are of two kinds (as in pillwort andAzolla).
The clubmosses (Lycopodium) have spores all of one kind.
- vii -
Glossary
Acuminate Tapering very CTadually to a point.
Anastomosing Uniting to form a network.
Arcuate Curved like a bow.
Attenuate Narrowly tapering.
Clathrate (Of scales) Of lattice appearance.
Concolorous Of one uniform colour.
Contiguous Margins of adjacent organs ± touching each other.
Coriaceous Of leathery texture.
Decumbent Prostrate with tip rising upwards.
Dimorphic Two forms, e.g. sterile and fertile leaves being
markedly different in size, shape, dissection etc.
Dichotomous Branching equally into two.
Dorsiventrally (Of a branch system) flattened to give an upper
(dorsal) and a lower (ventral) aspect.
Fasciculate Densely clustered.
Filiform Thread-like.
Flabellate Spread like a fan.
Glabrous Without hairs or scales.
Herbaceous Of thin texture.
Imbricate Overlapping like roof-tiles.
Indusium Flap of tissue covering young sorus, often membranous.
Mucronate Abruptly ended by a short point.
Ovate 2-dimensional egg-shaped.
Ovoid 3-dimensional egg-shaped.
Paraphyses Small, branched hairs among sporangia.
Patent Held at right angles to axis.
Peduncle Stalk of a cone.
Peltate Attached centrally.
Petiolate With a stalk or petiole.
Retuse With a rounded, shallowly notched end.
Receptacle That part of the sorus from which the sporangia develop.
Reticulate Like a network.
Scabrid Rou^h with many minute projections.
Scarious Thin, dry, membranous tissue lacking pigment and
appearing translucent.
Septate With cross-wzills, i.e. composed of more than one cell.
Sorus A circumscribed group of sporangia, often with an indusium.
Spathulate Spatula-shaped.
Spinulose With spine-lixe teeth.
Sporangia Capsule within which spores develop.
Stolon A ‘runner’ from the stem tnat produces a new plant.
Stramineous Straw-coloured.
Subulate Almost linear, tapering from a broad base.
Terete Cylindrical.
Verrucose (Of a spore or surface) covered with small warts.
- Vlll -
Glossary {continued)
/
2-pinnate leaf ^ 1-pinnate leaf
/
- ix -
Bibliography
Hyde, H. A., Wade, A. E., & Harrison, S. G. 1978. Welsh Ferns,
Clubmosses, Quillworts and Horsetails, ed. 6. National Museum of
Wales, Cardiff.
Jermy, A. C., Arnold, H. R., Farrell, L. & Perring, F. H. \912>. Atlas
of Ferns of the British Isles. The Botanical Society of the British Isles
£md the British Pteridological Society, London.
Page, C. N. 1982. The Ferns of Britain and Ireland. Cambridge
University Press, Ccimbridge.
Page, C. N. 1988. Ferns, their habitats in the British and Irish
Landscape. New Naturalist, Collins, London.
Phillips, R. 1980. Grasses, ferns, mosses and lichens of Great
Britain and Ireland. Ward Lock, London.
Sporne, K. R. 1975. The Morphology of Pteridophytes. ed. 4.
Hutchinson, London.
Stace, C. A. 1975. Hybridisation and the Flora of the British Isles.
Academic Press, London.
Further information
The British Pteridological Society is an international society for all
those interested in ferns and their allies at all levels.
It publishes its own journal and books, holds field meetings,
workshops and symposia, distributes spores and plants.
Details from the Membership Secretary, at the address below.
The British Pteridological Society
c/o Botany Department
The Natural History Museum
Cromwell Road
London
SW7 5BD
- X -
General key to British ferns
and allied plants
1 Plants free-floating on surface of freshwater; branches pinnate
and opposite; leaves blue-green or red, in 2 ranks, imbricate,
< 3 mm Azolla filiculoides (72)
1 Plants rooting in or on substrate 2
2 Plant with simple or branched, ± hollow, jointed stems; leaves
reduced to a vestigial whorl of teeth around nodes
Equisetum (see p 26)
2 Plants not as above 3
3 Plants with rush-like leaves, round or triangular in
cross-section 4
3 Leaves with a typical blade and stipe, arising from a terrestrial
rootstock, or leaves very small, < 10 mm, without a distinct
stipe, arranged spirally or in 4 distinct ranks along an aerial
stem 5
4 Plants producing rosettes of leaves from a short, erect,
corm-like stem; sporangia embedded in the spathulate
leafbase Isoetes (see p 18)
4 Leaves arising singly from a wide-creeping slender rhizome;
sporangia enclosed in a hard, pill-hke case attached to the
rhizome Pilularia globulifera (28)
5 Plants 2.5-25 cm high; stem aerial, creeping or ascending,
branching dichotomously; leaves < 10 mm long, arranged
spirally or in 4 ranks
Lycopodiaceae or Selaginellaceae (see p 2)
5 Plants not as above 6
6 Leaves fleshy; sporangia borne on a special structure arising
from the base of the leaf-blade Ophioglossaceae (see p 47)
6 Leaves membranous, herbaceous or leathery; sporangia either
marginal or on the underside of leaves 7
7 Leaves membranous, almost translucent, arising intermittently
from a wiry slender rhizome; sporangia in discrete pockets
on the margins of the leaf lobes
Hymenophyllaceae (see p 67)
7 Leaves thicker, arising from creeping or erect rhizomes;
sporangia in variously shaped sori on back of leaves, or if
marginal then not in discrete pockets 8
- XI -
General key (continued)
8 Plants annual; leaves usually < 10 cm, 2- to 3-pinnate, green
throughout, texture very soft; sporangia scattered along
length of or at tip of segment vein (Channel Isles only)
Anogramma leptophylla (26)
8 Plants perennial, often wintergreen; leaves entire to 4-pinnate,
if < 10 cm then not 2- to 3- pinnate and green throughout
with very soft texture; sporangia arranged in distinct
median or marginal sori 9
9 Sori marginal, with linear indusium or covered by a thin,
membranous (not just inrolled) leaf margin 10
9 Sori variously disposed on the back of the leaf 12
10 Leaves 1- to 3-pinnate, ultimate segments wedge- or fan-
shaped; stipe and rachis shiny, black
Adiantum capillus-veneris (27)
10 Leaves 1-pinnate or more divided, ultimate segments narrowly
triangular or linear; stipe and rachis green or red-brown 11
11 Leaves 0.5 to several metres tall, 2- to 3-pinnate-pinnatifid,
arising singly from an underground rhizome
Pteridium aquilinum (35a, b)
11 Leaves <0.6 m tall, 1-pinnate, arising in clusters from an erect
or short-creeping surface rhizome Pteris (A2, A3)
12 Leaves pinnatisect; sterile leaves with free veins 13
12 Leaves simple, pinnate or more compound (if sterile leaves
pinnatisect then veins anastomosing) 14
13 Leaves in clusters, strongly dimorphic; sori linear, parallel to
midrib, indusiate; rhizome erect Blechnum spicant (71)
13 Leaves arising singly, not dimorphic; sori round to oval, without
indusia; rhizome creeping Polypodium (see p 74)
14 Leaves strongly dimorphic, i.e. sterile and fertile leaves differing
markedly in general appearance 15
14 Leaves not strongly dimorphic, i.e. sterile and fertile leaves
similar or not very different in general appearance 18
15 Leaves arising singly from creeping rhizome; veins
anastomosing Onoclea sensibilis (A5)
15 Leaves in clumps or ‘shuttlecocks’ from erect rhizome;
veins free
16
General key (continued)
16 Leaves 2-pinnate; sporangia borne on special tassel-like pinnae
usually devoid of lamina tissue Osmunda regalis (24)
16 Leaves pinnate-pinnatisect or 3- to 4-pinnate; sporangia
protected by inrolled lamina 17
17 Leaves pinnate-pinnatisect Matteuccia struthiopteris (A6)
17 Leaves 3- to 4-pinnate Cryptogramma crispa (25)
18 Sorus linear or oblong; indusium a flap-like membrane attached
by its long side 19
18 Sorus ± round; indusium present or lacking, but not as above 20
19 Leaves 2-3-pinnate, tissue soft, not wintergreen; scales not
clathrate; most sori J-shaped Athyrium filix-femina (49)
19 Leaves simple to 2-pinnate, tissue tough, usually wintergreen;
scales clathrate; sori always linear or oblong
Asplenium (see p 92)
20 Leaf-blade triangular, as wide as long; rhizome slender,
long- creeping 21
20 Leaf-blade elliptic, lanceolate or ovate (if triangular then
rhizome erect); rhizome various 22
21 Leaves without glands, pinnules pinnatisect, segments
c. 1mm wide; sorus indusiate Cystopteris montana (55)
21 Leaves with or without glands, pinnules pinnatifid, segments
c. 2.5 mm wide; sorus exindusiate Gymnocarpium (51, 52)
22 Leaves glandular, smelling of lemon
Oreopteris limbosperma (38)
22 Leaves not glandular, not smelling of lemon 23
23 Indusia kidney-shaped 24
23 Indusia variously shaped or lacking 25
24 Leaf lanceolate, scant scales at base of stipe, minute hairs on
rachis and pinna midribs (x 10), margin of fertile segments
obviously inrolled Thelypteris palustris (36)
24 Leaf lanceolate to triangular, base of stipe moderately to very
densely scaly, minute hairs never present (x 10), margin of
fertile segments not inrolled Dryopteris (see p 148)
25 Indusium round, peltate, persistent 26
25 Indusium variously shaped or lacking, never round
and peltate 27
- Xlll -
General key {continued)
26 Leaf segments decreasing towards apex of leaf; veins free
Polystichum (see p 74)
26 Terminal piima as large as the lateral ones; veins anastomosing
Cyrtomium falcatum (A4)
27 Leaf-blade ovate-triangular, finely pubescent, flexed back at
45® or more Phegopteris connectilis (37)
27 Leaf-blade linear-lanceolate, glabrous, ± erect 28
28 Rhizome erect, leaves tufted or in a ‘shuttlecock’; mountain
plants on rock or in screes 29
28 Rhizome creeping; leaves arising singly or in small clusters 30
29 Leaves 18-60 cm long; indusium lacking
Athyrium distentifolium (50a, b)
29 Leaves 3-15 cm long; indusium fringed with long hairs
Woodsia (56, 57)
30 Rhizome long-creeping; leaves pinnate-pinnatisect; marsh
plants Thelypteris palustris (36)
30 Rhizome short-creeping, ascending; leaves 2-pinnate; plants of
rocks, walls, wooded ravines Cystopteris (53, 54)
- XIV -
Systematic arrangement of
British ferns and allied plants
LYCOPODIACEAE
Lycopodium
Lycopodiella
Huperzia
Diphasiastrum
SELAGINELLACEAE
Selaginella
ISOETACEAE
Isoetes
EQUISETACEAE
Equisetum
OPHIOGLOSSACEAE
Botrychium
Ophioglossum
OSMUNDACEAE
Osmunda
ADIANTACEAE
Cryptogramma
Anogramma
Adiantum
PTERIDACEAE
* Pteris
MARSILEACEAE
Pilularia
HYMENOPHYLLACEAE
Hymenophyllum
Trichomanes
POLYPODIACEAE
Polypodium
DENNSTAEDTIACEAE
Pteridium
THELYPTERIDACEAE
Thelypteris
Phegopteris
Oreopteris
ASPLENIACEAE
Asplenium
WOODSIACEAE
* Matteuccia
* Onoclea
Athyrium
Gymnocarpium
Cystopteris
Woodsia
DRYOPTERIDACEAE
Polystichum
* Cyrtomium
Dryopteris
BLECHNACEAE
Blechnum
AZOLLACEAE
Azolla
- 1 -
* Alien genus
1-7 The Clubmosses
Lycopodiaceae and Selaginellaceae
Introduction
The clubmosses proper (Lycopodiaceae) are a large and
widespread group, many terrestrial on mountains throughout the
world, others epiphytic m tropical areas. It is an ancient group that
formed large tree-hike plants m prehistoric times. Lesser
clubmosses, or, as they are more widely known, spikemosses,
(Selaginellaceae) dst equally ancient but £U"e now mostly tropical
with over 600 herbaceous species in a single genus.
Characteristics of Lycopodiaceae
Mainly herbs with stems dichotomously branched, often thick
and leathery (coriaceous), simple leaves, either all similar and
spirally arranged, or, in one ^enus (Diphasiastrum), in four ranks;
spores all of one size, borne m single sporangia attached to the base
of fertile leaves, sporophylls, similar to or different in shape and size
to sterile leaves, and arranged in ‘cones’ or in zones on the stem,
sporangia opening by a transverse slit. Four genera are represented
in the British Isles.
Characteristics of Selaginellaceae
In many ways similar to the above, but leaves more delicate;
(herbaceous); one group (subgenus Stachygynandrum), the larger
by far and given full generic rank by some, nas two kinds of leaf,
dorsiventrally arranged as two median ranks flanked by a lateral
rank of larger leaves on either side; the other (subgenus Selaginella)
has uniform leaves and looks like a smaller version of
Lycopodiaceae; spores are of two kinds in separate sporangia on
sporophylls as in Lycopodiaceae and arranged in loose or compact
‘cones’; sporanria opening by transverse slits. Only one native
species is found in the British Isles, with an African species,
S. kraussiana (Al, see p. 187), as an established alien in more
clement areas of our islands.
Field key to species
1 Leaves all similar, radially arranged in more than 4
ranks
1 Leaves ± to obviously dimorphic, arranged in 4 ranks
2 Sporophylls in distinct cones at apex of stem
2 Sporophylls in zones along stem, not in distinct apical
cones 4
-2-
U> C\ K)
The ClubmOSSCS {continued)
1-7
3 Cones sessile, leaves sharply pointed
Lycopodium annotinum (1)
3 Cones pedunculate often on branched stems, leaves drawn into
a fine white or red-brown hair-like point
Lycopodium clavatum (2)
4 Erect stems branching dichotomously, some leaves with bulbils
Huperzia selago (4)
4 Erect stems branching unequally, bulbils never present 5
5 Leaves on creeping stems curved upwards, without teeth
Lycopodiella inundata (3)
5 Leaves not curved upwards, with spinose teeth
Selaginella selaginoides (7)
6 Largest leaves ± at right angles to stem, membraneous
Selaginella kraussiana (Al)
6 Largest leaves ± parallel to stem, coriaceous 7
7 Ventral leaves trowel-shaped, petiolate; lateral leaves tapered
to stem; cones sessile Diphasiastrum alpinum (5)
7 Ventral leaves acutely subulate, sessile; lateral leaves
abruptly narrowed to meet stem; cones pedunculate
Diphasiastrum complanatum morph decipiens (6)
Hybrids
Hybridisation is common between species (and subspecies) of
Diphasiastrum in northern Europe, the offspring showing some
fertility. Because of this, there is some debate as to the status and
rank of some intermediate taxa which have been called species,
subspecies or hybrids by various authors. The yellow cypress
clubmoss (6) is probably derived from D. alpinum crossing with
D. complanatum, and has been referred to at all ranks under the
name issleri. We now believe that to be a different plant not so far
found in Britain. Our British plant is also found on mainland
Europe, but pending further investigation we have used here the
epithet decipiens, a vzirietal name given to the Gloucestershire plant
by Syme. Backcrossing of decipiens with D. alpinum may occur in
Britain (e.g. in the Malvern HiUs).
Huperzia selago with abortive spores has been found in Europe
suggesting this taxon may be a complex of closely related
‘species’. Both they, and their hybrids, may be present in Britain.
-3-
1 Interrupted Clubmoss
Lycopodium annotinum L.
LEIAVES arranged radially,
those on main stem 3-5 mm long,
lanceolate, adpressed, sparse, those
on branches 5-7 mm, crowded,
± spreading, ± coarse, entire,
sharply pointed; those
produced at the end of the
season shorter, thus
demarcating successive periods
of growth and giving the
‘interruptions’ that give the
plant its name.
SPOROPHYLLS in solitary
apical cones at the ends of erect
or ascending leafy branches,
without any form of peduncle.
HABIT: A sprawling plant with creeping primary stems, often up to
1 m long, with wide-spaced, fasciculate, ascending to erect branches
of unequal length; wintergreen.
-4-
Interrupted Clubmoss (continued)
1
CONES 2-3 cm long, at the
ends of branches, greenish
soon becoming yellow to
red-brown.
SPOROPHYLLS 1.5-2 mm,
broadly ovate, margins
scarious, toothed, apex
drawn to a fine acute point.
HABITAT: In dwarf-shrub communities (heather, bilberry)
particularly associated with ancient pine forest; a plant of well-
drained sites; in mountains rarely below 450 m (1500 ft).
DISTRIBUTION: Mainly Grampian Mts and NW Scotland with
one station in Cumbria. Absent from Ireland.
CONSERVATION STATUS: Vulnerable to upland afforestation
and possibly atmospheric pollution.
COMPARE WITH:
(2) Lycopodium clavatum in which the branches are
softer to the touch because of the flexible hair-points;
(3) Lycopodiella inundata which has more slender, only
shortly creeping stems and is a plant of wet lowland
bogs;
(4) Huperzia selago can only be confused when both
species are very young plants; Huperzia lacks the sharp
leaf point.
-5-
2 Stag’s Horn Clubmoss
Lycopodium clavatum L.
LEIAVES 5-7 x 1-1.5 mm,
radially arranged, linear-
lanceolate, pale yellow-
green, coarse, overlapping,
adpressed to stem,
margin ± entire; leaf-
tips drawn into a red-
brown or white hair,
often falling off as the
leaf ages.
FERTILE BRANCH
STEMS 8-15 cm taU,
erect, slender, bearing
few scale-like leaves,
usually forked at the
apex, with 1-3 distinct,
pedunculate, erect cones.
HABIT: Wide-creeping with a branched main stem lying close to
the ground and rooting at intervals, with unequal branches;
wintergreen.
-6-
Stag's Horn Clubmoss {continued)
2
CONES 1-3 in terminal
cluster, 1.5-3 cm long,
upright.
SPOROPHYLLS
1.5-3 mm long, ovate-
triangular, pale cream,
apex drawn out; margins
scarious, irregularly
toothed.
HABITAT: In rough mountain grassland, especially where there is
a trace of base salts; also lowland on sandy heaths, on old mine tips,
and on conifer plantation rides; to 800 m (2400 ft) alt.
DISTRIBUTION: Mostly in W and N Britain, but scattered on
heathy sites in the south; mainly in the NE in Ireland.
CONSERVATION STATUS: Vulnerable to pasture improvement
and afforestation; lost from over 170 sites in Britain alone
since 1950.
COMPARE WITH:
(1) Lycopodium annotinum, noting position of fertile
stems, cones and growth habit;
(3) Lycopodiella inundata, noting as above, and wet acid
bog habitat.
-7-
3 Marsh Clubmoss
Lycopodiella inundata (L.) J. Holub
STERILE LEAVES 4-6 mm long,
narrowly triangular to lanceolate,
somewhat fleshy and awl-shaped,
with a soft acute apex, bright
green with a glistening
appearance, ± patent and in
several ranks on upright stems,
those on creeping stems
± adpressed, tips curving away
from substrate, often appearing in
two ranks.
SPOROPHYLLS simUar to sterile
leaves, forming a solitary, terminal
ill-defined cone.
HABIT: Primary stems short-creeping, slender (<2 mm),
occasionally branched, rooting throughout its length, often decaying
during the winter of its second season thereby breaking the plant up
into small units.
-8-
Nlarsh Clubmoss {continued)
3
CONES 1-2.5 cm long,
sessile, green initially, but
becoming olive to deep yellow.
SPOROPHYLLS up to 8 mm
long, spathulate with a few
teeth at the base,
tapered tip, spreading away
from stem.
HABITAT: In wet boggy acid and nutrient-poor sites but preferring
better-drained Sphagnum hummocks or small peat cliffs, wheel ruts
etc., especially in areas of low, open vegetation or bare peat.
DISTRIBUTION; Mainly in S and E Britain and lowland sites in
Scotland N of the Forth; m Ireland, mainly in the W with records
from Armagh, Offaly and Wicklow.
CONSERVATION STATUS: Vulnerable to drainage and
afforestation; lost from over 100 sites since 1950. Protected in
Northern Ireland under the Wildlife (NI) Order, 1985.
COMPARE WITH:
(2) Lycopodium clavatum which has hair-points on its
leaves and is a plant of drier and more base-rich
habitats;
(7) Selaginella selaginoides which is similar in habit, but
has thinner leaves, and if fertile is obvious with its two
kinds of spores. It also prefers much more base-rich
flushes.
-9-
4 Fir Clubmoss
Huperzia selago (L.) Bernh. ex Schrank & C.F.P. Mart
LEAVES 2-8 mm long,
lanceolate, ± spreading, in a
tight spiral around the stem,
mid- to often yellow-green,
apex acute, margin finely
denticulate, coriaceous,
rigid, leaves on young plants
less coarse.
STERILE LEAVES
frequently produce
^bulbils’ near the base,
often seen as a ‘crown’
around the top of the
stem.
STEMS 5-20 cm tall, or
even larger, 1-3 mm
thick.
HABIT: Plant with several forked ± equal branches, rooted at a
single basal point, stems generally erect, but tending to lean (because
of exposure to wind, or lack of root support) whereupon the stems
will curve to become erect; wintergreen.
- 10-
Fir Clubmoss (continued)
4
SPOROPHYLLS similar
to sterile leaves, not
forming cones but in
zones along the stem, one
band produced each year,
followed at the end of the
season by a flush of sterile
leaves.
HABITAT: In mountain- top grassland, dwarf-heath, and on rocky
ledges, but spreading into lowland areas where damp frost hollows
give required low temperatures.
DISTRIBUTION: Mainly a northern-montane species, in Scotland
and the W of northern England, Wales and Irel2md; found scattered
in more lowland situations where air temperature inversions are
frequent, and then mainly in the SW and with a single site in
E Sussex.
CONSERVATION STATUS: Vulnerable to drainage and
afforestation.
COMPARE WITH:
(1) Lycopodium annotinum in its youngest stages before
its wide-creeping form is established, and older
vegetative plants can look similar; it has more acutely
pointed leaves and never bears bulbils.
- 11-
5 Alpine Clubmoss
Diphasiastrum alpinum (L.) J. Holub
CONES 1-2 cm long, grouped at
ends of leafy branches, with a short,
almost non-existent peduncle
bearing a few leaves intermediate
in shape and texture between those
of the cone and the leafy stem.
MAIN BRANCHES flattened,
dichotomously forked and fan-like,
the whole glaucous and
resembling a cypress tree.
SECONDARY BRANCHES
close together, often
overlapping and compact.
LEAVES 2-3(-4) mm long, all
± similar when young, lanceolate,
becoming differentiated into
opposite dissimilar pairs, forming 4
ranks.
HABIT: A low-growing, wide-creeping plant with its main stem
underground (or deep in moss or litter), with few scale-like leaves,
rooting along its length; wintergreen.
- 12-
Alpine Clubmoss (continued)
5
LATERAL LEAVES
acutely keeled, apex
reflexed, the lower half fused
to the stem, the lower part
of the keel tapering into
the stem.
MEDIAN LEAVES
narrower than lateral ones,
lanceolate and not keeled,
those on the lower
(ventral) side (best seen
on branches of the previous
year’s growth) trowel-
shaped, with an angled
petiole holding it away
from, but parallel to, the
stem (the blade often
appearing skewed in dried
specimens).
SPOROPHYLLS scale-like,
broadly ovate, drawn into a
long blunt apical tip,
greenish becoming yellow-
brown on maturity.
HABITAT: Mountain grassland and dwarf-shrub heath usually
where competition from other plants is low; rarely below 600 m
(2000 ft).
DISTRIBUTION: In the higher hills of Wales, N England and
Scotland with outliers in S Pennines (Derbyshire), Malverns
(Worcestershire); in Ireland on higher hills of the N, West Mayo,
West Galway, Offaly and Wicklow.
CONSERVATION STATUS: Vulnerable to upland grassland
improvement and afforestation.
COMPARE WITH:
(6) D. complanatum morphotype decipiens is
distinguished by its more yellow-green foliage, more
open branching and shape of the leaves, especially the
ventral leaves.
-13-
6 Yellow Cypress Clubmoss
Diphasiastrum complanatum (L.) J. Holub
morphotype decipiens (sensu Syme)
CONES 1^-2^ cm long, borne
on an erect, elongated peduncle
bearing few ovate-elliptic, scale-like
leaves.
MAIN BRANCHES very similar
to (5) D. alpinum, the whole
plant being a distinct yellow-
green colour.
SECONDARY BRANCHES
flabellate, usually longer and
more open than (5) D. alpinum.
LEAVES 2-5 mm long, all
± similar when young, lanceolate,
becoming differentiated into
opposite dissimilar pairs, forming 4
ranks.
HABIT: A wide-creeping plant with its main stem above ground
(or rarely in moss or litter), with few scale-like leaves, rooting along
its length; wintergreen.
- 14-
Yellow Cypress Clubmoss {continued)
6
LATERAL LEAVES
acutely keeled, apex
reflexed, the lower half fused
to the stem, the middle
part of the keels of
opposite pairs parallel,
curving abruptly at the
base into the stem.
MEDIAN LEAVES
narrower than later2il ones,
lanceolate and not keeled,
those underneath
(ventral leaves) (best seen
on branches of the previous
year’s growth) narrowly
triangular, sessile, with a
more acute apex.
SPOROPHYLLS ovate-
orbicular, with a shorter
more apiculate apex than
in (5) D. alpinum.
HABITAT: In undisturbed dwarf-shrub (heather-bilberry) heath;
reaches lower altitudes than D. alpinum (>270 m, 800 ft).
DISTRIBUTION: Often associated with areas of Caledonian pine
forest in Scotland; not so far confirmed for Wales, possibly a
hybrid population in Worcestershire; not recorded from Ireland.
CONSERVATION STATUS: Vulnerable to moor-burning and
conversion of lowland heaths.
