Webb's An Irish Flora

By John Parnell and Tom Curtis

This handbook will provide the reader with a clear and reliable means of identifying those plants which grow wild in Ireland. This book is a comprehensive re-working of the classic and standard Flora of Ireland which was last published 16 years ago: this will be the eighth edition of that work. It has been brought fully up to date through incorporating the latest in botanical research and it reflects contemporary and modern approaches to plant classification based on recent advances in genetics.

Trees, shrubs and climbers in winter are now covered for the first time. Also included is a list of plants that have legal protection in Ireland. Webb’s an Irish Flora is illustrated throughout with hand-coloured drawings.

...this flora remains the most useful pocket guide to the Irish flora-National Botanic Gardens, Glasnevin

This handy reference book for botanists both amateur and professional, gardeners, hill walkers, students, farmers and naturalists. It is about the higher plants that grow wild and which are commonly naturalised or otherwise encountered in Ireland. It is designed to help you identify and provide you with background information on plant morphology, distribution and rarity and to educate all those interested in recognising the species of the flora of Ireland.

Previous editions of the book have been used by workers outside of the specific field of study of plant identification – such as environmental consultants, the general public, students, professional and amateur botanists etc. There is a genuine demand for a Flora whose subject matter refers explicitly to Ireland whilst placing that flora in a wider context. Furthermore, a concise flora of a discrete geographical area is of interest internationally to many professional and amateur botanists and gardeners. The book has, is and will be used in student training (it is used as a basic botanical text book in some Universities in Ireland) and on training courses for professionals wishing to improve their skills and for all those needing to improve their levels of botanical expertise.

• Language: English
• Publisher: Cork University Press
• Release date: Mar 1, 2012
• ISBN: 9781909005099

John Parnell

About the author: Mr. Parnell holds teaching certification in physics, chemistry, biology, general science, mathematics, and business and distributed education. Over the course of forty years of teaching, he has taught students from the sixth grade through graduate school. In addition, Mr. Parnell has taught for the New York State Research Foundation preparing students for the SAT exam in mathematics.

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DESCRIPTIONS OF FAMILIES, GENERA AND SPECIES

LYCOPHYTES

Plants without flowers, producing spores, not seeds and with leaves virtually always (always in Irish species) containing only a single, unbranched vein. The spores are all similar in the Lycopodiaceae, but in the Selaginellaceae and Isoetaceae they are differentiated into large megaspores and much smaller microspores, both borne on the same plant.

1.  LYCOPODIACEAE. Clubmoss

Plants of somewhat moss-like habit, but more robust. Leaves numerous, small, undivided. Sporangia borne singly in leaf-axils or in dense cones, all alike, with small spores.

1. Lycopodium

Lycopodium clavatum. 6–9. Stems prostrate, rooting, up to 50 cm long, sparingly branched; branches short, erect, many of them ending in cones. Leaves linear-oblong, with a white, hair-like tip, numerous, crowded except in the region below the cones, where they are sparse and widely spaced. Wet heaths and grassy mountain slopes; rare and declining.

2. Lycopodiella

Lycopodiella inundata (Lycopodium inundatum). Marsh clubmoss. Garbhógach chorraigh. 6–9. Stems short, sparingly branched, prostrate at the base but erect at the tip; some branches bearing terminal, erect, poorly defined cones. Leaves linear lanceolate, shortly pointed, those of the cones broader at the base. Lake-margins and wet bogs. Occasional locally in the west and south-west; very rare elsewhere.

3. Huperzia

Huperzia selago (Lycopodium selago). Aiteann Muire. 6–8. Stem sturdy, erect, 5–12 cm high, forked 1–2, rarely more, times. Leaves all alike, 5–7 mm long, oval-lanceolate. Sporangia situated in leaf-axils here and there, not aggregated into distinct cones. Bud-like bulbils are often present in the leaf-axils in place of sporangia; these become detached and serve for vegetative reproduction. Mountain cliffs and wet heaths, mostly above 300 m, but sometimes on lowland bogs; frequent but local.