COMPARE WITH:
(5) Diphasiastrum alpinum, which has different sterile
leaves, sessile cones and is of a general glaucous colour.
Diphasiastrum complanatum subsp. complanatum: this subspecies has so
far not been found in the British Isles but could be found in similar sites at
low altitude. It has very small appressed, triangular, acutely pointed ventral
leaves with cones on tall, erect peduncles very similar to those of
Lycopodium clavatum.
- 15-
7 Lesser Clubmoss
Selaginella selaginoides (L.) Beauv. ex Schrank
& C.F.P. Mart.
MAIN STEMS prostrate,
occasionally branched,
terminating in a cone on an
erect shoot, 2-10 cm tall and
bearing dormant vegetative
shoots at its base.
CONES ill-defined, 2-3 cm
long, increasing in length as
sporangia mature and
dehisce.
STERILE LEAVES
spirally arranged, 2-3 mm
long and crowded on the
dormant shoots, up to
5 mm and well-spaced on
fertile stems, lanceolate,
with few spinose teeth on
margin, apex acute,
texture thin.
HABIT: A low, prostrate, moss-like plant with erect, unbranched,
cone-bearing stems that have several dormant branches at their
base which are wintergreen and will develop into fertile branches
the following year.
- 16-
Lesser Clubmoss (continued)
1
SPOROPHYLLS similar to
sterile leaves, but wider;
forming loose terminal
cones.
SPORANGIA and
SPORES of two kinds on
separate sporophylls;
those containing mega-
spores at the base of the
cone, 3-4-lobed, opening
into the same number of
valves; those containing
microspores in the upper
part of the cone, globose,
with two valves.
MEGASPORES salt-
grain sized (c. 600 )
(x 50), verrucose, ash-grey.
MICROSPORES
30-38 imm (x 400),
deep orange.
HABITAT: In damp flushes and seepage areas which contain a
significant amount of base-rich salts; associated with snow patches
in mountains; in sand-dune slacks at sea-level.
DISTRIBUTION: A northern-montane species; in Britain not
south of Merioneth; in Ireland not south of Clare-Carlow except for
one site near Wexford town.
CONSERVATION STATUS: Vulnerable to drainage and change
of land-use; lost from over 70 sites in Britain and from 35 in Ireland
since 1950.
COMPARE WITH:
(3) Lycopodiella inundata (small plants) has thicker,
± curved leaves without teeth;
Similar also to some sterile mosses (Atrichwn,
Mnium spp.) but these are more delicate and have no
basal branches.
- 17-
8-10 The Quillworts
Isoetaceae: Isoetes
Introduction
Quillworts are an ancient and very distinct group of plants
related to clubmosses rather than true ferns. Two species are
normally submerged aquatics, and probably very common in the
lakes where recorded although usually they are difficult to see
without diving. The third is a terrestrial mediterranean plant
reaching only the SW of Britain.
Characteristics of Isoetes
Stem short and corm-like, bi- or tri-lobed in cross section; roots
basal, dichotomously branched; leaves in a rosette from sunken
stem apex, tapering from a broad, sheathing base; sporangia
solitary, spherical or ovoid, 5-8 mm wide, embedded in inner face
of leaf bases and partially covered by membraneous tissue,
containing either large spores {megaspores) which can easily be seen
by the naked eye and are diagnostic in their sculpturing, or smaller
microspores which are closer in size to fern spores (both are found
on the same plant, but not on the same leaf).
Spore dispersal of a submerged aquatic can be helped by water
currents, but plants growing deep in the closed system of a lake
cannot spread easily to another lake. In storm conditions those not
too deeply immersed may be dislodged or otherwise break up, and
fertile leaves washed up on shore with spores being dispersed by
birds or wind. The land quillwort may have its decaying sporangia
broken up by soil invertebrates and the spores may get washed
through the soil or brought to the surface and dispersed by wind
and animals’ feet.
Field key to species
1 Plant terrestrial, leaves dying down in April/May histrix (10)
1 Plant normally submerged, leaves present throughout the year
2
2 Leaves tapered from the base, flaccid, clinging together when
removed from the water; megaspores spinulose
echinospora (9)
2 Leaves not tapered from base, stiff, remaining rigid when
removed from water; megaspores with blunt anastomosing
ridges lacustris (8)
- 18-
The Quillworts {continued)
8-10
Hybrids
I. echinospora and I. lacustris are rarely found growing in the
same lake. When they do grow together, as for example they do at
Cogra Moss, Cumbria, they may hybridise (= /. x hickeyi Taylor &
Luebke). The offspring appear intermediate in morphology, and
each megasporangium contains several much smaller, often flatter,
abortive megaspores. There is evidence from cytology and
isoenzyme studies that hybrids of the same parentage have
doubled their chromosomes and formed fertile plants in lakes in the
French Pyrenees. These were described by nineteenth century
botanists as Isoetes brochonii Motelay. Some plants with large
megaspores and blunt tubercles on their upper faces from Scottish
and Welsh lakes may prove to be this species and need further
investigation.
- 19-
8 Common Quillwort
Isoetes lacustris L.
LEAVES 10-45 cm long,
c. 2.5-12 mm wide,
± cylindrical, containing
four septate air canals
throughout their length,
tapering only slightly in
the last few centimetres
towards a rather blunt
asymmetrical point,
rigid, erect, somewhat
brittle, remaining stiff
when taken out of the
water.
LEAF-BASE broad,
clasping, with a wide
membraneous margin.
HABIT: A submerged, evergreen, aquatic plant with a rosette of
leaves arising from a corm-like, 2-lobed stem embedded in the lake
bottom substrate; roots brownish, dichotomously branched. Often
recorded only as storm-washed material on lake shore, but usually
present in some quantity, forming a dense turf on deeper lake
bottoms.
-20-
Common Quillwort {continued)
8
SPORANGIUM at base of
fertile leaf, containing either
mega- or microspores.
MEGASPORES
500-570 fjim diam.,
greyish-white when dry,
the mature spore wall
showing anastomosing
ridges 20) that
resemble brain-coral.
NB: When considerable
variation in spore size is seen
within a sporangium, spores
may be abortive and the plant
a hybrid.
HABITAT: In upland tarns and lakes, optimally at around 2 m
depth, although occasionally to 6 m in very clear water, in varying
substrates from coarse silt to fine mud, in waters of low nutrient
content. Although it cam tolerate more nutrients than
7. echinospora, competition both from other vascular plants and
algae may be a limiting factor in its distribution.
DISTRIBUTION: Throughout N to SW Scotland and the
S Uplands, the English Lake District, N and W Wales, generally
associated with acid rocks; in Ireland, mainly in the N and W.
I CONSERVATION STATUS: Vulnerable to nutrient enrichment
from upland moorland ‘improvement’
I COMPARE WITH:
(10) I. echinospora which has leaves that taper from the
base and spiny megaspores.
' Superficially similar to Littorella uniflora, which has stolons, white roots
and a spongy tissue throughout its leaf (not the four channels as above).
-21-
9 Spring Quillwort
Isoetes echinospora Durieu
LEAVES 3-25 cm long,
c. 1.5-3 mm wide near the base,
± cylindrical or with a slightly
flattened upper (adaxial) face,
containing 4 septate air canals,
tapering almost immediately
from the base to a slender,
acute point, initially erect, but
soon bending away from the
centre of the rosette.
in shallow water sites
often appressed to the
substrate (looking starfish-
like), flaccid and clinging
together when taken out of the
water.
LEAF-BASE broad, clasping, with
a wide membraneous margin.
HABIT: A submerged aquatic evergreen plant with a rosette of
leaves arising from a corm-like, 2-lobed stem, embedded in the lake
bottom substrate; roots brownish, dichotomously branched. Often
recorded only as storm-washed material on lake shore where
occasional plants will re-establish themselves and continue growing,
but usually present in some quantity, though rarely forming
continuous swards in deeper water as /. lacustris can.
-22-
Spring Quillwort (continued)
9
SPORANGIUM at base of
fertile leaves, containing
either mega- or microspores.
MEGASPORES
420-450 /Jim diam.,
chalky-white, densely
spiny on all faces (x 20,
only seen when dry and
mature - late summer
and autumn).
NB: When considerable
spore size variation is seen
within a sporangium, spores
may be abortive and the
plant a hybrid.
I HABITAT: In upland lakes, optimally at around 2 m depth, not
1 recorded as deep as /. lacustris; in varying substrates from sand and
t coarse silt to fine mud, usually in acid waters of very low nutrient
, content although tolerating relatively high sodium and magnesium
I levels; rarely found in the same lakes as /. lacustris.
1 DISTRIBUTION: Scattered throughout the range of/, lacustris but
I frequently at lower altitudes and in maritime situations; its rareness
I is the Cumbrian lakes is difficult to explain; in Ireland, confined to
I the western seaboard.
« CpNSERVATION STATUS: Possibly increasing due to
i acidification of lakes, yet vulnerable to nutrient enrichment from
; farmland or moorland ‘improvement’; losses are difficult to estimate.
( COMPARE WITH:
(9) I. lacustris, megaspore diameter and sculpturing
(only seen when mature in late summer/ autumn at
X 20) is the only sure way of determining the majority of
specimens, although the star-like habit and tapered leaf
is a good indicator of /. echinospora.
' Superficially similar to the flowering plants Littorella uniflora, and
particularly Subularia aquatica, both of which have white roots and thin
stolons.
-23-
10 Land Quillwort
Isoetes histrix Bory
LEAVES 2-10(-15) cm long,
0.5-2 mm wide, linear or slightly
tapering from the base to a blunt
but narrow point, often arcuate,
triangulcU" in cross-section with the
upper side flattened, with a single
longitudinal air canal, lacking the
septa seen in the air chambers of
the other species; green, although
somewhat translucent towards the
base.
LEAF-BASE spathulate with a
broad translucent margin which
continues up the leaf for 1-2 cm;
the area bearing the
sporangium becoming black
and hardened at the base and
a 3-lobed, corm-like stem, appearing very early in the year
(February/March) and (regardless of the availability of water) that
will die back to the corm by the end of April or mid May; in
exposed conditions leaves will lie flat and merge with other
associated species, in less exposed and marshy conditions, leaves are
erect and rush-like.
-24-
Land Quillwort (continued)
10
FERTILE LEAVES
produced later in the
growing season (April).
SPORANGIUM containing
either mega- or microspores.
MEGASPORES
350-470 fim , with fine,
frequently coalescing
warts (x 50).
1 HABITAT: In areas which retain water during the winter or which
1 have a steady flow of ground water during that time, but which also
. dry out in the summer; often on S- or SW-facing maritime cliff tops,
on gentle valley slopes facing the sea, or in imperceptible hollows at
‘ sea-level; usually on shallow silty or peaty soils over serpentine or
I granite.
1 DISTRIBUTION: A Mediterranean species that spreads up the
Atlantic seaboard to the Channel Islands (Guernsey and Jersey) and
l to the Lizard Peninisula.
( CONSERVATION STATUS: A very local species in Britain but
well documented and known to be in some quantity where it grows.
’ Most sites are in protected areas.
(COMPARE WITH:
There is no other species of terrestrial quillwort with which it
can be confused in Britain but it can be mistaken for a number
of maritime turf plants like the spring squill (Scilla vema),
young sea thrift (Armeria maritimd) and, in the Channel Islands,
the sand crocus (Romulea columnae) that have similar leaves.
None, however, have a large longitudinal canal in the leaf or the
characteristic horny leaf-bases of I. histrix.
-25-
11-19 The Horsetails
Equisetaceae: Equisetum
Introduction
These curious plants are the relicts of an ancient family
known through fossils from as early as 325 million years ago, the
geological period (Upper Carboniferous) when the remains of
plants became the vast coal deposits that we use today.
Characteristics of Equisetum
Lx)ng-creeping, underground rhizome producing aerial stems at
close intervals and forming a colony; aerial stems with hollow
internodes, the size of the hollow and the arrangement of the
different tissues and canals when seen in transverse section being
diagnostic for species; surface ridged longitudinally; silica deposited
in the epidermis (in sometimes diagnostic patterns); stems
appearing jointed, with leaves in whorls and reduced and fused into
a sheath at the stem nodes, the number of leaves equals the number
of stem ridges; branches absent or produced at the nodes; fertile
stems emerging before sterile ones, similar or dissimilar to sterile
stems, with an apical cone composed of whorls of hexagonal, peltate
sporangiophores bearing sporangia; spores green, each with four
hygroscopic strap-like structures called ‘elators’ .
NOTE: ‘feeP bv gently squeezing the stem internode;
assess ^rough/ smooth’ by running a fingernail down the
stem internode.
Field key to species
1
1
2
2
3
3
4
4
Stem not green, never branched with a cone at apex, only fertile
stems present 2
Stem green, with or without cone and/or branches (or if stem
white then with dense whorls of green branches) 3
Stem with few (4-6) sheaths, cone 1-4 cm long arvense (15)
Stem with many (6-12) sheaths, cone 4-10 cm long
telmateia (19)
Branches present, few, or many in a whorl
Branches absent
Stem internodes white, c. 1 cm diam.
Stem internodes green, less than 1 cm diam.
4
11
telmateia (19)
5
-26-
The Horsetails (continued)
11-19
5 Branches again branched; sheath teeth with a broad russet-
brown scarious margin, adhering together sylvaticum (17)
5 Branches not branched; or if so, the sheath teeth without
scarious margins 6
6 Lowest branch internode equal to or longer than adjacent stem
sheath 7
6 Lowest branch internode shorter than adjacent stem
sheath at lower nodes 8
7 Stem smooth, sheath teeth lacking scarious margin
arvense (15)
7 Stem rough, sheath teeth with broad, white, scarious margin
pratense (16)
8 Sheath teeth with broad, white, scarious margin 9
8 Sheath teeth with scarious margin very narrow or lacking 10
9 Branches only at base of stem; stem internodes rough, with
angular ridges (x 10); stomata visible (x 10) as a single row
of white dots either side of each trough between stem
ridges variegatum (13)
9 Branches throughout length of stem; stem internodes smooth,
with rounded ridges; stomata visible (x 10) as white dots
scattered in each trough between stem ridges palustre (18)
10 Stem smooth, collapses easily when squeezed fluviatile (14)
10 Stem slightly rough, feels firm ramosissimum (12)
11 Stem very rough, sheath teeth shed leaving crenelated upper
margin to sheath hyemale (11)
11 Stem smooth or slightly rough, sheath teeth persistent 12
12 Stem collapses easily when squeezed, no dark band developing
at base of sheath fluviatile (14)
12 Stem firm, dark band developing at base of sheath 13
13 Sheath teeth with scarious margin narrow or lacking
ramosissimum (12)
13 Sheath teeth with broad, white, scarious margin
variegatum (13)
Hybrids
For a list of, and notes on, hybrid horsetails, see p. 46.
-27-
11 Rough Horsetail
Equisetum hyemale L.
STERILE STEM 70-100 cm
X 3-6 mm diam., very
rough, overwintering,
unbranched.
FERTILE STEM similar to
sterile one and emerging at
same time.
CONE 7-15 mm, apex
sharply pointed, partly
concealed by teeth of
uppermost sheath.
SPORES shed late winter to
eairly spring the year after
the cone was formed.
HABIT: Plant forming dense, and often extensive, colonies from an
underground rhizome; wintergreen, but young shoots will die in
hard frosts.
-28-
Rough Horsetail (continued)
STEM with 10-30 ridges;
stem feels soft, hollow
2/3 - 3/4 diam.
SHEATH green at first,
becoming pinkish-grey in
middle and eventually
with a black band at base
that broadens with age.
SHEATH TEETH lost as
stem expands, leaving a
dark, crenelated upper
margin to sheath and a
‘pagoda’ of whorls of
teeth at stem apex.
INTERNODES become
inflated so that stem
seems narrowed above
and below sheaths.
HABITAT: Lowland wet valley sides and riverbanks with mineral-
and base-rich substrate.
DISTRIBUTION: Throughout the British Isles, but scattered
and scarce south of the Mersey-Humber line.
CONSERVATION STATUS: Vulnerable to drainage and
increased gr2izing pressure.
COMPARE WITH:
(14) E. fluviatile, which has a smooth stem and
persistent sheath teeth.
-29-
12 Branched Horsetail
Equisetum ramosissimum Desf.
STERILE STEM
50-120 cm X 3-9 mm, very
variable, branched or
unbranched.
BRANCHES on aerial
stems mainly in centre
1/3 of stem, upcurved.
FERTILE stem similar to
sterile one and emerging at
the same time.
CONE apex sharp-tipped,
6-12 mm, usually only on
main stem.
HABIT: Plant often forming a colony of erect shoots from a
branched underground rhizome; tufted appearance from strong
branching at base of shoots when in restricted rocky habitats;
wintergreen but often dying in second year.
-30-
Branched Horsetail {continued)
12
STEM green, with 10-20
distinct ridges, slightly
rough; stem feels firm,
hollow 1/2 - 2/3 diam.
SHEATH TEETH black,
with scarious margin very
narrow or lacking, very long
(up to 5 mm) and pointed,
persistent, dark band
develops at base.
BRANCH INTERNODE
6-10 angled in TS, 0.5-1 mm
wide.
BRANCH TEETH
± straight, long and pointed,
dark.
LOWEST BRANCH
INTERNODE much shorter
than adjacent stem sheath.
HABITAT: In rough grassland on well-drained sandy soil, not far
from sea.
DISTRIBUTION: Only two sites known in the British Isles;
definitely introduced with ballast in Lincolnshire.
CONSERVATION STATUS: The Lincolnshire site is threatened
by flood protection schemes but the species is protected under the
Wildlife and Countryside Act, 1981.
COMPARE WITH:
(13) E. variegatum, which has shorter sheath teeth with
broad, scarious margins.
-31-
13 Variegated Horsetail
Equisetum variegatwn Schleicher ex Weber & Mohr
STERILE STEM 5-60 cm x
1.5-2 mm diam., (or up to
80 cm X 3 mm in robust
forms which are frequently
found in Irish fens); main
stem decumbent, often
branched at base, rarely
branched above and if so
then usually only one
branch at a node.
FE^RTILE STEM similar to
sterile one and emerging at
same time.
CONE sharply pointed,
5-7 mm.
SPORES shed late spring to
early summer.
HABIT: Plant bearing decumbent, prostrate or erect shoots from
an underground rhizome, forming small, but often dense, colonies;
wintergreen.
-32-
Variegated Horsetail {continued)
13
STEM with 6-8 angular
ridges, slightly rough;
stem feels firm, hollow
c. 1/3 diam.; stomata
visible (x 10) as a single
row of white dots either
side of each trough
between stem ridges.
SHEATH TEETH
persistent, with a broad,
white, scarious margin
and a dark mid-line
ending in a dark hair-
point which is soon lost;
black band develops at
base of sheath teeth;
nodes and internodes may
be orange-tinted.
HABITAT: In open, fairly basic, damp sandy sites from lowland
heaths and dune-slacks, on alluvial terraces beside mountain
streams to high mountain ledges; 0- over 900 m (3000 ft) alt.
DISTRIBUTION: Widespread but uncommon.
CONSERVATION STATUS: Not unduly threatened.
COMPARE WITH:
(18) Equisetum palustre, which may produce basal
branch shoots of similar appearance (especially if
grazed), but these are smooth.
-33-
14 Water Horsetail
Equisetum fluviatile L.
STERILE STEM 100-
150 cm X 2-8 mm diam.,
very variable in size and
number of branches;
form in open sites
unbranched, that in
shady sites with a few,
short upcurved branches
in whorls in middle i/3 of
stem.
FERTILE STEM shorter
than sterile stem and
emerging at same time,
branches developing later in
upper 1/3 of stem.
CONE blunt-tipped,
10-20 mm.
SPORES shed early to mid
summer.
HABIT: Plants forming large colonies of erect shoots from a wide-
creeping underground rhizome; wintergreen.
-34-
Wstcr HorSCtsil {continued)
STEM with 10-30 very
indistinct ridges;
collapsing easily when
squeezed, hollow 4/5
or more diam.
SHEATH TEETH
persistent, needle-like,
brown, occasionally with
a very narrow, scarious
margin, mostly free,
occasionally 2 adhering
at margins; sheath
1 HABITAT; In wet ditches, slow-flowing rivers, marshes, alluvial
1 mires, forming the dominant member (or with Carex rostrata) in the
; succession to colonise open water in upland acid lakes; tolerant of
I up to 1.5 m water.
I DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
< COMPARE WITH:
(15 X 14) E. X litorale, which has a much firmer shoot,
i.e. the central cavity is much smaller.
-35-
15 Field Horsetail
Equisetum arvense L.
STERILE STEM
10-90 cm X 3-5 mm diam.,
green, br<mched.
BRANCHES whorled, many
£md unbranched (or very
rarely branched again),
upcurved.
FERTILE stem 10-25 cm,
emerging earlier than sterile
stem and very short-lived,
whitish-brown, unbranched;
sheaths 4-6, large, chaffy.
CONE blunt-tipped,
10-40 mm.
SPORES shed late
spring/early summer.
HABIT: Plant forming a colony of erect stems in sheltered sites or
prostrate stems in exposed sites, from an underground rhizome;
dying down in winter.
-36-
Field Horsetail (continued)
15
STEM with 8-20 ridges,
smooth, stem feels firm,
hollow less than 1/2
diameter.
SHEATH TEETH
persistent, black tips, no
scarious margin.
V
BRANCH
INTERNODE
4-armed in TS,
1-2 mm wide.
///
BRANCH TEETH usually
green throughout,
spreading away from
branch axis, free part
1-2 mm long.
LOWEST BRANCH
INTERNODE equal to or
longer than adjacent
stem sheath.
HABITAT: Fields, hedge banks, waste land and gardens; mainly on
sandy soils but also seen on river gravels and in peaty high-altitude
flushes.
DISTRIBUTION: Common throughout the British Isles; an almost
uneradicable weed.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(16) E. pratense, which has a very rough stem;
(17) E. sylvaticum fertile stems may lack branches and
look very similar to E. arvense, but may be distinguished
by having groups of sheath teeth attached along their
margins;
(18) E. palustre, noting especially lowest branch
internode length.
-37-
16 Shade Horsetail
Equisetum pratense Ehrh.
STERILE STEM
10-30 cm X 1-3 mm, pale,
almost glaucous green;
outline blunt-topped or
rounded when fully
expanded.
BRANCHES many,
unbranched, slender,
flexed down.
FERTILE STEM 10-35 cm,
sheaths numerous, stem
initially green and
unbranched, then either
withers when spores shed, or
produces whorls of branches
and resembles sterile stem.
CONE rare, blunt-tipped,
15-20 mm.
SPORES shed early
summer.
HABIT: Plant producing erect stems from a wide-creeping rhizome,
forming colonies; dying down in winter.
-38-
Sh^dc HorSCtsil (continued)
16
STEM with 8-20 ridges,
very rough, feels very firm,
hollow c. 1/2 diameter.
SHEATH TEETH
persistent, with a black
centre and a conspicuous
broad, white, scarious
margin.
BRANCH TEETH often
brown tipped, free part
0.5 mm, adpressed to
branch axis.
lii
lIUlNiit,,
mim
BRANCH INTERNODE
3-armed in TS, 0.5-1 mm
wide.
LOWEST BRANCH INTERNODE
very much shorter than adjacent stem
sheath at lower nodes, but longer at
upper nodes.
HABITAT: Undisturbed stream and river banks with light shade,
I occasionally in open moorland at higher altitudes where drainage or
‘ spring water percolates, in wet flushes in woodland; requires some
( calcium and base-rich salts.
1 DISTRIBUTION: Not common, in scattered localities in Scotland,
’ N Ireland and N Pennines of England.
CONSERVATION STATUS: Vulnerable in its lowland sites due to
afforestation.
1 COMPARE WITH:
(15) E. arvense, which feels smooth and lacks the
scarious margin on the sheath teeth; also see branch TS;
(17) E. sylvaticum, which has spreading branch teeth
and branched branches; and see also branch TS.
-39-
17 Wood Horsetail
Equisetum sylvaticum L.
STERILE STEM 10-50 cm
(occasionally larger in lush
sites) X 3-6 mm diam., green.
BRANCHES many,
branched, gracefully
drooping, grass-green.
FERTILE STEM as tall as,
and emerging at same time
as sterile shoots, whitish,
with numerous sheaths, but
initially no branches; whorls
of branches produced as
cone matures, finally
resembles sterile stem.
CONE blunt-tipped,
15-25 mm.
SPORES shed late
spring/early summer
HABIT: Plant producing often large stands of erect stems from an
underground much-branched rhizome; dies down in winter.
Wood HorSCtsil {continued)
STEM with 10-18 ridges, each
main ridge topped by two
small ridges of silica, smooth
to fairly rough, feels firm,
hollow 1/4 - 1/3 diam.
SHEATH TEETH
persistent, thin, dark
central stripe with a very broad,
russet-brown, scarious margin,
attached at margins into groups
of 2 or 3.
BRANCH INTERNODE 3(-4)-armed
in TS, 0.5-0.6 mm wide.
BRANCH TEETH c. 1 mm long,
slightly spreading, green, slender,
acutely pointed.
LOWEST BRANCH
INTERNODE always longer than
adjacent sheath.
HABITAT; On humid, sheltered moorland stream banks and wet
woodlands, especially conifer plantations in western areas of high
rainfall.
DISTRIBUTION: Widespread, becoming more scattered in the
drier eastern part of Britain.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(15) E. arvense, which has simple branches 1-2 mm wide;
(16) E. pratense, which has unbranched branches and
broad, white, scarious margins to the sheath teeth.
-41-
18 Marsh Horsetail
Equisetum palustre L.
STERILE STEM typically
15-50 cm long x
1-3 mm diam. (but a stunted
form c. 10 cm, with very few
branches occurs in high
altitude mountain flushes).
BRANCHES few,
upcurved, unbranched.
FERTILE STEM similar to
sterile one, emerging at
same time.
CONE blunt-tipped,
15-25 mm.
SPORES shed in summer.
HABIT; Plant bearing erect shoots from an underground rhizome;
usually dying down in winter.
♦
-42-
Nlsrsh Horsetail (continued)
STEM very smooth, with
5-9 ridges; stem feels very
firm, hollow less than 1/4
diameter, stomata visible as
white dots scattered in each
trough between stem ridges
(x 10).
SHEATH TEETH
persistent, black, with a
conspicuous broad,
white, scarious margin
surrounding the central
^gothic-arch’ shaped
central black triangle.
BRANCH INTERNODE
4-6 angled in TS,
c. 1 mm wide.
LOWEST BRANCH
INTERNODE much
shorter than adjacent
stem sheath.
BRANCH TEETH short,
clasping branch axis,
usually blackish tipped, with
a scarious margin.
HABITAT: In wet or damp places e.g. ditches, marshes, bogs, sand-
dunes, verges of metalled roads in acid moorland areas; requires
some base-rich salts.
DISTRIBUTION: Widespread in the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(15) E. arvense, especially in high altitude wet flushes,
noting longer lowest branch internode;
(13) E. variegatum, which develops a black band at base
of sheath teeth.
-43-
19 Great Horsetail
Equisetum telmateia Ehrh.
STERILE STEM
30-100 cm or more
X 10-30 mm diam., white.
BRANCHES many,
unbranched, pale green,
upcurved.
FERTILE STEM 15-25 cm,
emerging earlier than sterile
stem, white, and very short-
lived, sheaths numerous with
large, brown, chaffy teeth.
CONE 50-80 mm, blunt-
tipped.
SPORES shed late spring.
HABIT: Plant with erect shoots from a creeping underground
rhizome forming large, often dense, colonies; dying down in winter.
-44-
GrCSt Horsetail {continued)
/ ° O '
i : ; • ;
/il : 1 II
||
Y_o 0/
STEM with 20-40
inconspicuous ridges,
smooth, easily compressed,
hollow 2/3 or more diameter.
SHEATH TEETH narrow,
pale brown, with scarious
margins at base, mostly free,
but some joined at margins
in groups of 2 or 3; sheath
grey-green.
BRANCH INTERNODE
0.5 mm wide with 4-5 bi-
angled ridges in TS,
ridges with very small
saw- like teeth (x 20).
LOWEST BRANCH
INTERNODE shorter than
adjacent stem sheath.
BRANCH TEETH 4-5,
c. 2 mm, green, linear-
lanceolate, ± straight,
adpressed.
HABITAT: On banks, roadsides and in damp, base-rich places.
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
No other British Horsetail can be confused with this
species.
-45-
11-19 Hybrid Horsetails
The following hybrids ( | ) have been found in the British Isles:
E. X bowmanii C.N. Page = (17) E. sylvaticum x
(19) E. telmateia
E. X dyed C.N. Page = (14) E. fluviatile x (18) E. palustre
E. X font-queri Rothm. = (18) E. palustre x (19) E. telmateia
E. X titorale Kuhlew. ex Rupr. = (15) E. arvense x
(14) E. fluviatile
E. X mildeanum Rothm. = (16) E. pratense x (17) E. sylvaticum
E. X moorei Newm. = (11) E. hyemale x (12) E. ramosissimum
E. X rothmaleri C.N. Page = (15) E. arvense x (18) E. palustre
E. X trachyodon A. Braun = (11) E. hyemale x
(13) E. variegatum
hye
These hybrids may be formed wherever the parent species grow
in reasonable proximity. Shoot fragments may be dispersed and
give rise to new colonies elsewhere. E. x moorei is known in the
British Isles only from Wicklow in Ireland, although one parent,
E. ramosissimum, is not known from that island. Hybrid horsetails
are generally rare and often known only as isolated populations.
They show a mixture of morphological characters of both parents
and have abortive cones. E. x dycei and E. x litorale are more
commonly found, but are often confused with each other.
Three further hybrids (4) involving British species have been
recorded for mainland Europe, but two of these {E. arvense x
E. pratense and E. arvense x E. telmateia) need confirmation. They
could be found in suitable situations in the British Isles.
-46-
■23 Moonwort and Adder’s Tongues
Ophioglossaceae
Introduction
These rather fleshy-looking and ungraceful plants are very
untypical ferns. They are thought to be members of one of the
earliest groups of ferns to have evolved. There is no fossil evidence
to support this idea, but it is widely accepted because they show
some features common to the early prehistoric plants. Members of
this group are the only extant ferns whose young leaves do not have
the typical fern habit of developing as a crozier.
Characteristics of Ophioglossaceae
Small terrestrial plants with an underground stem often
spreading by meems of stolons; leaves fleshy, with two portions, the
leaf-blade and a fertile structure {spike) £u-ising from the base of
that blade, in Ophioglossum a simple structure bears a fused, double
row of sporangia near the apex, in Botrychium a branched structure
bears clusters of spor2mgia like bunches of grapes; sporangia thick-
walled and without a row of thickened cells {annulus), dehiscing by
a horizontal slit to release several thousand spores from each
sporangium.
Field key to species
1 Blade of le2if with 4-8 pairs of fan-shaped pinnae, spike
1- to 2-pinnate with sporangia terminal on ultimate
segments Botrychium lunaria (20)
1 Blade of leaf not divided, ovate to lanceolate, spike not
divided and the sporangia fused in a double row 2
2 Leaves appearing in autumn, dying down in spring, leaf-blade
8-23 + mm long, thick, fleshy or waxy, spores shed in early
spring Ophioglossum lusitanicum (23)
2 Leaves appearing in spring, dying down in summer/autumn,
leaf-blade usually larger, if <20 mm then texture thin,
spores shed in summer 3
3 Leaf-blade flat, held erect; leaves arising singly
Ophioglossum vulgatum (21)
3 Leaf-blade convex, reflexed and held almost parallel to the
ground; leaves usually arising in pairs
Ophioglossum azoricum (22)
-47-
20 Moonwort
Botrychium lunaria (L.) Swartz
PLANT 5-25 cm, fleshy, with
2 main leaf portions: a
sterile portion or leaf-blade,
and a fertile portion, the
spike.
LEAF-BLADE 2.5-14 cm,
held away from the vertical,
linear-oblong, pinnate,
pinnae 4-8 opposite
pairs, fan-shaped,
margins entire to deeply
crenate; with a single
terminal ± lobed pinna.
SPIKE shorter to longer
than the blade, held
vertically, 1- to 2-pinnate.
STIPE succulent, stem-like.
HABIT: Solitary plants arising from an underground, upright
rootstock; dies down at the end of the summer and frequently lies
dormant for several seasons before re-appearing.
-48-
Moonwort (continued)
SPORANGIA not arranged
in separate sori but occurring
along margins of ultimate
segments which almost
completely lack lamina
tissue.
HABITAT: In open places in grassy uplands and old meadows,
sometimes in old dune-slacks or mine tips, usually where base-rich
conditions are present; from sea-level to c. 1000 m (3350 ft).
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
This can be confused with no other British pteridophyte.
Forms with highly lacerated pinnae have been
erroneously recorded as the Central European
B. matricariifolium, which is unlikely to grow in our
oceanic climate.
-49-
21 Adder’s Tongue
Ophioglossum vidgatum L.
PLANT 8-30 cm, or more in
shady situations, fleshy,
leaves typically arising
singly.
LEAF-BLADE up to
15 X 6 cm, flat, held
erect, broadly ovate-
lanceolate to ovate,
widest below the middle,
base attenuate to cordate
and often clasping the spike.
SPIKE shorter to
slightly longer than the
leaf-blade.
HABIT: Plant with an underground rootstock with creeping stolons
producing new plants and often forming extensive colonies,
emerging in spring and dying back in autumn.
-50-
Adder’s Tongue {continued)
21
SPORANGIA 11-44.
SPORES released in
summer.
jl HABITAT: Tolerant of a wide range of soil types; in old damp
meadow pastures, chalk downlands, old chalk 2md marl pits,
' sand-dune slacks, damp peaty sites, on light sandy soils amongst
bracken and in woods, copses and hedgebanks, and on deep peat
j s soils of fenland mowing marshes.
1 1 DISTRIBUTION: Throughout the British Isles.
(CONSERVATION STATUS: Not threatened.
(COMPARE WITH:
(22) O. azoricum, which typically has two leaves per
plant, with the leaf-blades reflexed towards the
horizontal; it also appears and dies down earlier in the
growing season.
-51-
22 Small Adder’s-tongue
Ophioglossum azoricum C. Presl
PLANT 3-8 cm, fleshy,
leaves typically arising in
pairs from an
underground rootstock.
HABIT: Plant with an upright underground rootstock with creeping
stolons producing new plants and often forming large colonies,
emerging in early spring and dying back in summer.
-52-
Small Adder s Tongue {continued)
22
SPORANGIA 4-13(-17).
SPORES released in early
summer (May- June).
: HABITAT: Short, grazed turf on tops of cliffs and sea crags, and in
s sand-dune slacks.
I DISTRIBUTION: Scattered localities in W and N Britain from the
Scilly Isles to Caithness and the Orkneys.
( CONSERVATION STATUS: Not immediately threatened, but
c coastal sites are vulnerable.
(COMPARE WITH:
(21) O. vulgatum which typically has only one leaf per
plant;
(23) O. lusitanicum a rarer species known only from a
few coastal sites and whose leaves appear in autumn and
die down in the spring.
-53-
23 Least Adder’s Tongue
Ophioglossum lusitanicum L.
PLANT 1-1.5 cm, fleshy,
typically 2 leaves per
plant, spreading apart.
LEAF-BLADE 8-23(-38)
X 1.5-4(-6) mm long,
typically held reflexed,
and then often adpressed
to the ground, but may
be more erect, narrowly
elliptic, widest at the
middle, narrowing to the
base, yellow-green, thick,
very fleshy, almost waxy
in texture.
SPIKE usually shorter to
occasionally longer than the
blade.
/ jll
HABIT: Plant with an underground rootstock with creeping stolons
developing new plants and often forming large colonies, emerging in
autumn and dying back in spring.
-54-
Lcsst Adder s Tongue {continued)
23
SPORANGIA 3-8(-13) pairs.
SPORES released in early
spring (February-March).
f HABITAT: In short turf on the moist peaty or sandy soil of
r relatively exposed, usually S- or SW-facing coastal rock downs and
c cliff-tops.
I DISTRIBUTION: Only a few sites on St. Agnes in the Scilly
Isles and Guernsey in the Channel Islands.
(CONSERVATION STATUS: Vulnerable because of limited sites.
IProtected in Britain under the Wildlife and Countryside Act, 1981.
(COMPARE WITH:
(22) O. azoricum, whose leaves are less waxy, broader
and emerge in spring and die back in late summer.
-55-
24 Royal Fern
Osmunda regalis L.
LEAVES 60-120 (-300) cm, erect, croziers
covered with fine matted cinnamon-brown
hairs which soon drop away; fertile leaves
bearing, in the upper part, pinnae
devoid of lamina to giving a tassel-like
appearance.
LEAF-BLADE ovate-oblong, 2-pinnate,
pale green, texture thin, but tough.
PINNAE up to 50 cm long,
linear-oblong.
PINNULES 5-15 cm long,
up to 1.5 cm broad, linear,
often lobed slightly at the
base, apex acute; margins
entire, wavy.
STIPE c. 1/2 leaf
length, without hairs
or scales.
HABIT: Leaves clustered on an erect branching rhizome that
eventually forms massive clumps of many crowns; dying down in
winter.
-56-
Royal Fern {continued)
24
SPORANGIA massed
along pinnule midribs on
very narrow pinnule
lamina, pear-shaped, all
maturing ± together and
gaping open by an apical
slit to release the spores.
SPORES green and short-
lived; shed early to mid
summer.
NOTE: Because the spores
are green, mature fertile
leaves appear green; if
brown, then the sporangia
have already dehisced.
I HABITAT: Found in a wide range of acidic wetland habitats from
open bogs to wet woodland, ledges of sea cliffs and beside lakes and
rivers; at altitudes usucJly less than 50 m (170 ft), occasionally
I higher in maritime areas of Ireland.
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: May be locally threatened by
drainage.
( COMPARE WITH:
Mature plants can be confused with no other British
fern but young plants of Osmunda may look like
(A5) Onoclea sensibilis; the veins of this species form a
network, those of Osmunda are forked and open to the
margin.
-57-
25 Parsley Fern
Cryptogramma crispa (L.) R.Br.
LEAVES ovate-triangular,
bright green, rather leathery.
STERILE LEAVES
15-20 cm, 3-(4-)pinnate,
arching.
FERTILE LEAVES taller
than sterile leaves, up to
25 cm, 2- to 3-pinnate,
erect.
STIPE 1/2 or more leaf
length (relatively longer in
fertile leaf), slender, brittle,
green becoming brown at
the base, with a few
scattered scales.
SCALES long-triangular,
pale brown.
HABIT: Leaves densely clustered on a branching, semi-erect
rhizome that gives rise to a group of crowns; dying down in the
winter.
-58-
Parsley Fern (continued)
25
STERILE ULTIMATE
SEGMENTS broad,
wedge-shaped, often
overlapping, margin finely
toothed.
FERTILE ULTIMATE
SEGMENTS linear or
linear-oblong, not
overlapping, margin
rolled under to form a
false indusium.
SORI along ends of veins,
without a true indusium,
protected by inrolled margin
of pinnule segment.
HABITAT: Amongst acidic scree and boulders on steep well-
drained slopes, drystone walls, occasionally amongst bilberry, from
100-1200 m (300-4000 ft) altitude; a definite calciruge.
DISTRIBUTION: Common in the Lake District of England, in
Wales and Scotland; rare in SW England on the high granite moors,
and similarly so in E Ireland.
CONSERVATION STATUS: Not threatened.
I COMPARE WITH:
No other British fern has this resemblance to Parsley
(Umbelliferae).
-59-
26 Jersey Fern
Anogramma leptophylla (L.) Link
LEAVES up to 18 cm,
yellow-green, delicate; the
earliest are lax, markedly
shorter than later ones,
trilobed and sterile, later
leaves are held erect,
become progressively more
dissected reaching
2-pinnate-pinnatifid and are
fertile.
STIPE 1/2 - 2/3 leaf length,
straw-coloured becoming
shiny dark brown.
SCALES few, hair-like,
1-cell wide (x 20).
HABIT: Small tufted plants produced annually, frequently from a
perenniating gametophyte; sporophyte usually dying during the dry
summer period.
-60-
Jersey Fern (continued)
26
HABITAT; Open areas of steep, sunny lane sides that are well-
drained but catch prevailing rain-bearing winds and where there is
little competition from other plants.
DISTRIBUTION: A Mediterranean species that is known from one
site in Guernsey and a few in Jersey.
CONSERVATION STATUS: Vulnerable because of limited sites
and because lane banks are frequently cleared.
COMPARE WITH:
There is no fern in Britain with which this species can be
confused, but it could be overlooked as a seedling of
Umbelliferae or a crucifer because of its leaf shape and
herbaceous texture.
-61-
27 Maidenhair Fern
Adiantum capillus-veneris L.
LEAVES up to 30+ cm,
delicate, red in crozier stage,
becoming bright green with
expansion, 1- to 3-pinnate.
STIPE shiny black or dark
brown, with a few scales at
the base.
SCALES brown, clathrate,
narrowly triangular, very
attenuate.
HABIT: Erect or pendulous fronds produced in a tuft from a
slender short-creeping rhizome; usually dying back in winter, but
may over-winter in very sheltered sites.
-62-
Maidenhair Fern (continued)
ULTIMATE
SEGMENTS wedge- or
fan-shaped, without a
midrib, sides straight
and the outer margin of
sterile ones notched, that
of fertile ones folded
under.
SORI on vein endings of the
membranous, outer margins of
pinnule segments which are
folded under and act as a Talse
indusium’.
HABITAT: Frost-free, wet, calcareous sites: on sheltered coastal
cliffs, inland on mortared walls in warm sites such as walls of
heated greenhouses.
DISTRIBUTION: Scattered sites in Ireland, Wales, SW and
W England as far north as the Isle of Man and Cumbria. Usually
established from the spores of cultivated plants at inland sites.
CONSERVATION STATUS: Coastal sites for this species are safe
but inland limestone habitats are vulnerable to quarrying.
COMPARE WITH:
No other British fern has wedge- or fan-shaped ultimate
leaf segments without an obvious midrib and with sori
protected by the leaf margin.
-63-
28 Pillwort
Pilularia globulifera L.
LEAVES c. 1 mm thick
X 3-8 cm, or to 30 cm where
plant totally and constantly
submerged, comprising a
filiform, terete leaf, erect or
often Eircuate or twisted,
arising at intervals of
5-10 mm from the whitish,
slender, branched, creeping
rhizome, mid- or yellowish-
green.
SPOROCARP (spore-
bearing organ) arising from
the base of the leaf, up to
2 mm in diam., globose,
covered with appressed
septate hairs when young
which are lost as it matures,
green at first, turning brown,
then blackish, eventually
horny and persistent,
splitting in late
summer/autumn into four
almost equal segments, each
containing a sorus
embedded in mucilage.
HABIT; A plant which can develop a network of slender
rhizomes forming an extensive and dense turf, or when in moss or
with other herbs may be seen as isolated leaves arising from a far-
creeping rhizome; wintergreen but cut back by extreme frosts.
-64-
Pillwort {continued)
28
SORUS contains two kinds
of sporangia which
dehisce their respective
spores into the mass of
mucilage surrounding them
and in which germination
and fertilisation takes place
within a short time of
dehiscence.
MICROSPORANGIA
contain many
microspores (x 400).
MEGASPORANGIA
contain a single ovoid, slatey
^ey megaspore (x 10, but
visible to the naked eye).
HABITAT: A lake-margin plant which can withstand submersion
for extended periods; thrives in habitats with little other
competition,characteristic of disused brick-clay pits, dew and other
man-made ponds, especially where poached by animals; at the edges
of reservoirs, occasionally in peaty pools and in heathland hollows
on sand if water contains some nutrients; from 0 - 400 m (1200 ft).
DISTRIBUTION: scattered throu^out the British Isles but scarce
in the peaty moorlands of Scotland; in Ireland in the west and north.
CONSERVATION STATUS: An endangered species found only in
western Europe; Britain is one of the remaining strongholds, and
here, 60% of the sites have been lost due to habitat change.
Protected in Ireland under the Flora (Protection) Order, 1980 and
the Wildlife (NI) Order, 1985.
COMPARE WITH:
There is no other species with which it can be confused,
although because of its rhizomatous rush-like nature it
could be mistaken for a species oiJuncus. The young
leaves of Pilularia, however, show the coiled crozier
typical of a fern.
-65-
29-31 The Filmy Ferns
Hymenophyllaceae
Introduction
Growing in small or large colonies or intermingled with mosses
and liverworts on steep streamsides, ravines, rocks or tree boles in
sites where the humidity is constantly extremely high.
Characteristics of Hymenophyllaceae
Small to medium-sized, evergreen plants with translucent,
membraneous, 2-3-pinnate leaves produced at intervals on a wire-
like, creeping rhizome. Sori in pockets at the leaf margin.
Field key to species
1 Leaves dark green, 2-3-pinnate; pinna base decurrent on
petiole; sorus a flask-shaped, lipless pocket at leaf edge,
with receptacle protruding as a bristle as sorus matures
Trichomanes speciosum (31)
1 Leaves olive- or blue-green, 2-3-pinnatifid; pinna base not
decurrent on petiole; sorus an ovoid or orbicular lipped
pocket at leaf edge, with receptacle always concealed
within it 2
2 Leaves olive-green, linear in outline, arching away from
substrate; lips of sorus not toothed
Hymenophyllum wilsonii (30)
2 Leaves blue-green, ovate-oblong in outline, hanging down
laxly over substrate; lips of sorus toothed
Hymenophyllum tunbrigense (29)
Hybrids
There is evidence of hybridisation between Hymenophyllum
tunbrigense and H. wilsonii in Madeira, but hybrids have not been
recorded in the British Isles.
-66-
The Filmy Ferns {continued)
29-31
Gametophytes of Hymenophyllaceae
The ecology and distribution of the gametophyte (or prothallus)
stage of ferns is not discussed in this book because of the problems
of identification, Gametophytes are usually found close to the
sporing plant which, from a distribution record point of view, are
easier to identify. Thus the ecological requirements of the
gametophyte appear to be very much the same as the larger
sporophyte, always assuming that there is sufficient moisture to
maintain growth and permit fertilisation, A gametophyte normally
dies when the sporophyte arising from it has become well
established as an independent plant, although the gametophyte of
the Jersey fern {Anogramma leptophylld) is known in some instances
to have survived from year to year when the associated sporophyte
dies during a period of summer drought.
The Hymenophyllaceae exhibit a phenomenon seen in only a few
families of ferns: the gametophyte has been able to establish itself
and maintain viable populations in areas unsuitable for the
sporophyte, thereby extending the geographic range of the species.
The gametophyte of Trichomanes speciosum, which is filamentous,
has been recorded in Britain over a much wider range than the
spore-bearing plant but appears to lack sex-organs and the ability to
produce plants of the next generation. It does, however, produce
gemmae as small, single-celled bodies which break off from the
filaments of the gametophyte and thereby propagate the plant. It
may be seen as mats, often extensive, of green alga-like filaments,
usually in very dark recesses in caves and below overhangs.
-67-
29 Tunbridge Filmy Fern
Hymenophyllum tunbrigense (L.) Sm.
LEAVES 2-5 (-11 or
more) cm long.
LEAF-BLADE ovate-
oblong, 1-pinnate,
translucent, blue-green.
STIPE 1/3 - 1/2 leaf length,
wiry, ± glabrous, winged
only near the top.
HABIT: Leaves hanging laxly down over substrate, borne
at intervals on a thin, wiry, long-creeping rhizome; wintergreen.
-68-
Tunbridge Filmy Fern (continued)
29
PINNAE ± evenly
divided, with 5-11
segments on large
pinnae; margins and tips
flat, serrated; bases
decurrent as a wing on
either side of rachis.
SORUS at edge of pinna
segments, a small, orbicular,
lipped pocket, held in
plane of leaf; margins of
lips (4ndusium’)
irregularly toothed;
sporangia concealed within
pocket.
SPORES green.
CELLS between veins of
pinna segments typically
± square (c. 60 x
39 /Jim ), with c. 30-40
chloroplasts per cell
(x 100).
HABITAT: Often growing in luxuriant masses on steep rock faces
and tree boles at low altitudes (up to c. 400m, 1300 ft) where the
humidity is constantly very high.
DISTRIBUTION: Widespread in W Britain and in Ireland with
outliers in the Weald, W Yorkshire and Northumberland.
CONSERVATION STATUS: Vulnerable to woodland clearance
that exposes sites to drying winds; not threatened in its main areas.
COMPARE WITH:
(30) H. wilsonii, which holds the sori out from the plane
of the leaf and has entire margins to the lips of the sori.
-69-
30 Wilson’s Filmy Fern
Hymenophyllum wilsonii Hooker
LEAVES 3-10 (or more) cm
long.
LEAF -BLADE linear,
1-pinnate, translucent,
olive-green.
STIPE not usually more
than 1/3 leaf length, wiry,
± glabrous, winged only
near the top.
HABIT: Leaves arching away from substrate, borne at
intervals on a thin, wiry, long-creeping rhizome; wintergreen.
-70-
Wilson’s Filmy Fern (continued)
30
PINNAE ± unilaterally
divided (upper side),
with 3-5 segments on
large pinnae; margins
and tips recurved,
serrated; bases decurrent as
a wing on either side of
rachis.
SORUS at edge of pinna
segments, a small, ovoid,
lipped pocket, held out
from plane of leaf;
margins of lips
(^indusium’) entire;
sportmgia concealed within
pocket.
SPORES green.
CELLS between veins of
pinna segments typically
± rectangular (c 94 x
39 ^tm), with c. 60-80
chloroplasts per cell
(x 100).
HABITAT: Often growing in scattered patches on steep stream
banks, rock faces and tree boles or amongst mountain scree (up to
c. 1000 m, 3300 ft) where the humidity is constantly very high.
DISTRIBUTION: Widespread in W Wales, the English Lake
District and Scotland, with local sites in SW England; throughout
Ireland but mostly in the SW.
CONSERVATION STATUS: Not threatened, but rare outside the
British Isles.
COMPARE WITH:
(29) H. tunbrigense, which holds sori in the plane of the
leaf and has toothed margins to the lips of the sori.
-71-
31 Killarney Bristle Fern
Trichomanes speciosum Willd.
LEAVES up to 45 cm long.
LEAF-BLADE broadly
ovate to ovate-lanceolate,
2-3-pinnate, translucent,
dark green.
PINNAE triangular-ovate,
finely divided, margins
entire, bases decurrent as a
wing on either side of the
rachis and stipe.
STIPE about 1/2 leaf
length, dark translucent
green, ± glabrous, narrowly
HABIT: Leaves arching down over substrate, borne at intervals on
a slender, long-creeping and branching rhizome that bears dark,
hair-like scales; wintergreen.
-72-
Killarney Bristle Fern (continued)
31
SORUS on the acroscopic
edge of pinna segments,
a small flask-shaped
pocket with entire
HABITAT: On rocks and in crevices in very sheltered sites through
which water is constantly running.
DISTRIBUTION: Very few localities in W Britain from Cornwall
to W Scotland; mainly in the west of Irelemd.
CONSERVATION STATUS: Protected in Britain under the
Wildlife and Countryside Act, 1981; and in Ireland under the Flora
Protection) Order, 1980 and the Wildlife (NI) Order, 1985.
COMPARE WITH:
(29, 30) Hymenophyllum species, which have smaller,
less divided leaves, sori with ‘indusial’ lips and
thread-like rhizomes.
-73-
32-34 The Polypodies
Polypodiaceae: Polypodium
Introduction
Often forming large colonies on steep banks, boulders, cliff faces,
old walls or epiphytic on mature broad-leaved trees growing in
areas of constantly high humidity.
Treated as one species in Britain in earlier floras, and now
realised to be a complex of two species ( Polypodium cambricum
and/*, vulgare), their fertile hybrid (P. interjectum), and the sterile
hybrids and backcrosses with the parents. Often very difficult to
separate and requiring observation of microscopic characters (the
number of indurated, i.e. thick-walled, cells in the annulus and the
number of unthickened basal cells between the annulus and
sporangium stalk).
Characteristics of Polypodium
Stout, scaly, creeping rhizome with small to medium, firm to
leathery, oval to triangular, pinnatisect, wintergreen leaves with a
green, glabrous stipe 1/3 - 1/2 leaf-length, each borne on a raised
area (podium) of the rhizome. Sori round to oval, without indusia,
regularly spaced on either side of the midrib of the leaf segment.
Field key to species
1 Leaves typically narrowly lanceolate to linear; annulus distinctly
deep reddish-brown when sporangium is yellow, visible as a
long, thin, red-brown line at x 10; rhizome scales narrowly
triangular with acute, but not long or wispy, apex
vulgare (32)
1 Leaves narrowly ovate to deltoid; annulus indistinct or brown
when sporangium is yellow, if visible then as a short,
thickish, dark brown line at x 10; rhizome scales narrowly
triangular with long or wispy apex 2
2 Leaves broadly ovate to deltoid; usually only a few sori,
restricted to upper 1/3 leaf; annulus visible when
sporangium is yellow as a short, thickish, dark brown line at
X 10; rhizome scales narrowly triangular with a long, wispy
apex cambricum (34)
2 Leaves narrowly ovate to oval; sori usually many, over upper
1/3 - 2/3 leaf; annulus not obvious at x 10 when sporangium is
yellow; rhizome scales narrowly triangular with long, but not
wispy, apex interjectum (33)
-74-
The Polypodies (continued)
32-34
Hybrid Polypodies
The following hybrids ( | ) have been found in the British Isles:
P. xfont-queri Rothm.
= (34) P. cambricum x (32) P. vulgare
P. X mantoniae Rothm.
= (33) P. interjectum x (32) P. vulgare
P. x shivasiae Rothm.
= (34) P. cambricum x (33) P. interjectum
vul
int
1
1
1
The hybrids are intermediate between the parents emd often show
1 hybrid vigour by growing extremely large. Because of the difficulty
’ in identifying the parents, it is essential that suspected hybrids are
checked for abortive sporangia (which remain small and unopened)
' and spores (which are rarely shrivelled in this genus, but are
( colourless in contrast to the normal yellow spores).
I P. X mantoniae is the commonest hybrid and often forms very large
c colonies on banks 2md tree boles.
} P. X shivasiae is completely sterile; all the spores in a sporangium
will be abortive.
-75-
32 Common Polypody
Polypodium vulgare L.
LELWES 5-25 cm long,
mid-green, new leaves
produced early summer.
LEAF-BLADE narrowly
lanceolate to linear (but
juvenile or stunted leaves
triangular), pinnatisect to an
obvious herringbone pattern.
LEAF SEGMENTS
c. 2-4 cm long, entire or
barely serrate, tips rounded,
lowest pairs not inflexed.
RHIZOME SCALES
narrowly triangular with
acute, but not long and
wispy, apex.
HABIT: Dense colonies of leaves produced at intervals from a
stout, scaly, branched, creeping rhizome; wintergreen.
-76-
Common Polypody {continued)
32
SPORANGIUM with
annulus red-brown
(conspicuous at
X 10), indurated cells
(7-) 10-14 (-17), long and
narrow (22 -28 Atm x
60-80 fjim) (x40), 1 basal
cell (x 40) [arrowed] .
SPORES ripe in summer.
HABITAT; A weak calcifuge reaching fair altitudes, on peat banks,
trees, drystone walls and tops of rocky outcrops and cliffs.
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(33) P. interjectum, which has more attenuate scales
and 7-9 indurated annulus cells;
(34) P. cambricum, which has paraphyses in the sori and
spores ripening in early spring.
-77-
33 Intermediate Polypody
Polypodium interjectum Shivas
LEAVES 15-60 cm long,
mid-green, new leaves
produced late summer
and autumn.
LEAF-BLADE narrowly
ovate to oval, piimatisect.
LEAF SEGMENTS c. 5 cm
long, usually slightly serrate,
tips tapering or bluntly
rounded, lowest pairs
somewhat inflexed.
RHIZOME SCALES
narrowly triangular with
long, but not wispy, apex.
HABIT: Dense colonies of leaves produced at intervals from a
stout, scaly, branched, creeping rhizome; wintergreen.
-78-
Intcrrncdistc Polypody (continued)
33
SORI initially oval, on
upper 1/3 - 2/3 of leaf,
paraphyses lacking.
SPORANGIUM with
pale annulus (not
conspicuous at x 10),
indurated cells (4-) 7-9
(-13), fairly long and not
very narrow (28-35 fJLm x
76 -86 yu-m) (x 40), 2-3
basal cells (x 40)
[arrowed] ,
SPORES ripe
summer to autumn.
HABITAT: A weak calcicole on rocky banks and cliffs and
mortared walls; on trees in maritime sites and on sand-dunes where
salt-laden winds provide the necessary calcium and magnesium
salts.
DISTRIBUTION: Throughout the British Isles.
( CONSERVATION STATUS: Not threatened.
(COMPARE WITH:
(32) P. vulgare, which has more indurated cells in the
annulus;
(34) P. cambricum, which has paraphyses in the sorus
and spores ripening in early spring.
-79-
34 Southern Polypody
Polypodium cambncum L.
LEAVES 5-50 cm long,
yellow-green, new leaves
produced
autumn/winter.
LEAF-BLADE broadly
ovate-deltoid often with a
long, narrow apical segment,
pinnatisect.
LEAF SEGMENTS up to
7 cm long, usually serrated
and with acute apices, lowest
pair inflexed.
RHIZOME SCALES
narrowly triangular with a
long wispy apex.
HABIT; Dense colonies of leaves produced at intervals from a
stout, scaly, branched, creeping rhizome; turning yellow and dying
down in late spring or early summer.
-80-
Southern Polypody (continued)
34
SORI oval, on upper 1/3 of
leaf, paraphyses present.
SPORANGIUM with a
dark brown annulus
(conspicuous at x 10 at
an early stage when the
rest of the sporangium is
yellow), indurated cells
(4-) 5-10, short and
broad (21-26 /jim x
81-100 Atm) (x 40), 3-4
basal cells (x 40).
[arrowed] ,
SPORES ripe in early
spring.
HABITAT: Base-rich rocks usually on steep slopes or cliffs, walls
and occasionally on trees in maritime sites.
DISTRIBUTION: Throughout lowland areas of S and W Britain,
N to Argyll; scattered throughout Ireland.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(32) P. vulgare, which does not have paraphyses in the
sori and has only one basal cell below the annulus;
(33) P. inteijectum, which has narrower leaves and does
not have paraphyses in the sorus.
-81-
35a Bracken
Pteridium aquilinum (L.) Kuhn
morphotype aquilinum
Genetically a very variable taxon; at least three subspecies have been
described in Britain, but their relationships and taxonomy need clarilying.
We describe here two forms (as ‘morphotypes’ because their rank is still
in debate) that can be identified, but warn that there is considerable
hybridisation within the species complex. A further morphotype,
atlanticum, (C.N. Page, as subsp.) a frost-sensitive, soft-textured form
with a succulent stipe and white hairy leaf is less distinct, and is included
here within (35a) until further work clarifies its position.
LEAVES 1-2.5 m long, occasionally much longer in shady
situations, erect; young croziers densely covered with white
hairs and very few r^ous hairs.
LEAF-BLADE oblong-lanceolate to ovate-triangular, 2- to
3-pinnate-pinnatifid, ± erect, texture tough, often leathery in
exposed situations, ± matt, almost grey-green.
PINNAE up to 70 cm long,
perpendicularly inserted
and horizontally
inclined, developing
sequentially towards the
apex of the leaf, ovate-
lanceolate, pinnate-
pinnatisect, apex attenuate,
drooping.
RACHIS ± glabrous, pale
green, bearing nectaries at
pinna junctions.
STIPE dark at base pale
red-brown to green above,
succulent and
mucilaginous until leaf
fully expanded.
SCALES lacking, rhizome
tip and emerging leaves
bearing hairs only.
HABIT: Leaves arising intermittently from a deep underground
branched rhizome forming large and characteristic stands; dying
in winter, forming a pale brown litter as the stipes collapse.
-82-
Bracken {continued)
35a
PINNULES linear-
lanceolate, apex acute or
attenuate to caudate.
ULTIMATE SEGMENTS
to 15 mm long, linear,
adnate at the base, apex
acute or obtuse, margins
inrolled; often densely
covered below with many
colourless (appearing
white) and scattered
rufous hairs, best seen
on unfurling croziers.
SORUS marginal and
continuous round the entire
pinnule, covered by a
membranous ‘false
indusium’ formed from the
leaf margin and which is
present even if the leaf
segment is sterile.
INDUSIUM membranous,
fringed, continuous round
pinnule.
! HABITAT: A ubiquitous and aggressive species which colonises
I open areas e.g. heaths, rough and hill grassland, old pasture,
roadsides, woodland rides, etc.; prefers deep (>25 cm) sandy or
^ well-worked loamy soils, even on calcareous substrates if soil deep
I enough, but usually absent from heavy clays.
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: In no way threatened but itself often
. a threat to rare heathland species.
COMPARE WITH:
(35b) P. aquilinum morphotype latiusculum which can
be recognised by the conspicuous red-brown hairs on
unfurling leaves, the deflexed, ± deltate leaf-blade with
acutely inserted pinnae and the thin stipe.
Very young plants often get established on walls and old building sites and
resemble Dryopteris species, but presence of fine hairs instead of scales on
the rhizome apex confirms it as Bracken.
-83-
35b Northern Bracken
Pteridium aquilinum (L.) Kuhn
morphotype latiusculum (sensu C.N. Page)
LEAF-BLADE 2- to
3-pinnate-pinnatifid, broadly
deltate, sub-ternate,
deflexed to a low angle
from its junction with
the stipe, texture
herbaceous, ± matt,
grass-green.
LEAVES 0.8-1.2 m long,
occasionally longer, erect;
young croziers covered
with dense pale rufous
hairs and some scattered
colourless hairs.
PINNAE up to 50 cm long,
obliquely inserted, not
rotated from the plane of
the rachis, developing
almost simultaneously
throughout the leaf,
ovate-triangular, apex
attenuate, not drooping.
RACHIS ± glabrous, pale green or stramineous, bearing
nectaries at pinna junctions,
STIPE dark at base, pale red-brown to green above, tough
and wiry, weakly mucilaginous.
SCALES lacking, rhizome tip and emerging leaves bearing
hairs only.
HABIT; Leaves arising intermittently from a deep underground
branched rhizome forming large and characteristic stands; leaves
turning deep red-brown through winter.
-84-
Northern Bracken (continued)
35b
PINNULES linear-
lanceolate, apex acute or
attenuate to caudate.
ULTIMATE
SEGMENTS similar in size
and shape to (35a) but
covered below with many
rufous and a few
colourless hairs, best
seen on unfurling
croziers.
SORUS marginal and
continuous round the entire
pinnule, covered by a
membranous ‘false
indusium’ formed from the
leaf margin and which is
present even if the leaf
segment is sterile.
INDUSIUM membranous,
fringed, continuous round
pinnule.
HABITAT: Associated with forests of native Pine (Pinus sylvestris)
and Juniper (Juniperus communis) and adjacent roadside verges on
deep acidic soils.
DISTRIBUTION: Recorded from Strath Spey and a few other
W Scotland ancient pine forests.
CONSERVATION STATUS: Not threatened as long as forest
protected.
COMPARE WITH:
(35a) P. aquilinum morphotype aquilinum which has
more white than red-brown hairs on unfurling leaves, a
taller, more linear-lanceolate, erect leaf-blade,
horizontally orientated pinnae inserted at right-angles,
and a thicker, more succulent stipe.
Enzyme analysis has shown that this form is not identical to the plant
described under this name from N America, but it may be the same as the
northern European variety called latiusculum.
-85-
36 Marsh Fern
Thelypteris palustris Schott
STERILE LEAVES
appearing first in
spring, up to
c. 80 cm.
FERTILE LEAVES
appearing in early
summer, up to
c. 150 cm.
LEAF-BLADE lanceolate,
abruptly tapered at apex,
1-pinnate-pinnatisect, lowest
pairs of pinnae only slightly
shorter than middle pinnae,
pinnae of fertile lecif
narrower than those of
sterile leaf, pale green.
STIPE up to 1/2 leaf length
(relatively longer in fertile
leaf), slender, green,
becoming black and with a
few scales at the base.
SCALES few, broadly
triangular, apex acute,
brown, soon lost.
HABIT: Leaves few, at intervals (sometimes several centimetres
apart) on a long-creeping, branched, thin rhizome; dying down in
late autumn.
-86-
Marsh Fern {continued)
36
PINNAE held flat in leaf
plane, margins of segments
rolled imder, partly
concealing sori, no obvious
glands on either surface,
minute hairs scattered on
mid-rib and veins.
SORI round, mid-way
between pinna segment mid-
vein and margin, appearing
to cover whole of pinna
segment’s lower surface as
sori mature.
INDUSIUM small, delicate,
round-oblong to kidney-
shaped, margin irregular and
glandular; soon lost.
HABITAT: Mires, fens and reedswamps, particularly inPhraffnites
and Cladium communities.
DISTRIBUTION: Throughout the British Isles, becoming very rare
in Scotland.
CONSERVATION STATUS: Threatened by land drainage; at least
-40% of sites lost in England and Wales since 1950.
(COMPARE WITH:
The long, slender stipe and delicate leaf arising from a
thin, wide-creeping rhizome make this species
distinctive.
-87-
37 Beech Fern
Phegopteris connectilis (Michx) Watt
LEAVES (15-) 20-40 cm
long.
LEAF-BLADE triangular
to broadly ovate, tapered
to an acute apex,
1-pinnate-pinnatisect,
lowest pair of pinnae
deflexed forward out of
plane of blade, whole
blade often reflexed to
lay almost horizontal,
finely hairy on both surfaces,
light green (as in young
beech leaves).
PINNAE lanceolate, lowest
pair attached by midrib only,
ipper ones adnate.
STIPE 1/2 - 2/3 leaf length,
minutely hairy, very few
scales at base.
SCALES ovate, colourless,
soon lost.
HABIT; Leaves few, at intervals from a slender, branched,
creeping, underground rhizome; dying down in late autumn.
Bccch Fern (continued)
37
PINNA-SEGMENTS
oblong, apex rounded.
SORI round, very close to
margin and mainly around
sinus, without indusium.
HABITAT: Not in beech woods! In colonies on moist, shady banks
in woodland and streamsides where water percolates or on moist
patches on rocky slopes and cliff ledges in mountains up to c. 600 m
(2000 ft).
DISTRIBUTION: Lxjcally frequent in upland Wales, N England and
Scotland, rare and scattered in S England and Ireland.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
The shape and the hairiness of this species is distinct
and it cannot be confused with any other.
-89-
38 Lemon-scented Fern
Oreopteris limbosperma (Bellardi ex All.) J. Holub
LEAVES 30-120 cm long.
LEAF-BLADE
oblanceolate-elliptic tapered
to acute apex, 1-pinnate-
pinnatisect.
PINNAE linear-lanceolate,
gradually tapered to apex,
lowest pinnae gradually
decreasing in size, yellow-
green.
RACHIS and PINNA
MIDRIBS with a few scales
and many fine glandular and
non-glandular hairs; pale
yellow-green.
STIPE up to 1/5 leaf length,
with sparse covering of
scales.
SCALES colourless,
appearing white or pale
brown.
HABIT: Leaves forming a ‘shuttlecock’ on a short, branched
rhizome; dying down early in winter.
-90-
Lcmon-sccntccl Fern {continued)
38
PINNA SEGMENTS
linear-oblong, shallowly
lobed, with minute glands
covering lower surface
and giving a lemon scent
when brushed.
SORI very close to
pinnule segment margin.
INDUSIUM rudimentary or
completely absent; when
present small, irregular in
shape with a glandular
margin.
HABITAT: Damp, peaty sites on mountain sides, steep stream
banks and gullies, and open acidic woodland.
DISTRIBUTION: Throughout the British Isles, but commoner
in upland districts of N Wales and W Scotland and scarce in
S England.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(61, 62, 63) Dryopteris species may be confused in their
younger stages but they lack glands and markedly
decrescent pinnae;
(A6) Matteuccia struthiopteris which has a narrower,
more elliptic leaf completely lacking glands.
-91-
39-48 The Spleenworts and their relatives
Aspleniaceae: Asplenium
Introduction
The Spleenwort genus Asplenium includes here the Hart’s
Tongue, sometimes put into a separate genus Phyllitis, and the
Rustyback, sometimes segregated as the genus Ceterach.
Although superficially distinct, we find their characteristics within
the range of Asplenium when viewed on the wider European basis
and prefer to treat them in that genus, as is usually the case in
Continental Floras.
Characteristics o/ Asplenium
Predominantly tufted plants of rocky substrates and walls,
usually with many crowns and a short-creeping rhizome, covered at
its apex with clathrate scales (i.e. scales composed of cells which
are pigmented only on their radial walls and therefore appear as a
lattice window) [Fig. A]; leaves, with few exceptions, of a hard,
tough texture, shiny on the upper surface; sori linear-oblong on
lateral veins of leaf segment, covered by a linear indusium which is
pushed back by the developing sporangia, often becoming confluent
and appearing to cover the whole leaf; spores with irregular crests.
An interrelated reticulate complex of diploid and tetraploid
species in which the tetraploid taxa are frequently difficult to
separate from their diploid
progenitors. In these cases
spore size is important and
the length of the inner wall
or exospore (as shown in the
adjacent figure [B]) should
be measured in water (at
least a mean of 30 spores) to
compare with those given
here.
Field key to species
1 Leaves undivided, entire scolopendrium (39)
1 Leaves forked, trifoliate, pinnate or more dissected 2
2 Leaves forked, trifoliate or 1-pinnate 3
2 Leaves 2- or 3-pinnate or 2-pinnate-pinnatisect 7
-92-
The Spleenworts and their relatives (continued) 39-48
3 Leaves forked or with 2 or 3 clustered pinnae
septentrionale (47)
3 Leaves pinnatisect or pinnate with at least 8 ± equal pairs of
pinnae 4
4 Leaf segments adnate to rachis, densely scaly beneath
ceterach (48)
4 Pinnae petiolate, orbicular to oblong, glabrous or not obviously
scaly beneath 5
5 Pinnae rhomboid-oblong, over 15 mm long marinum (43)
5 Pinnae round-oblong, up to 11 mm long 6
6 Rachis green throughout length of leaf
[ trichomanes-ramosum (45)
i 6 Rachis black- or red-brown (except at leaf apex)
trichomanes (44)
7 Pinnae irregularly cut into ± equal segments
ruta-muraria (46)
7 Pinnae regularly pinnate, segments decreasing to pinnatisect
apex 8
^ 8 Leaf-blade and pinnae triangular to triangular-ovate 9
8 Leaf-blade and pinnae linear-lanceolate to lanceolate
obovatum subsp. lanceolatum (42)
9 Apex of leaves, pinnae and ultimate segments caudate
onopteris (41)
9 Apex of leaves, pinnae and ultimate segments blunt or
rounded adiantum-nigrum (40)
Hybrids
For a list of, and notes on, hybrid spleenworts, see p. 118.
-93-
39 Hart’s Tongue
Asplenium scolopendrium L.
LEAVES up to 75 cm (or
rarely to 1 m), undivided.
LEAF-BLADE
lanceolate or linear-
lanceolate, (young plants
ovate, broadly lanceolate or
hastate) base cordate, lobed
or auriculate, apex acute or
occasionally obtuse; margin
wavy, irregularly crenate or
occasionally irregularly cut
(especially when growing on
damp walls).
STIPE 1/6 - 1/3 of leaf length,
of a dark purple-black
colour which persists well up
the rachis, scaly below.
SCALES c. 8 mm long,
linear-triangular, pale
brown.
HABIT: Rhizome, short, stocky and erect, branching to form many
close crowns; leaves forming an irregular cluster; wintergreen;
young croziers very pale, almost translucent green.
-94-
Hart’s Tongue (continued)
39
SORI linear, lying in close pairs
along ± parallel, adjacent veins,
± median position between ractiis
and margin, throughout the whole
length of the leaf.
INDUSIA linear, membranous, those
of a pair opening towards each other.
HABITAT: A plant of base-rich habitats, on limestone, basalt,
andesite and other base-rich substrates, or where salt-laden winds
replenish soils with magnesium, and in such situations found
amongst shady scrub in sand-dune slacks and on Cornish lane banks
on granite; in damp gullies and gorges in mountainous districts but
rarely above 200 m (666 ft); a dominant fern in ash woods on
limestone.
DISTRIBUTION: Common throughout England and Wales, and in
Ireland; in Scotland its distribution is governed by altitude and lack
of suitable substrates.
CONSERVATION STATUS: Not threatened in any way.
COMPARE WITH:
This fern can be confused with no other.
A. scolopendrium is a species with a range of variation of shape and margin
characteristics which has given rise to many cultivars, many of which were (and
might still be) found in the wild; most are sterile and can only be propagated
vegetatively.
-95-
40 Black Spleenwort
Asplenium adiantum-nigrum L.
LEAVES 10-25 cm long in
more exposed sites, up to
50 cm when in sheltered
woodland.
LEAF-BLADE triangular
or triangular-ovate,
2-3-pinnate or 2-pinnate-
pinnatisect, shiny, deep
mid-green.
PINNAE up to 15 pairs,
the lowest pair the
longest, up to 10 cm long,
decreasing in size to the
pinnatisect leaf apex;
± triangular-ovate to
broadly trowel-shaped.
NOTE: The shape of both
pinnae and ultimate
segments very variable, as
shown in the sample of leaf
silhouettes, and some forms
are very difficult to
distinguish from (41) and
the Continental
A. cuneifolium (see below).
STIPE black to red-brown,
shiny, glabrous.
SCALES on rhizome
growing point narrowly
triangular-lanceolate with
darker, more opaque cells in
centre.
HABIT: A very variable plant with leaves in a loose tuft from a
short-creeping rhizome; wintergreen.
-96-
Black Spleenwort (continued)
40
ULTIMATE
SEGMENTS ovate-
elliptic to oblanceolate,
often deeply and sharply
toothed.
SORUS 1-3 mm, linear-
oblong, on lateral veins
and appearing closer to
the midrib than to the
segment margin.
INDUSIUM linear-oblong,
entire.
EXOSPORE length
30-37 yLtm (x400).
HABITAT: Requires a trace of base-rich elements and rarely found
on acid rock; a plant of rocky places, cliffs, screes, hedgebanks
(particularly in SW England), and climax woodland established over
calcareous rock scree; generally an uncommon component of
mortared wall floras, and in areas of low rainfall only on walls
exposed to prevailing winds; rarely above 600 m (2000 ft).
DISTRIBUTION: Throughout the British Isles; commoner in
coastal £u-eas of the west, absent from some areas in Central and
Highland Scotland and the colder rain-shadow east of the Pennines.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(41) A. onopteris, which has more caudate tips to the
pinnae and leaf apex, and smaller spores;
(42) A. obovatum subsp. lanceolatum which has a
lanceolate leaf-blade, narrower, more oblong pinnae, and
sori nearer the margin.
Asplenium cuneifolium Viv., a diploid species with flabellate ultimate
segments with obtuse teeth, known from ultrabasic rock in mainland
Europe, has been recorded from the British Isles in error; all such plants
have been confirmed as tetraploids and must be regarded as a form of
A. adiantum-nignitn. The diploid may, however, occur on serpentine rocks
in our area.
-97-
41 Acute-leaved Spleenwort
Asplenium onopteris L.
LEAVES 15-25 cm long,
sometimes longer when in
sheltered sites.
LEAF-BLADE triangular,
3-pinnate or
3-pinnate-pinnatisect,
tapering to a caudate apex,
very shiny above, mid-green.
PINNAE triangular or
triangular-ovate, up to
12 cm long, the lowest
pinnae the longest,
decreasing in size to a
pinnatisect caudate apex.
NOTE: As with (40) there is
considerable variation in the
shape of pinnae and ultimate
segments in Continental
material, sometimes
appearing very similar to
(40), although Irish material
is ± constant and more like
the Iberian plants.
STIPE black to red-brown,
shiny, glabrous; coloration
extending well into rachis.
SCALES narrowly
triangular-lanceolate with
darker, more opaque cells in
centre.
HABIT; A plant with a short-creeping rhizome with evergreen
leaves in a loose tuft.
-98-
Acute-leaved Spleenwort (continued)
41
ULTIMATE
SEGMENTS narrowly
lanceolate with an acute
apex.
SORUS 1-2 mm long,
oblong, on lateral veins
and closer to the midrib
than the segment margin.
INDUSIUM Unear-oblong,
entire.
EXOSPORE length
25-30 /am, (x 400).
HABITAT: Predominantly a lowland, terrestrial plant on banks
under light shade or on old scree colonised by scrub; requiring a
modicum of base-rich elements; occasionally found on rock in
maritime situations.
DISTRIBUTION: A Mediterranean species known only in the
British Isles from SW Ireland. Records for the Lizard peninsula
and Shropshire are in error, the plants being finely dissected
forms of (40).
CONSERVATION STATUS: A rare plant which could possibly be
lost through being shaded out or by afforestation.
COMPARE WITH;
(40) A. adiantum-nigrum which for the most part lacks
the finely drawn out (caudate) tips to the pinnae and
leaf apex and is somewhat thicker and more rigid. The
size of the spores is a helpful check, but 30 should be
measured;
(40 X 41) A. X ticinense is difficult to distinguish but will
have abortive spores; it will only be found with the
parents.
-99-
42 Lanceolate Spleenwort
Asplenium obovatum Viv.
subsp. lanceolatum P. Silva
LEAVES 10-30 cm long.
LEAF-BLADE
lanceolate, 2-pinnate,
shiny, deep mid-green.
PINNAE up to 20 pairs, up
to 4 cm long, (the lowest
pair shorter than the one
above it), linear-
lanceolate to oblong,
pinnate below, pinnatisect
above, apex ± blunt.
STIPE c. 1/3 - 1/2 length of
leaf (longer if plant in a
crevice), dark red-brown,
shiny, glabrous, persistent
and becoming paler when
leaf dies.
SCALES on stipe base and
rhizome growing point
narrowly triangular-
lanceolate, purple-brown
metallic lustre.
HABIT: A plant with a short-creeping, often much-branched
rhizome, giving rise to a compact tuft of old stipes and leaves which
are initially herbaceous but later ± leathery and persistent; in
exposed situations bent back onto the rock surface; wintergreen.
- 100-
Lanceolate Spleenwort {continued)
42
ULTIMATE SEGMENTS up to 10
pairs, 4-10 mm long, ovate or
obovate to almost orbicular, base
cuneate and narrowed into a
petiole, dentate towards the apex
with mucronate teeth; often
deflexed backwards from
the plane of the pinnae.
SORUS 1-2 mm, linear-
oblong, on lateral veins
and appearing closer to
the margin than the
segment midrib.
EXOSPORE length
33-38 ixm (x 400).
HABITAT: Predominantly a maritime plant normally found on
base-poor rocks or soils over grits and igneous rocks, exposed to
salt-laden winds which must provide the required salts. Rarely on
inland drystone walls exposed to prevailing winds. Occasionally
found in the Channel Isles on hedgebanks, with (40).
DISTRIBUTION: The Channel Isles and the SW peninsula as far
east as Portland Bill; through maritime Wales and Snowdonia,
isolated sites in Cumbria, IGntyre, W Sutherland and in S Ireland.
CONSERVATION STATUS: Coastal sites not vulnerable; lost
from some inlcmd sites possibly by herbicide spraying. Protected in
the Republic of Ireland under the Flora (Protection) Order, 1980.
COMPARE WITH:
(40) A. adiantum-nigrum for which, see that species.
A. obovatum subsp. obovatum has not been found in the British Isles,
but might reach the Channel Isles and our southern shores. It has shorter,
more ovate pinnae with fewer pinnules; its spore size (28-32 jum) can
confirm its identification. Young sterile plants of (42) can be very similar,
but the guard-cell length will be 41-50 /xm not 53-64 /u.m.
-101-
43 Sea Spleenwort
Asplenium marinum L.
LEAVES up to 20 cm
(sometimes longer if in a
sheltered crevice).
LEAF-BLADE
RACHIS green,
narrowly winged.
STIPE shiny, purplish
brown.
SCALES narrowly
triangular, lustrous,
purple-grey.
lanceolate, 1-pinnate,
tapered to a pinnatifid
± acute apex, bright
mid-green, glossy above,
matt and paler beneath,
rigid, fleshy.
PINNAE up to 3 cm
long, rhomboid-
oblong, base cuneate,
apex rounded, well
Spaced or sometimes
crowded and ±
overlapping, margin
crenate;
lowest pinnae
sometimes lobed.
HABIT: A tufted plant, leaves arising from a short, ascending
rhizome, usually appressed to the rock surface; wintergreen.
- 102-
Sea Spleenwort {continued)
43
SORUS linear-oblong.
INDUSIUM with entire
margin, persistent.
HABITAT: A species tolerant of being regularly washed with salt
spray, and found on vertical cliffs and ledges of various hard rocks on
often very exposed shores, associated with Sea Plantain and
maritime lichens. Obviously not dependent on salt as found inland,
albeit very rarely, usually on calcium/magnesium-bearing rocks.
Very sensitive to frost and absent from colder eastern coasts.
DISTRIBUTION: Around the coast of Britain from the Isle of
Wight westwards, becoming less common on the east coast of
Britain and no further south than Scarborough, Yorks; around the
Irish coast but less common on the east. Rare inland populations
occur in Derbyshire and Fermanagh.
CONSERVATION STATUS: In no way endangered.
COMPARE WITH:
A morphologically distinctive fern amongst all European
Asplenium species although the following (albeit very
rare) hybrid does show some similarities:
(42 X 39) A. X microdon may have similar cutting in the
lower part of the leaf, but the wide scolopendrium-hke
apex and thinner texture is distinct.
-103-
44a Delicate Maidenhair Spleenwort
Asplenium trichomanes L.
subsp. trichomanes
A complex of plants which show considerable variation
depending on whether they are growing in exposed or
sheltered conditions. Three subspecies have been
recorded from Britain and although they can only be
identified with certainty by their spore or stomata sizes
or chromosome number, we have given significant
characteristics in bold below.
LEAVES up to 20 cm long.
LEAF-BLADE linear to elliptical or narrowly
lanceolate, 1-pinnate, tapered, sometimes abruptly, to a
toothed or lobed terminal leaflet, thin and herbaceous
in texture, mid-green.
RACHIS black-brown,
becoming red-brown (except
at the very apex which is
green), with a very narrow
longitudinal wing running
down either side.
STIPE glossy, at first black-
brown, rapidly becoming
thin, wiry, bronze-red-
brown, persistent long
after the pinnae have
been shed.
Longest SCALES 3.5 mm
with a central red-brown
stripe (best seen in liquid
medium).
HABIT: An often densely tufted plant, with the leaves more
usually arching away from the substrate; remaining green
throughout the winter and often for 2-3 years, the pinnae
eventually dropping leaving what soon becomes a dense tuft of
persistent stipes and rachises with the new leaves emerging
through the mass.
- 104-
Delicate Maidenhair Spleenwort (continued)
44a
PINNAE up to 8 mm
long, orbicular (in
exposed sites) to oval or
rhombic and asymmetric
(in more sheltered sites),
with a distinct stalk,
more widely spaced than
(44b), mostly alternate,
those in the upper part
obliquely inserted,
distinctly longitudinally
ridged, often curling
under along the wavy
margin whilst turning up
at the apex.
SORUS up to 2 mm long,
4-6 per pinna.
EXOSPORE length
28-32 Atm (x400).
INDUSIUM narrow
and delicate.
STOMATA: mean guard-
cell length 32-40 /ttm
(x 400).
HABITAT: A definite calcifuge on acid Ti.e. silicious) rock faces in
crevices and narrow ledges, diystone walls where completely free of
mortar, and on well-dramed shaded banks by roads, trackways and
streams; from sea-level to c. 800 m (2500 ft.).
DISTRIBUTION: Restricted to acid rock areas of Wales, the Lake
District and Scotland; recorded only in Co. Down in Ireland.
Under-recorded due to difficulty of identification.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(44b) A. trichomanes subsp. quadrivalens.
M4c) A. trichomanes subsp. pachyrachis.
Both these subspecies have larger spores and stomata,
but see under (44c) for a further diploid taxon with
small spores wnich may occur in Britain.
-105-
44b Common Maidenhair Spleenwort
Asplenium trichomanes L.
subsp. quadrivalens D.E. Meyer emend. Lovis
LEAVES up to 20 cm long.
LEAF-BLADE linear to elliptical or narrowly
lanceolate in outline, 1-pinnate, tapered,
sometimes abruptly, to a toothed or lobed terminal
leaflet, thin and herbaceous in texture, mid-green.
RACHIS black-brown (except at the very apex
which is green), with a very narrow longitudinal
wing running down either side.
STIPE thick, glossy, black-brown or dark
brown and remaining so throughout the
season, eventually becoming dull, often
persistent but less so than in (46a), the dead
leaf tending to break off just above stipe
base.
r.
% 4
Longest SCALES 5 mm with a central dark
brown stripe (best seen in liquid medium).
HABIT: A less densely tufted plant than (46a), with the leaves
usually appressed to the substrate in a sinuous manner
when in more exposed situations and in rock crevices;
remaining green throughout the winter as in (46a), but the
pinnae more often remaining attached until the leaf dies
and breaks away.
-106-
Common Maidenhair Spleenwort (continued) 44b
EXOSPORE length
32-38 /Ltm (x 400).
PINNAE up to 11 mm
long, more crowded than
in (44a) (but spread in
shady situations), oblong
(even in exposed sites),
symmetrical, almost
sessile, mostly opposite
with a square insertion,
lacking longitudinal
ridges, the lateral
margins tending to roll
under but the apex flat.
SORUS up to 3 mm long,
4-9 (-12) per pinna.
INDUSIUM broad,
conspicuous and more
persistent than (44a).
STOMATA: mean guard-
cell length 40-48 /xm
(x 400).
HABITAT: A calcicole, on limestone, basalt and many other rock
types which may have only very low calcium content; in crevices and
on narrow ledges, mortared walls, especially those facing SW, and
on well-drained rocky banks and stream valleys; from sea-level to
c. 800 m (2500 ft).
DISTRIBUTION: Throughout the British Isles, but less frequent in
Ireland.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(44a) A. trichomanes subsp. trichomanes which is a
calcifuge and has smaller spores;
(44c) A. trichomanes subsp. pachyrachis which is so far
known only from limestone rocks and has a scalloped
margin to the pinnae.
-107-
44c Lobed Maidenhair Spleenwort
Asplenium trichomanes L.
pachyrachis (Christ) Lovis & Reichst.
LEAVES up to 12 cm long.
LEAF-BLADE elliptical or narrowly lanceolate,
1-pinnate, tapered, sometimes abruptly, to a
toothed or lobed, slender triangular terminal
leaflet, thin and herbaceous in texture, mid-green.
RACHIS dark black-brown, glossy, with a very
narrow longitudinal wing running down either side.
STIPE thick, glossy, black-brown or dark
brown and remaining so throughout the
season, eventually becoming dull, often persistent
but less so than in (46a), the dead leaf tending to
break off just above stipe base.
Longest SCALES 5 mm with a central dark
brown stripe (best seen in liquid medium).
HABIT: An open-tufted plant with the leaves often appressed to
the substrate, many showing a characteristic sinuous curve;
remaining green throughout the winter and usually not dropping
the pinnae, as in subsp. trichomanes (44a).
- 108-
Lobed Maidenhair Spleenwort (continued)
44c
SORUS up to 3 mm long,
4-9 (-12) per pinna.
EXOSPORE length
32-38 fjLm (x 400).
PINNAE up to 11 mm long,
often ± overlapping (but more
separated in shady situations),
oblong (even in exposed sites)
to subtriangular or even
hastate, usually with a
distinct auricle on the
acroscopic margin,
symmetrical, almost sessile or
sometimes shortly stalked,
opposite or alternate above,
alternate below, with a square
insertion, margin often
deeply crenately toothed
and wavy.
INDUSIUM broad,
conspicuous and more
persistent than (44b).
STOMATA: mean guard-
cell length 40-49 fim
(x 400).
HABITAT: On limestone and then usually on more vertical faces
and in crevices on steeper rocks; on mortared walls, especially old
castles; to c. 230 m (750 ft).
DISTRIBUTION: Recently found in Herefordshire,
Gloucestershire, Gwent, with old records also from Merioneth,
Yorkshire and Co. Clare.
CONSERVATION STATUS: Over-zealous owners/managers of
ancient monuments may remove plants in cleaning operations;
the more attractive forms are vulnerable to collection.
COMPARE WITH:
(44b) A. trichomanes subsp. quadrivalens which is also a
calcicole and has spores of a similar size; pinna margin
and shape is distinctive;
(45) A. trichomanes-ramosum in which the leaves are
more upright and have green rachises.
A. trichomanes subsp. inexpectans Lovis from limestone in S Europe is a
very similar plant with often glaucous leaves and a large terminal pinna, but
is diploid with smaller spores (27-31 fxm)-, it could be present in Britain.
-109-
45 Green Spleenwort
Asplenium trichomanes-ramosum L.
LEAVES up to 18 cm long.
LEAF-BLADE linear, narrowly elliptical or
lanceolate, 1-pirmate, tapered gradu^ly (or
sometimes abruptly) to a toothed or lobed
terminal leaflet, somewhat tapered towards the
base, lower pinnae well-spaced; thin and
herbaceous in texture, pale to apple-green.
RACHIS green, without a wing.
STIPE dull, green, l/6 - 1/4 leaf length, dark
chestnut-brown at the extreme base and this part
only persistent on leaf-fail.
Longest SCALES 5 mm with a central dark brown
stripe (best seen in liquid medium).
HABIT: A tufted plant with the leaves standing erect or
becoming pendulous on vertical rock-faces from a short
branched rhizome, old plants forming large clumps; tending to
die down in the winter except in very clement areas.
- 110-
Green Spleenwort (continued)
45
PINNAE up to 7 mm
long, oblong-ovate, those
near the leaf base
symmetrical, those above
less so, shortly stalked,
mostly alternate, with a
square insertion,
distinctly toothed or
crenately lobed at the
margin.
SORUS up to 2 mm long,
2-6 per pinna.
INDUSIUM broad,
conspicuous, persistent.
HABITAT: A calcicole, on limestone, basalt, schists and many
other rock types which may have only very low calcium content; on
rock-faces, in crevices and on ledges, in grykes of limestone
pavement, rarely on mortared walls; in zdl cases associated with high
rainfall, water spray or run-off; mainly in mountains to c. 1000 m
(3300 ft).
DISTRIBUTION: In Britain only north of the Severn-Wash line;
confined in Ireland to a few high areas with a low mean summer
temperature.
CONSERVATION STATUS: Not threatened in Britain, but
vulnerable to quarrying in Ireland.
COMPARE WITH:
(44b, 44c) A. trichomanes subspp. quadrivalens and
pachyrachis, both of which have dark rachises.
A. adidterinum Milde, a species confined to serpentine in Scandinavia and
Central Europe is the fertile result of hybridisation between the above and
A. trichomanes subsp. trichomanes and therefore intermediate in
morphology, could exist on serpentine in Britain. It has a purple-brown
rachis in the lower half and green above.
- Ill-
46 Wall Rue
Asplenium ruta-muraria L.
LEAVES up to 8 cm long.
LEAF-BLADE trifoliate in the smallest
leaves, to 2- or 3-pinnate, somewhat
irregularly dissected in larger leaves,
triangular-ovate.
RACHIS and ultimate segment stalks
green with occasional stalked glands.
STIPE 1/2 - 2/3 leaf length, covered
when young with numerous sessile or
shortly stalked glands which are lost on
maturity, green except at extreme base
which is black-brown.
lustrous, bluish-grey.
HABIT: Small tufts of 3 to many erect or ascending leaves arising
from a short-creeping rhizome; wintergreen.
- 112-
Wall Rue {continued)
46
ULTIMATE LEAF
SEGMENTS up to 8mm
long, fan-shaped or
rhomboid, to
oblanceolate or oblong,
thick almost leathery
texture, deep bluish
green above, paler
beneath.
SORUS 1-3 mm long,
2-6 per segment.
INDUSIUM oblong to
narrowly linear.
HABITAT: A calcicole common on limestone and in grykes, but
found also in crevices of rock-faces in exposed situations, and
occasionally on a wide variety of rock types; in maritime areas
calcium and magnesium requirements will be fulfilled by salt-laden
winds; also on man-made walls, especially churches and bridges;
from sea-level to high altitudes of 1000 m (3330 ft).
DISTRIBUTION: Common throughout the British Isles, but
scarcer ciround industrial areas and in the peatlands of
N Scotland.
CONSERVATION STATUS: Not threatened, although sensitive
to atmospheric pollution.
COMPARE WITH:
Not confused with any other British fern although
A. X murbeckii, the hybrid with (47), has been recorded
and can be similar; it has abortive spores.
Two chromosome races (diploid and tetraploid) occur \nA. ruta-muraria
and have been give subspecific rank. The British material is tetraploid
(subsp. ruta-muraria); the diploid subsp. dolomiticum Lovis & Reichst. is
found in central Europe.
- 113-
47 Forked Spleenwort
Asplenium septentrionale (L.) Hoffm.
LEAVES usu2illy 4-8 cm, occasionally up
to 14 cm long.
LEAF-BLADE once or twice forked or
1-pinnate and appearing tripartite, those
on young plants often simple, thick,
somewhat leathery, deep green with a
satin rather than glossy surface.
STIPE 1/2 - 2/3 leaf length, green
becoming purple-brown at the base
SCALES to 5 mm,
lustrous purple-grey.
HABIT: A tufted plant with leaves arising from many crowns on a
short-creeping branched rhizome, often firmly embedded in a rock
crevice; leaves being wintergreen persist for many years and may
form large clumps.
- 114-
Forked Spleenwort {continued)
47
SEGMENTS up to
20 mm long, 2-4 mm wide,
linear-elliptical or wedge-
shaped, drawn to an often
jagged or acute apex, tapered
below to an elongate (to
10 mm) stalk; margin with
occasional, irregular, acute teeth.
SORUS often 3-4 mm long,
appearing linear along segment
although on very acutely inserted
vein.
INDUSIUM linear, entire.
HABITAT: A calcifuge usually on grits and quartzitic sandstones,
and on slates and hard metamorphic rocks totally devoid of calcium
or other base salts; occasionally established on drystone walls; sea
level to 450 m (1500 ft).
DISTRIBUTION: An uncommon species in Britain, frequent on the
Silurian rocks of northern Wales, in the Lake District and
N Enigland, and in isolated localities in Scotland, including Rhum
and the Ardnamurchan Peninsula; a single native locality in Ireland
(W Galway) although introduced in Co. Down.
CONSERVATION STATUS: Not seen in about 40% of recorded
sites in the last 30 years and shading of rock-faces by
afforestation may be a threat; otherwise the habitat is not
vulnerable. Protected in the Republic of Ireland under the Flora
(Protection) Order, 1980.
COMPARE WITH:
There is no other similar species in the British Isles, but
two hybrids with this species (both of which have abortive
spores) have obvious similarities:
(40 X 47) A. X contrei has a broader leaf outline, with the
two lower pinnae pinnately divided;
(47 X 44a) A. x altemifolium has a regularly pinnate,
lanceolate or narrowly triangular leaf.
-115-
48 Rustyback
Asplenium ceterach L.
LEAVES up to 18 cm long,
densely covered beneath
on both lamina and
midrib with scales which
are colourless on
unfurling leaves,
becoming pale reddish
brown on maturity.
LEAF-BLADE elliptic to
oblanceolate, pinnatisect;
segments toweirds apex
becoming contiguous and
merging into a lobed apex,
those at the base widely
spaced, alternate and
forming a zig-zag
pattern.
STIPE c. 1/4 leaf length,
densely covered with pale
red-brown scales.
SCALES up to 3 mm long,
ovate to broadly lanceolate,
acuminate at tip, pale
reddish brown.
HABIT: A densely tufted plant of several crowns arising from a
very short-creeping or ascending rhizome, with many wintergreen
leaves. In times of seasonal drought leaves become desiccated and
curl inwards exposing the scale-covered underside; when moistened
they continue normal growth and activity, and may even develop a
second crop of sori amongst the old ones.
- 116-
Rustyback (continued)
48
LEAF SEGMENTS 8-16 mm long, 4-10 mm wide, oblong, those
at the base of the leaf shorter and almost spherical, apex rounded,
covered beneath with appressed, overlapping pale red-
brown scales, those at the edge standing out as a fringe,
upper suiface glabrous, dull bluish-
green, mztrgin entire or crenate.
SORUS and INDUSIUM linear-
oblong covered by the
overlapping scales.
HABITAT; A calcicole, common on limestone rocks of all
dispositions and on mortared walls, in areas of high rainfall or on
walls that face the prevailing winds, in spite of its ability to
withstand drought. Lowland to c. 200 m (600 ft) altitude, zdthough
occasionally higher; a species of southern Atlantic affinities.
DISTRIBUTION: In SW England and Wales and the Lake District,
scattered in the Pennines £md SW Scotland but very rare north of
the Grampian Highlands and east of the Pennines m England;
common throughout Ireland except in northern counties.
CONSERVATION STATUS: Not threatened in its native habitats
but vulnerable to rebuilding etc. of man-made substrates at the edge
of its range.
COMPARE WITH:
A distinct species not confused with any other in the
British flora.
- 117-
39-48 Hybrid Spleenworts
The following spleenwort hybrids have been found in the
British Isles:
A. X akenufoUum Wulfen
= (47) A. septentrionale x (44a) A. trichomanes
subsp. trichomanes
A. X clermontae Syme
= (46) A. ruta-muraria x (44b) A. trichomanes
subsp. quadrivalens
A. X confluens (T. Moore ex Lx)we) Lawalr6e
= (39) A. scolopendrium x (44b) A. trichomanes
subsp. quadrivalens
A. X contrei Call6, Lovis & Reichst.
= (40) A. adiantum-nigrum x (47) A. septentrionale
A. X jacksonii (Alston) Lawalrde
= (40) A. adiantum-nigrum x (39) A. scolopendrium
A. X rmcrodon (T. Moore) Lovis & Vida
= (42) A. obovatum ssp. lanceolatum x
(39) A. scolopendrium
A. X rruubecku Dorfler
= (46) A. ruta-muraria x (47) A. septentrionale
A. X samiense Sleep
= (40) A. adiantum-nigrum x (42) A. obovatum
subsp. lanceolatum
A. X ticinense D, E. Meyer
= (40) A. adiantum-nigrum x (41) A. onopteris
A. trichomanes nothossp. bisaticum (D.E. Meyer)
Lawalrde
= (44a) A. trichomanes subsp. trichomanes x
(44b) A. trichomanes subsp. quadrivalens
A. trichomanes nothossp. staufferi Lovis & Reichst.
= (44b) y4. trichomanes pachyrachis x
(44c) A. trichomanes subsp. quadrivalens
All the hybrids listed above are rare and several have been found
only once. They are all intermediate in morphology between their
parents and can be confirmed by their abortive, shrivelled spores.
-118-
Hybrid Spleenworts {continued)
39-48
A. X altemifolium occurs in several counties in N Wales,
Cumbria and southern Scotland where the parents grow together
but at no site is it frequent nor as well established as this hybrid cj\n
be in mainland Europe. It is likely that some hybrids between the
commoner species (e.g. A. x jacksonii, A. x samiense) may be more
frequent than records suggest. The former is quite distinctive in its
morphology, but the latter can be very similar to the variable
A. adiantum-niffum.
SCO
I hybrids recorded in the British Isles
4 hybrids recorded in continental Europe that may be found in
the British Isles
- 119-
49 Lady Fern
Athyrium filix-femina (L.) Roth
LEAVES up to 120 cm;
a very variable plant in its
leaf cutting and texture
which has produced a
number of attractive
cultivars.
LEAF-BLADE
elliptic-lanceolate, tapered
somewhat abruptly to an
acuminate apex, 2- or
3-pinnate; dull, mid- to
somewhat blue-green.
PINNAE linear-lanceolate,
tapered to a fine apex,
truncate below, the lowest
pinnules touching the rachis,
alternate and contiguous
above, decrescent and
± opposite and remote
below.
RACHIS green, or
purplish red, a character
which appears to breed true
but has no taxonomic
significance, scaly towards
base.
STIPE 1/4 - 1/2 leaf length,
coloured as rachis, densely
scaly at base.
SCALES to 10 mm,
triangular-lanceolate, entire,
dark brown to pale straw-
coloured.
HABIT; Leaves arising from an erect rhizome forming a dense
‘shuttlecock’; dying down with the earliest frosts.
- 120-
Lady Fern {continued)
PINNULE length often very
variable along pinna, linear-
lanceolate, apex obtuse to
acute, pinnatisect, or in
some forms pinnate-
pinnatifid.
SORUS oblong to linear,
close to vein, those on
larger pinnules often
J-shaped, straddling the
vein.
INDUSIUM linear,
oblong or J-shaped,
membranous (x 10).
SPORES minutely
scabrid (x 400).
HABITAT: A plant that likes to have its roots in moving water and
thus found near streams and in wet hollows in shady woods, and on
hillsides and in ‘lazy-bed’ channels in the open in W Scotland and
areas of higher rainfall.
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(50) A. distentifolium, which has a flatter, more yellow-
green leaf, and lacks an indusium;
pS) Oreopteris limbosperma, the leaf of which is
^andular, lemon-scented, less cut and has many
decrescent pinnae down the length of the stipe; its sori
are marginal and lack obvious indusia.
- 121-
50a Alpine Lady Fern
Athyrium distentifolium Tausch ex Opiz
var. distentifolium
LEAVES up to 75 cm.
LEAF-BLADE elliptic-
lanceolate, tapered to an
acuminate apex, 2- or almost
3-pinnate, pale to
yellowish green, the
margins of the ultimate
segments touching giving
a less lacy appearance
than in (49).
PINNAE linear-lanceolate,
tapered to a fine apex,
truncate below, the lowest
pinnules touching the rachis,
alternate and contiguous
above, decrescent and
± opposite and remote
below.
RACHIS pale yellow-
green, almost
translucent, scaly
towards base.
STIPE c. 1/4 length of leaf,
coloured as rachis becoming
pinkish or straw-coloured at
base, usually densely scaly.
SCALES to 10 mm
triangular-lanceolate, entire,
pale straw to buff.
HABIT: Leaves arising in dense ‘shuttlecocks’ from an erect,
branched rhizome forming often large clumps of many crowns;
turning brown and dying down in winter but possibly more
resistant to frost than A. filix-femina.
- 122-
Alpine Lady Fern (continued)
50a
PINNULE length
± uniform, linear-
lanceolate, apex obtuse to
acute, pinnatisect.
SORUS ± round and
appearing more
uniformly arranged on
the pinnule than in
(50b).
INDUSIUM imperfectly
formed or absent,
occasionally seen on very
young leaves as a
rudimentary scale and
soon lost.
SPORE wall with fine
ridges (x 400).
HABITAT: An alpine plant, occurring between 550-1100 m (1800-
3600 ft) on the more acid range of rock types, in gullies, on ledges
and block screes and especially in N-facing corries where snow lies
late into the season, or where spring melt-water percolates.
DISTRIBUTION: Scotland only, on isolated mountains in the NW
and in the W-Central Highlands, but becoming rare in the eastern
Grampians.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(49) A. filix-femina, which has fewer crowns, a more
finely-cut and darker, blue-green leaf, linear or J-shaped
sori with an indusium, and minutely scabrid spores;
(38) Oreopteris limbosperma, the leaf of which is
^andular, lemon-scented, less cut and has many
decrescent pinnae down the length of the stipe; its sori
are marginal and almost contiguous.
- 123-
50b Flexile Alpine Lady Fern
Athyrium distentifolium Tausch ex Opiz
\2iV. flexile (Newman) Jermy
LEAVES up to 35 cm.
LEAF-BLADE ± elliptic,
tapered gradually to an
acute apex, 2-pinnate,
pale to yellowish-green.
PINNAE linear-
lanceolate to
sub-triangular, abruptly
tapered to a subacute or
obtuse apex, alternate,
well-spaced throughout,
lower pinnae often
deflexed, not markedly
decrescent.
RACHIS yellow-green or
reddish, scaly towards base.
STIPE c. 1/5 or less
length of leaf, coloured
as rachis, markedly
deflexed just below the
blade, usually densely scaly.
SCALES to 10 mm,
triangular-lanceolate, entire,
pale straw to golden.
HABIT: Leaves arising in loose, often flattened, ‘shuttlecocks’
from an erect, branched rhizome; dying down in winter. The
deflexed habit of this variety has lead to much speculation as to
the role of the environment in determining leaf form. However,
plants brought into cultivation have retained their morphology
which suggests that the difference is genetical. Nevertheless, we
feel the difference does not merit more than varietal status.
- 124-
Flexile Alpine Lady Fern (continued)
50b
PINNULE length
± uniform, ovate-oblong,
widely spaced, pinnatifid
or coarsely toothed, apex
obtuse, often tridentate.
SORUS ± round, often with
fewer sporangia and less
uniformly arranged on the
pinnule than (50a); sori
frequently in the lower 1/2 of
the leaf only.
INDUSIUM as in (50a).
SPORES as in (50a).
HABITAT: An alpine plant, only occurring above 900 m (3000 ft)
on similar acid rocks as in (50a), in gullies, on ledges and oetween
blocks in screes, especially m N-facing corries.
DISTRIBUTION: Scotland only, on isolated mountains in the NW
and W-Central Highlands.
CONSERVATION STATUS: Habitat not threatened, but the
variety is rare and should not be collected.
COMPARE WITH;
(50a) A. distentifolium var. distentifolium for which see
that variety;
(49) A. filix-femina which can have a similar stature and
size to this taxon, has a more finely-cut, denser and
darker green leaf, and linear or J-shaped sori with an
indusium;
(38) Oreopteris limbosperma, the leaf of which is
^andular, lemon-scented and less cut, and the indusia
are marginal and throughout the leaf.
- 125-
51 Oak Fern
Gymnocarpium dryopteris (L.) Newman
LEAVES up to 40 cm long,
the blade inclined
backwards, almost
horizontal; the fertile leaves
sometimes having slightly
narrower pinnules and
segments, and often longer
stipes.
LEAF-BLADE up to 18 cm
long, 24 cm wide, 2-pinnate-
pinnatisect, broadly
triangular, tripartite, lowest
pinnae pair almost equal in
size and replicas of the
remainder of the blade, rich
mid-green, soft, thin,
dull, glabrous and non-
glandular.
PINNAE linear-lanceolate, apex acute.
RACHIS very slender, brittle, pale green,
glabrous and non-glandular.
STIPE up to 2/3 leaf length, similar to
rachis but with few scales at base.
SCALES colourless on rhizome apex and
unfurling leaves, becoming pale brown
and soon lost from the young leaves.
HABIT: A plant with a wiry, slender, subterranean, much branched
creeping rhizome from which the leaves arise singly to form large
clonal colonies; dying down in late autumn.
- 126-
Oak Fern {continued)
51
PINNULES 5-12 x 3-7 mm,
lobed to pinnatifid, those
towards the base of the
lowest pinnae pinnatisect;
linear-oblong to lanceolate,
apex rounded or obtuse.
SORUS 1-2 mm, round,
nearer the margin of the
segment than the mid-vein,
without an indusium.
HABITAT: In open woodland, lightly shaded ravines, along
mountain streams, on peaty banks amongst heather and other dwarf
shrubs where there is occasional flushing of mineral-rich water;
requires a cool moist climate and a cold winter period.
DISTRIBUTION: Throughout Scotland, upland England and
Wales with a few scattered populations in the south and east; very
rare in Ireland, now only recorded for Antrim.
CONSERVATION STATUS: Threatened on the edge of its range
in lowland England by habitat clearance affecting microclimate or
water regime. Protected in Northern Ireland by the Wildlife (NI)
Order, 1985.
COMPARE WITH:
(52) G. robertianum has a narrower, scarcely tripartite,
^andular leaf of a grey-green colour with a distinctive
smell of apples, even in very young specimens.
- 127-
52 Limestone Oak Fern
Gymnocarpium robertianum (Hoffm.) Newman
PINNAE linear-lanceolate
to narrowly triangular, apex
acute.
RACHIS very slender, brittle, pale olive-
green, slightly swollen at junction with
pinna-rachises, glandular.
STIPE c. 2/3 length of leaf, similar to
rachis but with few scales at base.
SCALES colourless on rhizome apex and
unfurling leaves, becoming pale brown
and soon lost from young leaves.
LEAVES up to 45 cm long, with
erect stipes and the blade inclined
slightly backwards; lacking the
dimorphism seen in (51).
LEAF-BLADE
2-pinnate-pinnatisect,
broadly triangular, up
to 22 cm long, 20 cm
wide, lowest pair of
pinnae well developed
but not equal in size to
the remainder of the
blade, grey-green, with
stalked and sessile
glands giving a mealy
appearance.
HABIT: A plant with a slender, subterranean, branched creeping
rhizome from which the leaves arise singly, occasionally forming
large colonies; dying down in the autumn.
- 128-
Limestone O^k Fern (continued)
52
PINNULES 5-12 x 3-7 mm,
lobed to pinnatifid, those
towards the base of the
lowest pinnae pinnatisect;
linear-oblong to lanceolate,
apex rounded or obtuse.
SORUS 1-2 mm, round,
near the margin of the
segment, almost confluent at
maturity, without an
indusium.
^ V ^
HABITAT: A plant of more open habitats than the last species,
found on limestone pavements, screes, rock ledges and other
rocky habitats including old or dilapidated drystone walls; always
associated with calcium-rich substrates.
DISTRIBUTION: Scattered throughout England and Wales on
chalk and limestone areas, occasionally occurring as an adventive on
walls; in Scotland only in isolated localities in Perth and
W Sutherland; in Ireland only in E Mayo.
CONSERVATION STATUS: Threatened in some areas by
quarrying although recolonisation of old quarries possible.
Protected in Ireland by the Flora (Protection) Order, 1980.
COMPARE WITH:
(51) G. dryopteris has a somewhat broader, distinctly
tripartite, non-glandular, glabrous leaf of a rich mid-
green colour.
- 129-
53 Brittle Bladder Fern
Cystopteris fragilis (L.) Bernh.
LEAVES 10-25 cm (or more
if growing luxuriantly or in
crevices), usually ± erect.
LEAF-BLADE elliptic-
lanceolate, tapering below,
apex acute, 2-pinnate, dull,
mid to deep green; the
degree of leaf dissection
appears to be correlated
with chromosome
numben those plants
with more dissected
leaves are usually
hexaploid.
PINNAE narrowly
triangular to lanceolate,
often widely spaced, more
rarely just touching, ± in the
same plane as the blade.
STIPE very slender,
brittle, pale green, black at
the base 1/3 - 1/2 leaf length.
SCALES very sparse at base
of stipe, c. 1-2 mm long,
lanceolate-triangular,
clathrate, grey-brown.
HABIT: Leaves arising in an open cluster at the ends of a short-
creeping, occasionally branched rhizome; leaves become pale yellow
and fall in the autumn.
- 130-
Brittle Bladder Fern (continued)
53
PINNULES pinnatifid or
pinnatisect; ultimate
segments lobed or bluntly
toothed, teeth usually
rounded or very occasionally
retuse.
SORUS ± round, borne
slightly nearer the margin
th2m the midrib on a
vein that runs into the
segment apex (x 10).
INDUSIUM ovoid or
pear-shaped, attached at
the base, acute or
lacerate at the apex, soon
shrivelling.
SPORE wall spinulose
(seen at x 50, but better
at X 400).
HABITAT; A plant of shady moist crevices, under overhangs, etc.,
where seepage water percolates; most frequent on hmestone and
calcium -bearing rocks, and on mortared brick or stone walls when
in permanent shade.
DISTRIBUTION: Throughout the British Isles, but rare in both SE
England and SE Ireland, usually through lack of suitable habitats.
CONSERVATION STATUS: Not threatened, but lost from 134
squares in Britain and 60 in Ireland over the past 30 years.
COMPARE WITH:
(49, 50) Athyrium species, which, when in the sporeling
stage, can be mistaken for Cystopteris; their lower pinnae
are usually more decrescent and they are less cut;
(54) Cystopteris dickieana which has non-spiny spores
and usually broader leaf segments.
- 131-
54 Dickie’s Bladder Fern
Cystopteris dickieana R. Sim
LEAVES 10-20 cm long,
somewhat arching.
LEAF-BLADE broadly
oblong-lanceolate, tapering
slightly below, apex acute
but not tapered, 2-pinnate,
dull, mid- to bluish-green.
PINNAE c. 1.5-3 cm,
triangular, becoming ovate-
oblong towards apex of
blade; pinnate-pinnatisect,
usually oblique to the
plane of the leaf (as a
Venetian blind).
STIPE very slender,
brittle, pale green, black at
the base, 1/4 - 1/3 leaf length.
SCALES very sparse at base
of stipe, c. 1-2 mm long,
lanceolate-triangular,
clathrate, grey-brown.
HABIT: Leaves arising in an open cluster at the ends of a short-
creeping, occasionally branched rhizome; leaves become pale yellow
and fall in the autumn.
- 132-
Dickie s Bladder Fern (continued)
54
PINNULES pinnatifid or
pinnatisect; idtimate
segments lobed or bluntly
toothed, teeth usually
rounded or very
occasionally retuse.
SORUS as in (53) but
usually on a vein that
runs into a sinus (x 10).
INDUSIUM as in (53).
SPORE wall wrinkled
(rugose) and minutely
yerrucose (x 400).
HABITAT: A calcicole of coves and sea caves where seepage water
percolates and which are washed by salt-bearing winds during
storms.
DISTRIBUTION: Known only from the Kincardine/Aberdeen
coast, from where it was introduced into British gardens in the
1850’s and since widely grown. Surprisingly it rarely escapes into
the wild. Reported also from Perthshire and Arran Isles, Ireland,
last century but never verified.
CONSERVATION STATUS: Protected in Britain under the
Wildlife and Countryside Act, 1981.
COMPARE WITH:
(49) Athyrium filix-femina with which it grows, and
which in the sporeling stage can be mistaken for
Cystopteris, but its lower pinnae are usually more
decrescent and less cut;
(53) Cystopteris fragilis, in which the spores are spiny
and usually the leaf-blade and pinnule segments are
narrower.
Material of this species from montane areas of mainland Europe lacks the
gross leaf morphology of the Kincardine plants and can only be identified
with certainty by the spore sculpturing; such plants could occur in the
British Isles.
-133-
55 Mountain Bladder Fern
Cystopteris montana (Lam.) Desv.
LEAVES 12-25 cm or more.
LEAF-BLADE as wide as
long, triangular or
broadly ovate,
2-4-pinnate-pinnatisect,
rachis often bent back so
that the upper half of the
blade is oblique but with
the pinna-tips curving
upward.
PINNAE triangular to
broadly lanceolate,
assymetrical, those segments
on the basiscopic side
largest, apex acute.
STIPE slender, often 2/3 (or
more) leaf length,
dull green becoming
blackish towards base.
SCALES 1-3 mm, clathrate,
pale brown, fringed with
glands, on the rhizome tip
and scantily on the stipe.
HABIT: Leaves arising singly from a slender (1-2 mm diam.)
much-branched, wide-creeping, dark brown, subterranean rhizome;
the leaf-blades frequently orientated along the same axis; not
wintergreen.
-134-
Mountain Bladder Fern (continued)
55
PINNULE SEGMENTS
very finely cut in fertile
leaves, those of sterile leaves
less so.
SORUS ± round, borne
slightly nearer the mar^n
than the midrib on a vein
that runs into the segment
apex (x 10).
INDUSIUM ovoid or
pear-shaped, attached at
its base, acute or lacerate
at apex, soon shrivelling.
SPORES with low
rounded protuberances
(x 400).
HABITAT; An alpine plant not found below 700 m (2300 ft), on
N-facing ledges, gullies, often unstable and eroded, in sites with a
high calcium content, usually where water is constantly seeping.
DISTRIBUTION; A rare plant found mostly in mica schist areas
of Forfar, Inverness, Perth and Stirling.
CONSERVATION STATUS; At one time under threat from alpine
gardeners; now the most likely threat is from a change to a drier or
warmer climate.
COMPARE WITH:
(51) Gymnocarpium dryopteris, which has a similar
leaf-blade, but is less divided and an intense apple-
green colour; it is also rarely found as high as (55);
(69) Dryopteris expanse, which can sometimes have a
very triangular juvenile leaf and will grow in a similar
habitat; it has a tougher texture, a duller yellow-
green colour and is less dissected.
-135-
56 Oblong Woodsia
Woodsia ilvensis (L.) R. Br.
LEAVES 5-10 (-15) cm
long, often adpressed to
rock face.
LEAF-BLADE oblong-
linear to lanceolate-
triangular, apex ± acute,
pinnate-pinnatisect or
2-pinnate at the base,
± densely covered with
jointed hairs on both
surfaces giving a velvety
appearance to younger
leaves, dark mid-green, dull.
PINNAE up to 15 mm
long, subtriangular to
linear-oblong, apex obtuse
or rounded, barely
contiguous above, often
widely spaced below; pinna-
midrib with narrow
scales.
RACHIS ± densely covered with
scales and hairs, stramineous to a
deeper brown.
STIPE up to 1/3 leaf length, rigid,
jointed c. 1/3 of the way up, brown to
reddish-brown, densely scaly.
SCALES up to 7 mm long, lanceolate-
triangular to linear, pale straw-coloured,
whitish when young.
HABIT: A tufted plant with few crowns from a branched upright
rhizome bearing spreading leaves, often overwintering, eventually
breaking off at an abscission zone (termed ‘joint’ above and a
characteristic of the genus), leaving old stipe bases persistent on the
rhizome.
- 136-
Oblong Woodsia (continued)
56
ULTIMATE SEGMENTS 6-13,
ovate-oblong to orbicular with a
rounded or obtuse apex.
SORI 2-5 round, indusiate.
segment.
often covering
INDUSIUM initially folded
over and partially covering
the sorus, later rolling back,
margin deeply cut into long
narrow projections often
seen as a fringe encircling
the mature sorus.
HABITAT: An arctic- alpine plant of fissures and narrow ledges on
steep or vertical, often E- or S-facing, rock-faces, from 400 m
(1200 ft) altitude upwards; on fine-grained silicious, metamorphic
and volcanic rocks, tolerant of small amounts of calcium.
DISTRIBUTION: Confined to the mountains of N Wales, the Lake
District, the Southern Uplands and in various localities in the
Highlands of Scotland.
CONSERVATION STATUS: With the next species, decimated by
herbarium collectors at the end of the last century such that extant
populations are now so smiill that they may not be viable without
man’s intervention. Protected in Britain under the Wildlife and
Countryside Act, 1981.
COMPARE WITH:
(57) W. alpina has shorter pinnae more closely spaced
towards the leaf apex, with scales on the pinna-midribs.
Young plants of (49, 50) Athyrium species and
(53) Cystopteris fragilis can be confused with sterile
Woodsia, but with magnification the fine scales or hairs
will be seen on the unfurling fronds of the latter. If the
plant is fertile the three genera can be easily
distinguished.
-137-
57 Alpine Woodsia
Woodsia alpina (Bolton) S.F. Gray
LEAVES 2-10 (-15) cm
long, often adpressed to rock
face.
LEAF-BLADE oblong-
linear to oblanceolate, apex
acute, pinnate-pinnatisect,
with sparse, long, jointed
hairs or almost glabrous
on under (abaxial) side,
upper (adaxial) side
glabrous; pale to
mid-green.
PINNAE up to 8 mm
long, subtriangular to
ovate, apex obtuse or
rounded, ± crowded
above, often widely
spaced below; pinna-
midrib never scaly.
RACHIS sparsely
covered with scales and
hairs, stramineous to a
deeper brown.
STIPE 1/5 - 1/4 leaf length, rigid,
jointed c. 1/3 of the way up, brown to
reddish-brown, sparsely scaly.
SCALES up to 5 mm long, lanceolate-
triangular to narrowly linear, pale straw-
coloured, whitish when young.
HABIT: A tufted plant with few crowns forming untidy clusters of
spreading leaves which often overwinter, old fronds eventually
breaking off at an abscission zone (‘joint’) leaving old stipe bases
persistent on the rhizome.
- 138-
Alpine Woodsia (continued)
ULTIMATE SEGMENTS
3-7, obovate-oblong to
orbicular with a rounded or
obtuse apex.
SORI 2-5 towards the
apex of each segment,
round, indusiate.
INDUSIUM initially folded
over and partially covering
the sorus, later rolling back,
margin deeply cut into long
narrow projections often
seen as a fringe encircling
the mature sorus.
HABITAT: An arctic-alpine plemt of fissures and narrow ledges on
steep or vertical, often E- or S-facing, rock-faces, frequently
establishing itself initially in a tuft of moss; on sUicious, metamorphic
and volcamc rocks.
DISTRIBUTION: Confined to the mountains of N Wales and the
Highlands of Scotland from Main Argyll east to Forfar, with an
old record for Skye.
CONSERVATION STATUS: Decimated by herbarium collectors
in the latter half of the last century such that extant populations are
now so small that they may not be viable. Protected in Britain
under the Wildlife and Countryside Act, 1981.
COMPARE WITH:
(56) W. ilvensis has longer pinnae more widely
spaced throughout, scales on the pinna-midribs and
hairs on the upper surface of the leaf segments.
Young plants of (49, 50) Athyrium species and
(53) Cystopteris fragilis can be confused with sterile
Woodsia, but with magnification the fine scales or hairs
will be seen on the unfurling fronds of the latter. If the
plant is fertile the three genera can be easily
distinguished.
-139-
58-60 The Shield Ferns
Dryopteridaceae: Pofystichum
Introduction
Medium to large plants of woods and hedge banks or shady
mountain ledges, gro\\ing singly or in groups.
Cyrtomium falcatum, a close relative from E Asia and often grown
as a houseplant in Europe, is included in this key (see p. 189 for
further details). This genus, which is treated by some as a segregate
of Pofystichum^ has anastomosing veins and sori scattered
irregularly over the wide pinnae.
Characteristics of Polystichum
Stout, erect, scaly rhizome; short, scaly stipes; leaves 1-pinnate-
pinnatisect to 2-pinnate, lanceolate to linear; pinnae and pinnules
unequally divided with largest lobe on apical side; veins free; sori
round, scattered, with thick, centrally attached indusia.
Field key to species
1 Leaves 1-pinnate 2
1 Leaves 1-pinnate-pinnatisect to 2-pinnate 3
2 Pinnae < 1 cm wide, gradually diminishing towards the leaf apex
lonchitis (58)
2 Pinnae > 1cm wide, terminal pinna as large as the lateral ones
Cyrtomium falcatum (A4)
3 Leaves of variable dissection, 1-pinnate-pinnatisect to
2-pinnate, hard texture, lowest pinnae ± 1/2 length of
middle pinnae aculeatum (59)
3 Leaves fully 2-pinnate, soft texture, lowest pinnae ± equal in
length to middle pinnae setiferum (60)
- 140-
The Shield Ferns (continued)
58-60
Hybrid Shield Ferns
The following hybrid shield ferns ( i ) have been found in the
British Isles:
P. X hickneUU (Christ) Hahne
= (59) P. aculeatum x (60) P. setiferum
P. X ilfyricum (Borbas) Hahne
= (59) P. aculeatum x (58) P. lonchitis)
P. X lonchitiforme (Hzdacsy) Bercherer
= (58) P. lonchitis x (60) P. setiferum)
Ion
set
acu
1
1
1
P. X bicknellii is fairly common and may be found wherever the
parents grow close together. It can appear very similar to
P. setiferum, though is often larger and more vigorous, so
confirmation by the presence of abortive spores is essential.
The other two hybrids are very rare and very difficult to distinguish
from each other. P. lonchitiforme, although producing only abortive
spores, is the direct ancestor oiP. aculeatum.
- 141-
58 Holly Fern
Polystichum lonchitis (L.) Roth
LEAVES 12-50 cm long.
LEAF-BLADE narrowly
linear-lanceolate to
linear, 1-pinnate, very
glossy, dark green, feels
tough when stroked.
PINNAE close-set or
overlapping, lowest
pinnae less than 1/2
length of middle pinnae.
STIPE 1/5 - 1/10 leaf
length, very scaly.
HABIT: Leaves forming sparse ‘shuttlecock’ on short, erect
rhizome; wintergreen, often living for several seasons.
- 142-
Holly Fern (continued)
58
PINNA margins with
obvious, stiff spines.
SORI round, usually in a
row either side of the pinna-
midrib.
(x400).
HABITAT: Amongst base-rich rocks and scree in high mountains
(usually above c. 5^ m (1500 ft), occasionally at lower altitudes
near western coasts).
DISTRIBUTION: Rare and local in W Ireland, N Wales,
N Englmd, more common in Scotland.
CONSERVATION STATUS: Protected in N Ireland under the
Wildlife (NI) Order, 1985.
COMPARE WITH:
(59) P. acuieatum, whose juvenile leaves may be
mistaken for this species.
-143-
59 Hard Shield Fern
Polystichum aculeatum (L.) Roth
LEAVES 30-90 cm.
LEAF-BLADE narrowly
lanceolate, variable in
division, 1-pinnate-
pinnatisect to 2-pinnate,
glossy, deep green, feels
stiff when stroked.
PINNAE spaced, not
overlapping, lowest pinna
c i\2 length of middle
pinnae.
STIPE usually less than
i\6 leaf length, very scaly.
HABIT: Leaves forming ‘shuttlecock’ on short, erect rhizome;
wintergreen.
- 144-
Hard Shield Fern (continued)
59
PINNULES (largest)
usually sessile and
decurrent, tapering to very
acute angle at apex, angle
within pinnule base
usually acute.
SORI round, ± along
pinnule midrib.
(x 400).
HABITAT: Mainly upland, in damp, rocky woods and gorges or
mountain scree where base-rich rocks occur.
DISTRIBUTION: Throughout the British Isles, but more frequent
in N England and Scotland.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(60) P. setiferum, which feels soft, has a longer stipe and
the lowest pinnae ± equal in length to the middle ones.
-145-
60 Soft Shield Fern
Polystichum setiferum (Forskal) Woynar
LEAVES up to 1.5 m or
more.
LEAF-BLADE
lanceolate, 2-pinnate,
fairly glossy, bright
green, feels soft when
stroked.
PINNAE well-spaced, not
overlapping, lowest pinna
± equal in length to
middle pinnae.
STIPE usually more than
1/6 leaf length, very scaly.
HABIT: Leaves forming ‘shuttlecock’ on short, erect rhizome;
usually remaining green throughout the winter.
- 146-
Soft Shield Fern {continued)
60
PINNULES (largest)
± stalked, tapering to
obtuse angle at apex, angle
within pinnule base
obtuse.
INDUSIUM thick, round,
attached at centre.
SPORES c. 30 ixm long,
yellow, papillate (x 400).
HABITAT: Mainly lowland (up to c. 250 m, 800 ft), in damp
sheltered hedge banks and river-valley woods on variable soils.
DISTRIBUTION: Throughout most of the British Isles; very
scarce in NE England and Scotland, more frequent in Ireland
and SW England.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(59) P. aculeatum, which feels hard, has a shorter stipe
and lowest pinnae almost 1/2 as long as the middle
pinnae.
- 147-
61-70 The Male and Buckler Ferns
Dryopteridaceae: Dryopteris
Introduction
The British male ferns were originally thought to be just one
species, and were called male in contrast to the equally common,
but daintier, Athyrium filix-femina or lady fern. Dryopteris species
with more divided fronds have been called ‘buckler’ ferns through
the resemblance of the kidney-shaped indusium to the ancient
buckler shield, in contrast to the shield ferns {Polystichum species)
which have a symmetrical, peltate indusium. Species of Dryopteris
are typically associated with woodland, areas which were formerly
woodland and mountain scree.
The evolutionary history of this genus is very complex, and is
not yet fully understood. D. filix-mas (62), D. cristata (66),
D. carthusiana (67) and D. dilatata (68) have evolved by
hybridisation. Only two of the seven diploid ancestors involved,
D. oreades (61) and D. expansa (69), are now found in the British
Isles. Another is so far unknown and the rest are restricted in range
to areas not glaciated during the Pleistocene. A further species,
D. affinis (63), is an apomict (see p. 156) and able to produce self-
perpetuating varieties and microspecies. A detailed treatment of
these is beyond the scope of this book.
Characteristics of Dryopteris
Rhizome apex and stipes covered in scales, sometimes densely
so; leaves typically many and arranged in a ‘shuttlecock’ when the
rhizome is erect, but few if the rhizome creeps, 1-pinnate-
pinnatisect to 2- or 3-pinnate-pinnatifid; sori in a row either side of
midrib of pinna or pinnule segment; indusium kidney-shaped.
Field key to species
1 Leaves 1-pinnate, pinnae pinnatisect 2
1 Leaves 2- or 3-pinnate, at least in lower part of leaf 5
2 Stipe 1/3 or more leaf length, lower pinnae very
broadly triangular, pinnae of fertile leaf held ± at right
angles to the plane of the le£if cristata (66)
2 Stipe 1/3 or less leaf length, pinnae linear to
triangular-linear; pinnae of fertile leaf held ± in the plane
of the leaf 3
- 148-
The Male and Buckler Ferns (continued)
61-70
3 Midrib of pinnae dark at junction with rachis, scales dense
and golden brown affinis (63a-e)
3 Midrib of pinnae not dark at junction with rachis, scales sparse
and pale brown or straw coloured 4
4 Tips of pinnule segments with acute teeth pointing towards
segment apex, margins of indusia initially spreading over
leaf surface and often overlapping each other filix-mas (62)
4 Tips of pinnule segments with obtuse teeth diverging from
segment apex, margins of indusia always well tucked under
and not touching each other oreades (61)
5 Mature leaves very glandular, especially beneath (x 10) 6
5 Mature leaves without glands, young leaves may be sparsely
glandular on midribs and veins (x 10) 7
6 Leaf triangular-ovate in outline, lowest pinnae 3-pinnate, stipe
matt and purplish-brown aemula (64)
6 Leaf triangular-lanceolate in outline, lowest pinnae 2-pinnate,
stipe dull, pale brown submontana (65)
7 Leaf triangular-ovate to triangular, lower part of leaf
3-pinnate 8
7 Leaf linear- or narrowly lanceolate, lower part of leaf
2-pinnate 9
8 Pinnule segments not cut to midrib, edges curving downwards;
stipe c. 1/3 leaf length; leaves blue-green dilatata (68)
8 Pinnule segments cut to midrib, flat, edges not curving
downwards; stipe c. 1/2 leaf length; leaves mid- to pale
green expansa (69)
9 Marins of pinnule segments with very conspicuous, long,
incurving spinulose-tipped teeth that <ue obvious without a
handlens carthusiana (67)
9 Margins of pinnule segments with short spinulose-tipped teeth
that are not striking to the un2iided eye 10
10 Pinnae in the lower 1/3 of the leaf shortly triangular with the
pinna width greater than 1/2 the pinna length cristata (66)
10 Pinnae in the lower 1/3 of the leaf narrowly triangular with
the pinna width much less than 1/2 the pinna length
remota (70)
-149-
61-70 Hybrid Male and Buckler Ferns
The following hybrids ( | ) have been found in the British Isles:
D. \ ambroseae Fraser- Jenkins & Jermy
= (68) D. dilatata x (69) D. expansa
D. X braOuuca Fraser- Jenkins & Reichst.
= (67) D. carthusiana x (62) D. filix-mas
D. X complexa Fraser- Jenkins nothossp. complexa
Fraser- Jenkins
= (63a) D. affinis morph, affinis x (62) D. filix-mas
D. X complexa Fraser-Jenkins nothossp, contorta
Fraser- Jenkins
= (63e) D. affinis morph, cambrensis x (62) D. filix-mas
D. X complexa Fraser-Jenkins nothossp. critica
Fraser-Jenkins
= (63c) D. affinis morph, borreri x (62) D. filix-mas
D. X deweveri (J. Jansen) J. Jansen & Wachter
= (67) D. carthusiana x (68) D. dilatata
D. X mantoniae Fraser-Jenkins & Corley
= (62) D. filix-mas x (61) D. oreades
D. X pseudoabbreviata Jermy
= (64) D. aemula x (61) D. oreades
D. X sarvelae Fraser-Jenkins & Jermy
= (67) D. carthusiana x (69) D. expansa
D. X uliginosa (A. Braun ex Doll) O. Kuntze ex Druce
= (67) D. carthusiana x (66) D. cristata
Some of the hybrids are very rare and have only been found on a
few occasions. They are all intermediate in morphology between
their parents and can be confirmed by their abortive, shrivelled
spores. (NB: Plants of the D. affinis complex have a proportion of
abortive, shrivelled spores as the norm; their hybrids have a higher
proportion of these spores.)
D. X deweveri may be found in some quantity in woods that have
become drier and are no longer a suitable habitat for one parent,
D. carthusiana. This hybrid has a narrower frond outline than the
other parent, D. dilatata^ and the stipe scales have a indistinct, dark,
vertical stripe.
-150-
Hybrid Male and Buckler Ferns (continued)
61-70
ore
-151-
61 Mountain Male Fern
Dryopteris oreades Fomin
LEAVES 40-50 (-80) cm,
ovate-lanceolate, 1-pinnate-
pinnatisect, dull, greyish
mid-green.
PINNAE, especially the
lower ones, curving
forward out of the plane
of the leaf, outline uneven,
triangular below becoming
oblong above.
PINNA MIDRIB without
dark mark on underside
at junction of pinna and
rachis.
LOWEST PAIR OF
PINNAE ± symmetrical or
asymmetrical, innermost
basiscopic segments may be
more developed and stalked
SCALES moderately dense,
± equal width, apex acute
but not hair-pointed, very
pale grey-brown.
STIPE c. 1/4 or less leaf
length, scaly.
HABIT: Plant with erect leaves forming ‘shuttlecock’ on much-
branched, ascending rhizome; dying down in late autumn.
- 152-
Mountain Male Fern {continued)
61
PINNA SEGMENTS
with crisped (turned up)
margins giving a concave
effect, with blunt lobes at
sides, teeth at top broad
and divergent.
SORUS c. 1 mm diam,,
typically only on inner
part of pinnules of top
1/3 of leaf.
INDUSIUM ± thick,
texture granular,
cinnamon coloured at
maturity, margin entire,
usually glandular and
tucked under at first,
maturing to give a
‘mob-cap’ effect.
HABITAT: A mountain plant (c, 240-610 m, 800-2000 ft),
occurring as scattered groups on well-drained ledges or m stands on
well-drained scree slopes; can descend to lower edtitudes on the
colder eastern side of hills or islands.
DISTRIBUTION: Widespread in Scotland, N Britain and Wales;
very rare in Ireland.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) D. filix-mas, which has indusia with flat, spreading
margins, rounded tips to pinnule segments and pinnule
teeth curving towards the apex;
(63) D. afnnis, which has a dark mark at the junction of
pinnae and rachis, and usually dark red or golden
brown scales on stipe and rachis.
-153-
62 Male Fern
Dryopteris filix-mas (L.) Schott
LEAVES c. 35-150 cm,
ovate-lanceolate,
1-pinnate-pinnatisect,
grey-green.
PINNAE held in plane of
leaf, outline ± even, linear-
oblong with a short
acuminate apex.
PINNA MIDRIB without
a dark mark on
underside at junction
with rachis.
LOWEST PAIR OF
PINNAE ± symmetrical or
asymmetrical, innermost
basiscopic segments may be
more developed and stalked.
SCALES moderately dense,
mbrture of broad and
narrow, hair-pointed, pale
brown to straw-coloured.
STIPE 1/4 - 1/3 leaf length,
pale brown, scaly.
HABIT: Plant with leaves forming a ‘shuttlecock’ on short, erect
rhizome; leaves dying early in winter.
- 154-
Male Fern {continued)
62
PINNA SEGMENTS
with flat or slightly
down-curved margins,
toothed at edges, tips
rounded with acute teeth
pointing towards
segment apex, no glands
on either surface.
SORUS c. 1.5 mm diam.,
typically over whole of
pinnules in top 1/3 of leaf.
INDUSIUM thin, margin
entire, initially flattened
and spreading, often
overlapping each other,
shrivelling on maturity
to form a ‘chanterelle’
which is often lost before
the spores are shed.
HABITAT; Lowland woods, hedgerows, gardens, scrub emd
wasteland; in upland to c. 610 m (2000 ft).
DISTRIBUTION: Throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(61) D. oreades, which has spreading teeth at apex of
pinnule segments and the indusium margin tucked
under;
(63) D. affinis, which has a dark mark at the junctions of
pinnae and rachis and the indusium margin tucked under.
-155-
63 Scaly Male Fern
Dryopteris affinis (Lowe) Fraser-Jenkins complex
This ‘species’ shows a range of morphologies of leaf shape, teeth
and lobes of pinna segments, indusium maturation and degrees of
scaliness. The five most commonly seen and easily distinguished
‘morphotypes’ of the span are described on the following pages.
Their ancestry is complicated and thought to involve D. oreades
(61), D. filix-mas (62) and D. affinis morph, affinis (63a). All plants
in the D. affinis complex are apomictic and have some sterile spores
per sporangium (although not as many as in a typical hybrid): each
sporangium produces 32 (rather than the usual ^) spores, with
each spore containing the same number of chromosomes as the
plant producing it (usually the chromosome number is halved);
when the spores germinate, a new sporophyte is produced directly
from the prothallus without the usual fusion of gametes
(anther ozoids and egg cell). Thus they £ue able to produce self-
perpetuating varieties and ‘micro’-species which, although very
limited in distribution, may be locally dominant but almost
impossible to assign to one of the morphotypes described here. To
complicate matters further, sexual reproduction does occasionally
take place and can yield hybrids (see p 150, 151).
No key is given because overall assessment of characters is
necessary to identify a morphotype. Leaf shape (shown opposite),
detail and development (mature stage shown in side view opposite)
of indusia, the teeth and lobes of the pinna segments and degree of
scaliness all need careful evaluation in identifying a specimen.
All morphotypes have indusia with the mzu’gin tucked under to
enclose the developing sporangia in the youngest stages (as in
D. oreades, 61). As the sporangia mature, so do the indusia in ways
characteristic of the different morphotypes. But not all sori, even on
the same pinna segment, develop at the same rate and this is
reflected in the variety of form of the indusia seen on any one pinna
or leaf. Thickness, especially of the margin, and texture are also
important features of the indusium in this group of ferns.
COMPARE WITH:
(61) D. oreades, which lacks a conspicuous dark junction of
the pinna midrib and rachis;
(62) D. filix-mas, which lacks a conspicuous dark junction of
the pinna midrib and rachis, and whose indusia of immature
sori have the margins lying flat on the lamina surface.
- 156-
Scsly NIslc Hern (continued)
-157-
63a Western Scaly Male Fern
Dryopteris ajfinis (Lowe) Fraser- Jenkins
morphotype affinis
LEAVES up to c. 100
(-200) cm, ovate-lanceolate,
base ± tapering, 1-pinnate-
piimatisect, very firm
texture, upper surface of
lamina very glossy.
PINNAE held in plane of
leaf, outline even, oblong
with long acuminate apex
PINNA MIDRIB with dark
mark on underside at
junction of pinna and
rachis.
LOWEST PAIR OF PINNAE
± symmetrical, with the
basiscopic pinna segments
beside stipe partially adnate to
pinna midrib, i.e. not clearly
stalked, and no longer than the
corresponding acroscopic
pinna segments.
SCALES dark gold, very
dense.
STIPE c. 1/6 - 1/5 leaf length.
HABIT; Plant with erect leaves forming a ‘shuttlecock’ on an erect
rhizome; remaining green in part throughout winter.
- 158-
Western Scaly Male Fern {continued)
63a
PINNA SEGMENTS
lying flat in plane of
pinna, margins unlobed
or with shallow lobes.
BASAL LOBE of pinna
segments beside rachis
on lowest few pairs of
pinnae often
insignificant, rounded-
rectangular.
INDUSIUM thick,
remaining well tucked-
under as sporangia
mature, lifting slightly
and occasionally
splitting radially on
maturity, persistent
(mostly still present on
last year’s leaves) (x 10).
HABITAT: Deciduous woods (and along conifer woodland rides),
hedgerows, open hillsides and mountain scree.
DISTRIBUTION: Not completely known; throughout the British
Isles but very rare in some eastern counties.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) D. filix-mas, which lacks a conspicuous dark
junction of the pinna midrib and rachis;
(63b, c, d, e) other morphotypes of D. affinis.
-159-
63b Greater Western Scaly Male Fern
Dryopteris ajfinis (Lowe) Fraser-Jenkins
morphotype paleaceo-lohata (sensu Fraser-Jenkins)
LEAVES up to c. 100
(-200) cm, lanceolate, base
± tapering, 1-pinnate-
pinnatisect, firm texture,
upper surface of lamina
glossy.
PINNAE held out of plane
of frond, outline uneven,
oblong with long
acuminate apex.
PINNA MIDRIB with dark
mark on underside at
junction of pinna and
rachis.
LOWEST PAIR OF
PINNAE asymmetrical,
with the basiscopic pinna
segments beside stipe fully
stalked and usually
slightly larger than the
corresponding acroscopic
pinna segments.
SCALES reddish or very
dark gold.
STIPE c. 1/6 - 1/5 leaf length.
HABIT: Plant with erect leaves forming a ‘shuttlecock’ on an erect
rhizome; remaining green in part throughout winter.
-160-
Greater Western Scnly Mnle Fern (continued) 63b
PINNA SEGMENTS
twisted out of plane of
pinna, margins deeply
lobed and slightly curled
under, apex rounded-
truncate.
BASAL LOBE of pinna
segments beside rachis
on lowest few pairs of
pinnae conspicuous,
round to round-
rectangular.
INDUSIUM similar to
those of (63a), mostly still
present on last year’s
leaves (x 10).
HABITAT: In all types of woodland, hedgerows, open hillsides and
mountain scree.
DISTRIBUTION: Similar to morphotype affinis, absent from the
colder areas in E Britain.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) D. filix-mas, which lacks a conspicuous dark
junction of the pinna midrib and rachis;
(63a, c, d, e) other morphotypes of D. affinis.
-161-
63c Borrer’s Scaly Male Fern
Dryopteris ajfinis (Lowe) Fraser- Jenkins
morphotype borreri (sensu Newman)
LEIAVES up to c. 100
(-200) cm, lanceolate to
oblong, base truncate,
1-pinnate-pinnatisect, texture
not very firm, upper
surface of lamina not
glossy.
PINNAE held in plane of leaf,
outline uneven, oblong with
a short acuminate apex.
PINNA MIDRIB with
dark, but not always very
obvious, mark on
underside at junction of
pinna and rachis.
LOWEST PAIR OF
PINNAE asymmetrical,
with the basiscopic pinna
segments beside stipe
fully stalked and slightly
larger than the
corresponding acroscopic
pinna segments.
SCALES only moderately
dense, pale gold or brown
with dark bases.
STIPE c. 1/5 - 1/4 leaf length.
HABIT: Plant with erect leaves forming a ‘shuttlecock’ on an erect
rhizome; leaves dying early in winter.
- 162-
Borrer’s Scaly Male Fern {continued)
63c
PINNA SEGMENTS
lying flat in plane of
pinna, lateral margins
with rectangular lobes,
apex variable from
squarely-truncate to
pointed with sharp, acute
teeth usually
prominently longer at
the comers.
BASAL LOBE of pinna
segments beside rachis
on lowest few pairs of
pinnae sometimes
conspicuous and
rectangular.
INDUSIUM thin, low,
soon lifting to reveal the
maturing sporangia,
shrivelling and lifting on
maturity to form a ± flat
or wavy disc, then later a
^chanterelle’ without
radial splits, rarely still
present on last year’s
leaves (x 10).
HABITAT: Woods, hedgerows, open hillsides and mountain scree.
DISTRIBUTION: Throughout the British Isles; possibly the
commonest form, certainly so in the S and E of Britain.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) D. filix-mas, which lacks a conspicuous dark
junction of the pinna midrib and rachis;
(63a, b, d, e) other morphotypes of D. affinis.
-163-
63d Robust Scaly Male Fern
Dryopteris ajfinis (Lowe) Fraser-Jenkins
morphotype robusta (sensu auctt. Brit.)
LEAVES up to c. 100
(-200) cm, lanceolate to ovate-
lanceolate, base truncate
(but less so than 63c),
1-pinnate-pinnatisect, texture
not very firm, upper
surface of lamina not very
glossy.
PINNAE held in plane of leaf,
outline very uneven, oblong
with an acuminate apex.
PINNA MIDRIB with a
dark mark on underside at
junction of pinna and
rachis.
LOWEST PAIR OF
PINNAE very
asymmetrical, with the
basiscopic pinna segments
beside stipe fully stalked
and much larger than the
corresponding acroscopic
pinna segments.
SCALES moderately dense
to dense, gold with dark
bases.
STIPE c. 1/6 - 1/5 leaf length.
HABIT: Plant with erect leaves forming a ‘shuttlecock’ on an erect
rhizome; leaves dying early in winter.
- 164-
Robust Sculy Mule Fern {continued)
63d
PINNA SEGMENTS
lying flat in the plane of
pinnae, margins with
deep rectangular lobes,
apex oblique-truncate to
sharp pointed with acute
teeth.
BASAL LOBE of pinna
segments beside rachis
on lowest few pairs of
pinnae conspicuous and
rectangular.
INDUSIUM similar in
all respects to (63c).
HABITAT: Deciduous woods and rocky gorges, more usually on
calcareous rocks or soils.
DISTRIBUTION: Not completely known; widely scattered
throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) Dryopteris filix-mas, which lacks a conspicuous
dark junction of the pinna midrib and rachis;
(63a, b, c, e) other morphotypes of D. affinis.
- 165-
63e Narrow Scaly Male Fern
Dryopteris affinis (Lowe) Fraser-Jenkins
moqjhotype cambrensis (sensu Fraser-Jenkins)
LEAVES up to c. 100
(-200) cm, oblanceolate to
narrowly elliptical, base
tapering, 1-pinnate-
pinnatisect, texture firm,
upper surface of lamina
sUghtly glossy.
PINNAE held at an angle
to plane of leaf, outline
uneven, oblong to
triangular, with a long
acuminate apex,
PINNA MIDRIB with a
dark mark on underside at
junction of pinna and
rachis.
LOWEST PAIR OF
PINNAE asymmetrical,
with the basiscopic pinna
segments beside stipe fully
stalked and larger than
the corresponding
acroscopic pinna
segments.
SCALES dense, gold to
reddish gold.
STIPE c. 1/6 - 1/5 leaf length.
HABIT: Plant with erect leaves forming a ‘shuttlecock’ on an erect
rhizome; leaves dying through winter.
-166-
Narrow Scaly Male Fern (continued)
63e
PINNA SEGMENTS
lying at an angle to plane
of pinna, margins with
rounded lobes, slightly
curled under, apex
rounded-truncate to
round-pointed with teeth
angled away from apex.
BASAL LOBE of pinna
segments beside rachis
on lowest few pairs of
pinnae conspicuous and
round.
INDUSIUM of medium
thickness but thin at the
edges, rather tall,
maturing to form a ^pie-
crust’, sometimes
splitting radially,
some still present on last
year’s leaves (x 10).
HABITAT: Woods, hedgerows, open hillsides and mountain scree.
DISTRIBUTION: Throughout the British Isles; often locally
dominant in the west, rare or absent in many eastern areas of
Britain.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(62) D. niix-mas, which lacks a conspicuous dark
junction of the pinna midrib and rachis;
(63a, b, c, d) other morphotypes of D. affinis.
-167-
64 Hay-scented Buckler Fern
Dryopteris aemula (Alton) O. Kuntze
LEAVES 15-60 cm
(sometimes longer),
triangular-ovate,
3-pinnate-pinnatifid,
mid-green.
LOWEST PINNAE the
longest, lowermost side of
lowest pair of pinnae very
well developed.
STIPE ± equal to blade
length, dark purple-brown
with an eggshell finish
on both surfaces at base,
grading to green higher
up, base slender.
SCALES very narrowly
triangular, apex tapering,
pale brown.
HABIT: Plant with leaves clustered in loose ‘shuttlecock’ on short,
erect rhizome which has a flat growing-point; leaves tend to stay
green over the winter.
-168-
Hay-scented Buckler Fern (continued)
64
PINNULES turning
upwards giving a distinct
crimped look, minute
glands on both surfaces
(x 10), giving scent of
new-mown hay when
crushed or freshly dried.
INDUSIUM with minute
glands round the jagged
margin (x 10).
HABITAT: A plant of acid woods on granite and other igneous
rocks or sandstone; present in heath-bilberry moorland probably as
a relict; usually a lowland plant, up to 50 m (150 ft) altitude, but
reaching higher altitudes in Ireland where the climate is milder.
DISTRIBUTION: A dominant plant in the SW peninsula of
England, the seaboard of W Scotland and W Irel2md where the Gulf
Stream ameliorates the climate. Its presence in the Weald of Sussex
and other isolated sites in cooler areas is maintained by local high
humidity.
CONSERVATION STATUS: Not unduly threatened.
COMPARE WITH:
(68) D. dilatata, which has a dark, longitudinal, central
stripe in the scales and a broadly ovate leaf.
-169-
65 Rigid Buckler Fern
Dryopteris submontana (Fraser-Jenkins & Jermy)
Fraser- Jenkins
LEAVES 20-60 cm,
triang;ular-lanceolate,
2-pinnate, dull grey-green
and mealy.
Innermost pair of pinnules
on lowest pair of pinnae
± equal in leng;th.
STIPE c. 1/2 (or more) leaf
length, dull pale brown, very
base of stipe enlarged.
SCALES dense, shiny, bright
pale brown, long-pointed,
glandular, but glands easily
lost, mixture of longer,
broader and smaller,
narrower ones.
HABIT: Plant with leaves forming small groups or loose
‘shuttlecocks’ on branching, semi-erect rhizomes; growing point
domed; leaves dying with first frosts.
- 170-
Rigid Buckler Fern (continued)
65
PINNULES widely spaced,
teeth acute, but not
spinulose, dense yellow
^ands on both surfaces,
fragrant when crushed.
SORI large, close-packed
in 2 rows either side of
pinnule midrib.
INDUSIUM margin and
surface glandular.
HABITAT: Very rare, in limestone crevices and amongst scree.
DISTRIBUTION: In mountains of N Wales and NW England.
CONSERVATION STATUS: Restricted by fragile habitat.
COMPARE WITH:
No other Buckler Fern is as obviously glandular as this
one.
- 171-
66 Fen Buckler Fern
Dryopteris cristata (L.) A. Gray
LEAVES 30-60 (-100) cm,
linear-lanceolate, 1- to
2-pinnate, slightly
dimorphic, light green.
STERILE LEAVES with
pinnae lying flat in plane of
blade, lower pinnae
pinnatifid.
FERTILE LEAVES taller
and more erect than
sterile leaves, pinnae
twisted so as to be
almost horizontal, lower
pinnae pinnate.
PINNAE, especially
lower ones, ± triangular
with pinna width > 1/2
pinna length, deeply
lobed, apex blunt.
SCALES sparse, uniform
pale brown, broad, tapering
to an acuminate apex.
STIPE 1/3 - 1/2 leaf length,
pale green-brown, becoming
darker at base, very base of
stipe enlarged.
HABIT: Plant with few, erect leaves on a creeping, branching
rhizome; growing point flat; leaves dying rapidly after frost.
- 172-
Fen Buckler Fern {continued)
66
PINNULE SEGMENT
margins with broad,
incurved, short, spinulose-
tipped teeth, no ^ands on
either surface (x 10).
SORI large, up to 2 mm
diam., borne only in top
1/3 of leaf, almost covering
pinnule segment.
INDUSIUM thin, greenish
and almost translucent until
the spores are ripe, margin
± entire, without glands
(x25).
HABITAT: Fens, marshes and wet, lowland heaths.
DISTRIBUTION: The Broads of East Anglia, and a few sites in
NW Britain.
CONSERVATION STATUS: Very vulnerable to drainage.
COMPARE WITH:
(67) D. carthusiana, which has very conspicuous
spinulose teeth on the margins of the pinna segments.
- 173-
67 Narrow Buckler Fern
Dryopteris carthusiana (Vill.) H.P. Fuchs
LEAVES 40-80 (-120) cm,
narrowly lanceolate,
2-pinnate-pinnatisect, light
to yellowish green.
PINNAE in lower 1/3 of
frond narrowly triangular.
LOWEST PINNA ± equal
in length to pinna above.
SCALES sparse, pale
brown, ± concolorous, hair-
pointed.
STIPE c. 1/2 leaf length,
dark brown below, pale
above, very base of stipe
enlarged.
HABIT: Plant with few, erect leaves on a creeping, sometimes
branching rhizome, not forming a ‘shuttlecock’; growing point flat;
leaves dying rapidly after frost.
-174-
Narrow Buckler Fern {continued)
67
PINNULE SEGMENT
margins with very
conspicuous long,
incurving, sharp,
spinulose-tipped teeth,
no glands on upper surface,
sometimes some minute
sessile ones underneath.
INDUSIUM margin entire,
wavy or slightly toothed,
sometimes with a few
stalked glands on the margin
(x25).
HABITAT: In wet woodlands and lowland fens in Britain.
DISTRIBUTION: Locally common.
CONSERVATION STATUS: Sensitive to serai succession and
artificial drainage.
COMPARE WITH:
(68) D. dilatata, which has scales with a dark central
stripe (except those on stolon plants) and a more
triangular leaf.
-175-
68 Broad Buckler Fern
Dryopteris dilatata (Hoffm.) A. Gray
LEAVES 30-150 cm,
triangular-ovate, 3-pinnate,
darl^ bluish-green;
leaves on stolons may be
distinctly triangular.
LOWEST PINNA PAIR
with lowermost side well
developed.
SCALES sparse, broadly
ovate-deltate with long
acuminate apex, dark
central longitudinal
stripe (stripe lacking on
plants produced on stolons).
STIPE c. 1/3 leaf length,
green on upper surface with
abrupt transition to red-
brown base, lower surface
dark and shiny.
HABIT: Plant with leaves arching and clustered in a ‘shuttlecock’
on a short, ± erect rhizome; growing point domed; leaves staying
green through the early part of winter. Some plants have stolons
originating from leaf axils which will be fast growing and creeping
until 20-30 cm from parent plant when they become erect.
- 176-
Brosd Buckler Fern (continued)
68
A
PINNULES with margins
turning under, with short
spinulose-tipped teeth,
segments not cut to midrib,
no glands on either surface
(x 10), although midribs can
be glandular when young.
INDUSIUM dentate and
sometimes glandular
(x25).
SPORES with dense
tuberculae, looking
darker than those of
D. expansa (x 400).
HABITAT: In hedgebanks, woods and shady mountain ledges.
DISTRIBUTION: Very common throughout the British Isles.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
(67) D. carthusiana, which has narrower leaves,
concolorous scales and a creeping main rhizome;
(69) D. expansa, which is more dissected, has flat
pinnule margins and different spores;
(64) D. aemula, which has glands on both surfaces of the
pinnae, a triangular leaf in adult plants and a dark
purple-brown stipe.
- 177-
69 Northern Buckler Fern
Dryopteris expansa (C. Presl) Fraser-Jenkins & Jermy
LEAVES 70-80 cm in shady
sites 2ind woodland,
10-25 cm on open mountain
boulder scree, triangular-
ovate to triangular,
2-pinnate-pinnatifid, mid- to
p£iie green, not glandular
(x 10) except occasionally
on axes when young.
BASISCOPIC
PINNULES often much
longer than adjacent
ones especially on the
lowest pinnae.
SCALES dense, broadly
ovate-deltate, apex often
abruptly acuminate,
typically uniform brown-
ginger, occasionally with
a darker central
longitudinal stripe
STIPE up to 1/2 leaf length,
brown at base, becoming
pale green above.
HABIT: Plant with leaves slightly arching and forming a sparse
‘shuttlecock’ from a ± erect main rhizome (but see note under
D. dilatata about plants on stolons); growing point domed; leaves
soon dying down in winter except in very sheltered sites.
- 178-
Northern Buckler Fern {continued)
69
PINNULES with edges flat
in plane of pinnules, no
glands on either surface.
PINNULE SEGMENTS
more oval, more
obviously toothed, and
more deeply cut (to
midrib) than D. dilatata,
giving leaf a lacy
appearance.
INDUSIUM margin
often irregularly dentate,
sometimes minutely
glandular (x 25).
SPORES with sparse
tuberculae, looldng
paler than those of D.
dilatata (x 400).
HABITAT: In damp, sheltered crevices in moimtain scree, on rocky
ledges in ravines and narrow upland valleys; more rarely in lowland
woodland in W Scotland.
DISTRIBUTION: Not common. Scattered throughout Scotland,
but mainly in the NW, Grampians zmd S Uplands; N England, in
Cheviots, Teesdale and C Lake District; Wales, in Snowdonia and
south to Carmarthen; not recorded in Ireland.
CONSERVATION STATUS: Vulnerable to grazing pressure in a
few open hill-sites.
COMPARE WITH:
(68) D. dilatata, which is darker green, less dissected,
and has the pinnule margins deflexed;
(67) D. carthusiana (in wet woods), in which the main
rhizome is creeping and the scales lack the dark stripe.
-179-
70 Scaly Buckler Fern
Dryopteris remota (A. Braun ex Doll) Druce
LEAVES c. 80 cm long,
narrowly triangular-
lanceolate, 2-pinnate,
dark green.
PINNAE narrowly
triangular, usually with
darkened midrib at junction
with rachis.
BASISCOPIC PINNULES
of lower pinnae slightly to
much longer than
corresponding acroscopic
ones.
SCALES rather dense,
lanceolate-triangular,
hair-pointed, pale brown
with dark bases.
STIPE variable in length,
c. 1/3 leaf length.
HABIT: Plant with leaves forming a ‘shuttlecock’ on short, erect
rhizome that forms many crowns; growing point ± flat; leaves dying
early in winter.
- 180-
Scaly Buckler Fern (continued)
70
PINNULES with sides
± parallel and with shallow
lobes, apex rounded to
acute, teeth on sides and
apex narrowly acute, no
glands on either surface.
INDUSIUM highly convex
in the young sorus, shrinking
as sporangia ripen and
usudly persisting when
spores have been shed.
SPORES mostly good (but
with a fair number of
abortive ones) (x 400).
HABITAT: Only circumstantial evidence of the Irish habitats exists;
it appears to be a plant of low altitude damp woodland. In mainland
Europe it may reach 1200 m (4000 ft).
DISTRIBUTION: Known in the British Isles only from two records
in W Ireland, but might be found anywhere that both its postulated
parents, D. afftnis and D. expansa, grow or grew.
CONSERVATION STATUS: This species is a triploid apomict of
hybrid origin £md could be either spontaneously formed anew or
perpetuate itself. Very rare, may be extinct.
COMPARE WITH:
Other hybrids between 1- and 2-pinnate species of
Dryopteris, e.g. D. x brathaica, which will have almost
totally abortive spores.
The presence of D. remota in Ireland where D. expansa has not been found
is an enigma. The species was said to be growing at Dalystown, Galway and
living material was sent to I. Manton in 1935 for cytological investigation.
Whilst there is no doubt of its identity, its true provenance must remain
uncertain.
- 181-
71 Hard Fern
Blechnum spicant (L.) Roth
LEAVES 20-65 cm, in
sporing plants of two
lands, the fertile leaves with
a longer stipe, narower
pinnae and standing erect,
the sterile leaves often
spreading close to the
ground.
LEAF-BLADE narrowly
lanceolate to elliptic,
tapering to an acute apex
and usually more abruptly
towards the base, pinnately
divided, the pinnae alternate
and widely spaced giving a
herring-bone appearance,
mid- to deep green, young
leaves pale green.
STERILE PINNAE linear
or sometimes slightly
tapered from the base which
is dilated and adnate to the
rachis, apex obtuse.
RACHIS glabrous, reddish.
STIPE up to 1/3 leaf length,
that of the fertile leaf often
longer, purple-brown, scaly
at base.
SCALES 5-8 mm long,
triangular-lanceolate,
tapered to a fine apex,
purple-brown.
HABIT: A tufted plant with an erect rhizome often branching to
form clumps of several crowns which develop as dense clusters of
leaves; wintergreen.
- 182-
Hard Fern {continued)
71
FERTILE PINNAE almost
lacking any lamina other
than a narrow band that
bears the sorus either side
of the midrib.
SORUS linear, running the
whole length of the pinna,
close to the midrib,
indusiate.
INDUSIUM lineEir, turgidly
enclosing the entire sorus
and only shrinking and
exposing the entire sorus at
the end of the season.
HABITAT: A marked calcifuge and a common associate of acid
woodland on peat and sandy soils, open moorland, lowland heaths
and mountain ravines, from sea-level to 1220 m (4000 ft).
DISTRIBUTION: Throughout the British Isles but uncommon in
areas with clay soils.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
There is no other species similar to this in the British flora, but
two species of Blechnum are grown in gardens and occasional!
escape onto hedgebanks and moorland.
!A) B. penna-marina (Poir.) Kuhn
New Zealand) has a similar leaf-
orm to young ti. spicant, but it has a
vigorous creeping rhizome and much
smaller leaves at maturity;
(B) B. cordatum (Desv.) Hieron.
(Cnile) is a much larger, creeping
?lant with thick, coriaceous leaves,
2 cm or more broad- even sporelings
have an ovate leaf which is not
decrescent below and would not be
confused with B. spicant.
- 183-
72 Water Fern
Azolla filiculoides Lam.
A distinct and atypical fern
in a family by itself
(AzoUaceae). It is
completely free-floating and
has a copiously branched,
horizontal stem with
extremely small leaves.
LEAVES sessile, alternate,
in two rows on the dorsal
side of the stem, bilobed;
upper leaf-lobe c. 2.5 x
1-1.5 mm, ovate with an
obtuse apex, glaucous green,
epidermal cells bearing a
single papilla on the outer
wall (x 40), the underside
with cavities containing the
blue-green dXgaiAnabaena,
(living in symbiosis and able
to ‘fix’ atmospheric
nitrogen); the lower leaf-
lobe often submerged,
colourless.
HABIT: Normally a floating plant forming a dorsi-ventral branched
system rooting from the horizontal stem; occasionally terrestrial as
open water dries up in summer; leaves turning deep crimson at
onset of winter and plants dying back to just small buds which lay
dormant or sink to pond bottom until a rise in temperature
promotes new growth in spring.
- 184-
\VatCr Fern {continued)
72
SORUS a globose body known as a SPOROCARP which contains
either micro- or megasporangia, borne on the first leaf of a lateral
branch, the lower leaf-lobe forming the sporocarp zmd the upper
leaf-lobe forming a false indusium covering the sporocarp (x 100).
MICROSPOROCARPS
contain numerous sporangia,
each contziining 64
microspores (x 400).
MEGASPOROCARPS
contain only one
megasporangium in which a
single megaspore develops
(x 200).
Both kinds of spores are associated with complex
t dispersal structures formed from reorganised inner
sporangial wall, known as ‘massulae’, in which the
microspores are embedded and bearing barbed,
anchor-like outgrowths, glochidia\ and ‘floats’, to
which the megaspore is attached. These characters are
used in species delimitation.
GLOCHIDIA composed of a single cell (i.e. not
septate) (x 400).
HABITAT: In ponds and other bodies of still water, ditches, and
at the edges of slow-flowing streams amongst riparian vegetation; it
can rapidly cover the available water surface to the extent that
individual plants may grow over each other.
DISTRIBUTION: Mainly in the south of England, but found as far
north as the Isle of Man and Yorkshire; in Ireland in W Cork amd
Wicklow.
CONSERVATION STATUS: Not threatened.
COMPARE WITH:
Azolla mexicana A. Br. {A. caroliniana auct.), another American
species has been recorded in W Europe and may be found in the
British Isles. It has two papillae on each leaf (upper) epidermal cell
and septate glochidia on the massulae.
- 185-
A1-A6 Alien Ferns and Spikemoss
Introduction
Exotic plants grown in the gardens, conservatories and houses
of Britain and Ireland, if they produce propagules of any kind, may
spread from time to time beyond the boundiu’ies of the original site
of introduction. Depending on their climatic and ecological
requirements, their presence in the invaded habitat may be short-
lived or of longer duration. The most ephemeral do not even survive
the colder days of the following winter. Others may find a niche
well-suited to their mode of living and flourish in it for a long time
(e.g. Cyrtomium falcatum on the shore of St Mary’s, Isles of Scilly,
first found in 1956, and still there in 1990, in spite of violent storms
battering the coast).
We have described, albeit briefly, five species of alien ferns and
one spikemoss, accepting a further species, y42o//a filiculoides, as
sufficiently well-established to be included in the main body of the
text (as No. 72). These alien species (A1-A6) are those which have
been found growing wild in several locations and/or intermittently
over a long period of time. There will be others that from time to
time establish themselves from spores blown onto a damp wall or
that get thrown out with garden rubbish. Two examples of this are
mentioned on p. 183: Blechmtm cordatum (syn.: B. chilense) and
B. penna-marina occasionally escape into moorland areas. Another
fern, grown in more clement areas and establishing itself outside
gardens as sporelings, is the tree-fern, Dicksorua. Possibly two
species, D. antarctica Labill. and D. fibrosa Colenso, are involved.
Young plants without a trunk would resemble a Dryopteris, but will
have hairs, not scales, on the rhizome apex.
Readers wishing to identify cultivated ferns should consult the
literature given below. Any well-established pteridophyte that
proves to be an alien should be monitored carefully, especially if
there is the likelihood of it ousting native species (of any group)
from the plant community it has adopted.
References on exotic ferns
Jones, D.L. 1987. Encyclopaedia of Ferns. British Museum (Natural
History), London.
Kaye, R. 19^. Hardy Ferns. Faber & Faber, London.
Page, C.N. & Bennell, F.M. 1984. Pteridophyta in S.M. Walters et al.
The European Garden Flora. University Press, Cambridge.
Rush, R. 1984. Guide to Hardy Ferns. Brit. Pteridological Soc., London.
-186-
Krauss’s Spikemoss
Selaginella kraussiana (G. Kunze) A. Braun
A1
FERTILE LEAVES and SPORES
as in (7) S. sela^noides, but
forming cones 7-12 mm long on
side branches.
A prostrate plant with slender,
branched and intertwined stems
rooting frequently at branch
intersections. If well-
established and sheltered can
form a mat, but usually
fragmented due to die-back in
winter.
This species is in the much
larger, and mainly tropical,
section of the genus which has
LEAVES of two kinds: lateral
leaves, 1.5-2.5 mm,
asymmetrical, ± linear-oblong,
lying in one plane ± at right-
angles to the stem, opposite or
diametrically opposed, well-
spaced on main stem, closer,
often touching on branches;
median leaves (best seen on
branches, those on main stem
not obviously smaller than
lateral leaves), 0.5-1 mm,
ovate-lanceolate, drawn to an
acute tip, lying centrally
between the larger leaves and
± parallel to the stem.
HABITAT: Hedgebanks, roadsides and amongst low vegetation,
usually not far from habitation and point of introduction.
DISTRIBUTION: Now established quite extensively in more
clement lowland areas in W Britain and in Ireland; native to the
Azores, Madeira, tropical and S Africa, and grown as a conservatory
plant for ground-cover.
COMPARE WITH:
No other similar species in the British flora.
-187-
A2 Ladder Brake
Pteris vittata L.
A3 Cretan Brake
Pteris cretica L.
Both species have few leaves arising from a short-creeping rhizome.
LEAVES of both are from 10 cm (in depauperate specimens on wails) to
40 (-70) cm long, pinnate, with the apical pinna longer and larger
than lateral pinnae (clearly seen, even in very young specimens).
PINNAE of (A2) < 7 cm, 10-25
pairs, narrowly triangular to
linear, finely serrate, the base
often auriculate, shortly petiolate.
PINNAE of (A3) 15 cm or
more, 1-5 pairs, strap-like,
the lowest with an extended
basiscopic segment.
STIPE of(A2)
5-10 cm, densely
covered vrith
triangular,
attenuated, fawn or
whitish scales; that
of (A3), 1/2 leaf
length, glabrous.
SORUS continuous
along pinna margin,
indusiate.
HABITAT: Cultivated as house plants, they establish themselves
in rocky (including man-made) habitats where a frost-free climate exists,
e.g. outhouse walls, wells and sunken culverts, and colliery slag heaps.
DISTRIBUTION: Occasionally in the south and along the western
seaboard of Britain; a large colony of (A2) established itself on a disused
coal tip in W Gloucestershire in 1964, but not seen there recently, the
habitat now cooled and overgrown.
COMPARE WITH:
(32-34) Polypodium species (especially cultivars) can superficially be
similar when growing on dry walls, but the absence of an apical pinna
much larger and longer than the lateral ones, the adnate pinnae and
position of sori clears any doubts.
-188-
Chinese Holly Fern
Cyrtomium falcatum (L. fil.) C. Presl
Plant with an erect, densely
scaly rhizome with an open
cluster of leaves up to ^ cm
(or more in lush situations,
but much smaller when in dry
habitats.)
LEAF-BLADE linear-oblong
to ovate-lanceolate, pinnate,
leathery, glossy, deep green.
PINNAE up to 6 cm long,
ovate-linear, irregularly
toothed, apex acuminate,
falcate, terminal pinna often
tripartite or diamond-shaped.
STIPE, 1/5-1/3 leaf length,
green, scaly.
SCALES 6-10 mm long, ovate,
golden to dark brown.
SORI discrete, circular,
scattered, indusiate.
HABITAT: A plant that likes to wedge its rhizome between rocks,
in moist exposed places, hedgebanks etc.
DISTRIBUTION: A native of E Asia, grown as a pot plant and in
conservatories in the British Isles; established in the Scilly and
Channel Isles, and occasionally on warm, moist walls in towns in
S and SW Britcdn.
COMPARE WITH:
Although young plants are similar to Polystichum species,
the fewer, broader, net-veined pinnae, and distinct terminal
pinna separate this species.
A5 Sensitive Fern
Onoclea sensibilis L.
Plant with a thick (6-12 mm)
far-creeping, branching rhizome
with leaves arising at intervals;
dying down in autumn.
LEAVES of two kinds: sterile
leaves 40-70 cm long,
triangular-ovate, pinnate at
base, pinnatisect above, at first
reddish becoming vivid green;
fertile leaves shorter than
sterile, lamina ± lacking,
red-brovm, becoming brown
and persisting through the
winter.
PINNAE 5-8 pairs, 7-16 cm long,
elliptic, margin entire or wavy
at leaf apex to deeply lobed
below, basal pinnae stalked;
veins anastomosing.
STIPE 2/5 leaf length,
glabrous, stramineous, red-
brown at base.
SORUS round, 1-2 at base of
each lobe covered bv
inrolled apex, the whole a
purplish colour, hardening
and persisting through the
winter.
INDUSIUM membranous,
soon lost.
SPORES green, shed the
following spring.
HABITAT: Wet lake margins and areas where ground water
seeps. Frequently grown in gardens where it quickly spreads.
DISTRIBUTION: In damp woodland and marshy meadows mostly
in southern and western Britmn and in Ireland; a few well-
established populations exist in Cumbria some distance from an
obvious source of introduction; a North American species.
COMPARE WITH:
Even in the vegetative state the leaf-shape and rhizome of this
species can be easily identified. However, young leaves of
this species and (24) Osmunda regalis can be very similar in
shape and texture, but Osmunda has free, not reticulate, veins.
- 190-
Ostrich Fern
Matteuccia struthiopteris (L.) Tod.
A6
Plants with an erect rhizome,
forming large and attractive
‘shuttlecoclu’ but also bearing
long-creeping stolons at the end
of which new plants arise.
LEAVES of two kinds; the
sterile up to 140 cm long, the
fertile often half that length,
lacking green lamina tissue.
LEAF -BLADE oblanceolate,
pinnate-pinnatisect, a rich, fresh
green, not glandular.
PINNAE up to 15 cm long, the
lower pairs markedly
decrescent, lobes Unear-
oblong, apex bluntly rounded or
truncate.
STIPE 1/4 length of sterile leaf,
< 1/2 that of fertile leaf, glabrous,
base spathulate.
INDUSIUM membranous, soon
lost.
SPORES green, shed following
spring.
SORUS round, 1-2 at base
of each lobe covered by inrolled
apex, the whole a purplish
colour, hardening and
persisting throng the winter.
HABITAT: In wet woods on heavy clay soils; prefers water
percolating through its roots.
DISTRIBUTION: Scattered throughout the British Isles; widely
grown as an ornamental, but easily escapes by means of its stolons
which can be over 10 m long; native of N America and N Europe.
COMPARE WITH:
(38) Oreopteris limhosperma which is very glandular and bears
sori on leaves with green lamina tissue.
- 191-
Index to Latin names
Figures given mostly refer to species numbers; page numbers are given
for taxa only referred to in discussion. Synonyms are ffven in italics.
Adiantum capillus-veneris 27
Blechnum chilense
p 186
Anogramma leptophylla 26
cordatum
p 183
Asplenium adiantum-nigrum 40
penna-marina
p 183
subsp. onopteris
=41
spicant
71
adulterinum
pill
Botrychium lunaria
20
X altemifolium
47 X 44a
matricariifolium
p 49
billotii
=42
Ceterach officinarum
= 48
ceterach
48
Cryptogramma crispa
25
X clermontiae
46 X 44b
Cyrtomium falcatum
A4
X confluens
39 X 44b
Cystopteris dickieana
54
X contrei
40x47
frag^s
53
cuneifolium
p97
montana
55
X jacksonii
40x39
Dicksonia antarctica
p 186
marinum
43
fibrosa
p 186
X microdon
42x39
Diphasiastrum alpinum
5
X murbeckii
46x47
complanatum
obovatum
morph, decipiens
6
subsp. obovatum
p 101
subsp. alpinum
= 5
subsp. lanceolatum
42
subsp. complanatum
p 15
onopteris
41
subsp. issleri
p3
ruta-muraria
46
X issleri
p3
subsp. dolomiticum
p 113
Dryopteris abbreviata
= 61
X samiense
40x42
aemula
64
scolopendrium
39
affinis
63
septentrionale
47
morph, afflnis
63a
X ticinense
40x41
morph, borreri
63c
trichomanes
morph, cambrensis
63e
subsp. inexpectans
p 109
morph, paleaceolobata 63b
subsp. pachyrachis
44c
morph, robusta
63d
subsp. quadrivalens
44b
subsp. stilluppensis
= 63e
subsp. trichomanes
44a
X ambroseae
68x69
trichomanes-ramosum 45
assimilis
= 69
viride
= 45
austriaca
= 68
X Asplenophyllitis
borreri
= 63c
confluens =
=39 X 44b
X brathaica
67 X 62
jacksonii
= 40x39
carthusiana
67
microdon
= 42x39
X complexa
63x62
Athyrium alpestre
= 50a
nssp. complexa
63a X 62
distentifolium
nssp. contort a
63e X 62
var. distentifolium
50a
nssp. critica
63c X 62
var. flexile
50b
cristata
66
filix-femina
49
X deweveri
67x68
flexile
= 50b
dilatata
68
Azolla filiculoides
72
expansa
69
caroliniana
p 185
filix-mas
62
mexicana
p 185
X mantoniae
62 X 61
192
Index to Latin names (continued)
Dryopteris (continued)
Oreopteris limbosperma
38
oreades
61
Osmunda regalis
24
X pseudoabbreviata
64x61
Phanemphlebia falcata
=A4
pseudomas
=63a
Phegopteris connectilis
37
remota
70
Phyllitis scolopendrium
=39
X sarvelae
67x69
Pilularia globulifera
28
submontana
65
Polypodium australe
=34
X uliginosa
67x66
cambricum
34
villarii
=65
X font-queri
34x32
subsp. submontana
=65
inteijectum
33
Equisetum arvense
15
X mantoniae
33x32
X bowmanii
17x19
X shivasiae
34 X 33
X dycei
14x18
vulgare
32
fluviatile
14
Polystichum aculeatum
59
X font-queri
18x19
X bickneUii
59x60
hyemale
11
X illyricum
59x58
X litorale
15x14
X lonchitiforme
58x60
X mildeanum
16 X 17
lonchitis
58
X moorei
11x12
setiferum
60
palustre
18
Pteridium aquilinum
pratense
16
morph, aquilinum
35a
ramosissimum
12
morph, latiusculum
35b
sylvaticum
17
Pteris cretica
A3
telmateia
19
vittata
A2
X trachyodon
11x13
Selaginella kraussiana
A1
variegatum
13
selaginoides
7
Gymnocarpium dryopteris 51
Thelypteris dryopteris
= 51
robertianum
52
limbosperma
=38
Huperzia selago
4
palustris
36
Hymenophyllum tunbrigense 29
phegopteris
=37
wilsonii
30
robertiana
= 52
Isoetes brochonii
p 19
thelypteroides
echinospora
9
subsp. glabra
= 36
X hickeyi
p 19
Trichomanes spedosum
31
histrix
10
Woodsia alpina
57
lacustris
8
ilvensis
56
Lycopodiella inundata
3
Lycopodium alpinum
= 5
annotinum
1
clavatum
2
inundatum
=3
selago
=4
Matteuccia struthiopteris A6
Onoclea sensibilis A5
Ophioglossum azoricum 22
lusitanicum 23
vulgatum 21
-193-
Index to English names
Figures given refer to species numbers
Adder’s Tongue
21
Lady Fern
49
Least
23
Alpine
50a
Small
22
Flexile Alpine
50b
Beech Fern
37
Lemon-scented Fern
38
Bladder Fern
Maidenhair Fern
27
Brittle
53
Male Fern
62
Dickie’s
54
Mountain
61
Mountain
55
Scaly
63
Bracken
35a
Borrer’s
63c
Northern
35b
Greater Western
63b
Brake
Narrow
63e
Cretan
A3
Robust
63d
Ladder
A2
Western
63a
Buckler Fern
Marsh Fern
36
Broad
68
Moonwort
20
Fen
66
Oak Fern
51
Hay-scented
64
Limestone
52
Narrow
67
Ostrich Fern
A6
Northern
69
Parsley Fern
25
Rigid
65
Pillwort
28
Scaly
70
Polypody
Clubmoss
Common
32
Alpine
5
Intermediate
33
Fir
4
Southern
34
Interrupted
1
Quillwort
Lesser
7
Common
8
Marsh
3
Land
10
Stag’s Horn
2
Spring
9
YeUow Cypress
6
Royal Fern
24
Filmy Fern
Rustyback
48
Tunbridge
29
Sensitive Fern
A5
Wilson’s
30
Shield Fern
Hard Fern
71
Hard
59
Hart’s Tongue
39
Soft
60
Holly Fern
58
Spleenwort
Chinese
A4
Acute-leaved
41
Horsetail
Black
40
Branched
12
Common Maidenhair
44b
Field
15
Delicate Maidenhair
44a
Great
19
Forked
47
Marsh
18
Green
45
Rough
11
Lanceolate
42
Shade
16
Lobed Maidenhair
44c
Variegated
13
Sea
43
Water
14
Wall Rue
46
Wood
17
Woodsia
Jersey Fern
26
Alpine
57
Killamey Bristle Fern
31
Oblong
56
Krauss’s Spikemoss
A1
Water Fern
72
- 194-
t
s
1
L
* M ■, i
:
rif
■'• ■ I
f
I'
/
I
Written by two experts on the staff of the Botany department at
The Natural History Museum, London, The Illustrated Field Guide
to Ferns and Allied Plants of the British Isles is a definitive account
of the species of ferns and allied plants encountered in Britain and
Ireland.
The guide gives keys to and descriptions of all native species and a
number of aliens that may be found. The salient diagnostic points
are clearly listed against line drawings made by Peter Edwards
(pteridologist at the herbarium of the Royal Botanic Gardens,
Kew). Notes on habitat requirements, distribution, conservation
status, and species with which each can be confused, and lists of the
hybrids found in each genus are given.
The guide has been compiled with both the serious student and the
general natural historian in mind, and beginners in botany will find
the work invaluable.
Other Fern Titles From Natural History Museum Publications
A World of Ferns
J. Camus, C. Jermy & B. Thomas
Encyclopaedia of Ferns (UK sales only)
D.L. Jones
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11