4. Diphasiastrum

Diphasiastrum alpinum (Diphasium alpinum, Lycopodium alpinum). 6–8. Main stem prostrate, often buried, with widely spaced alternate leaves; from this, branches arise which themselves are repeatedly branched, forming fan-shaped structures, bearing pale bluish-green, lanceolate, acutely pointed leaves arranged in four longitudinal rows. Cones terminal, not very clearly differentiated. Montane heaths and grasslands or bare peat on mountain ridges and summits, from Counties Wicklow and Galway northwards; formerly in County Kerry but apparently extinct there; rare.

2. ISOETACEAE

Isoetes

Submerged, aquatic perennials. Leaves linear, pointed, arranged in a dense rosette, each leaf swollen at the base and traversed inside by 4 longitudinal aircanals. Sporangia situated in a pouch at the base of some of the leaves, covered by a membrane, those on some leaves containing a few large megaspores, on others containing numerous small microspores [Fig. 2a].

1. Isoetes lacustris. 5–9. Leaves 10–25 cm long (rarely more), fairly stiff and brittle, dark green, tapering rather suddenly near the tip to a fine point. Megaspores greyish-white, marked with a fine pattern of ridges, but without spines. In shallow or fairly deep water at the margins of acid lakes, mainly in the north and west; occasional.

2. I. echinospora (I. setacea). 5–9. Like I. lacustris, but leaves rather shorter, soft and flexible, tapering uniformly from base to tip. Megaspores chalky white, covered with small spines. Shallow water in acid lakes; occasional near the west coast, unknown elsewhere.

Fig. 2a

Fig. 2b

Fig. 2c

3.  SELAGINELLACEAE

Selaginella

Plants of somewhat moss-like habit, with numerous small leaves. Sporangia of two kinds, both situated in the leaf-axils of rather ill-defined terminal cones; some (megasporangia) containing 4 large spores, others (microsporangia) containing numerous small spores.

1. Selaginella selaginoides. 6–8. Stem erect, from a creeping base, 2–10 cm high. Leaves alternate, lanceolate, acute, finely toothed, sometimes tinged with pinkishbuff; those in the cones a little larger than the others, but otherwise similar. Megasporangia situated at the base of the cone, more numerous than the microsporangia higher up. Marshes, fens, damp hollows in sandhills and mountain ledges; frequent in the north, occasional in the centre, rare in the south.

2. *S. kraussiana. 7–9. Stems creeping, bearing flattened sprays of foliage; leaves arranged in four longitudinal rows, those at the sides of the stem 2 mm long, oval lanceolate, acute; those on the top and beneath only half as long. Cones rarely produced, short, 4-angled, with oval, abruptly pointed, keeled leaves. Cultivated in greenhouses and occasionally naturalised on lawns, paths and roadside banks, mainly in the south and west. Native of the Azores and Africa.

MONILOPHYTES (Ferns)

Plants without flowers, producing spores, not seeds and with leaves usually containing multiple and branched veins. In most species the spores are all similar but in the Marsiliaceae and Salviniaceae they are differentiated into large megaspores and much smaller microspores, both borne on the same plant.

4.  OPHIOGLOSSACEAE

Small ferns with an underground stem, which lacks scales and, usually, with only one leaf at a time; this is divided into two quite distinct portions – an ordinary, leaf-like blade, and a fertile spike, bearing sporangia, which stands up in front of the leaf-like portion.

1. Botrychium

Botrychium lunaria. Moonwort. 6–8. Blade of leaf 3–8 cm long, deeply pinnately divided, with about 6 pairs of fan-shaped segments. Fertile spike usually taller and irregularly branched. Sporangia prominent, not sunken. Grassland, heaths, open woodland and mountain ledges; widespread but rare.

2. Ophioglossum. Adder’s tongue

Blade of leaf undivided; spike unbranched; sporangia sunken.

1. Ophioglossum vulgatum. 5–8. Leaves usually single. Blade of leaf oval, more or less erect, 4–15 cm long; fertile spike slender, nearly cylindrical, with a row of 10–40 sporangia on each side. Pastures, meadows and rocky ground; occasional.

2. O. azoricum. 5–8. Differing from O. vulgatum in its more slender habit with the leaves somewhat spreading and often produced in pairs; the blade narrow, often lanceolate, 3–3.5 cm long and in the fertile spike with only 6–14 sporangia on each side. Dune-slacks and coastal grassland in the west and possibly in County Down; rare and local.

5. EQUISETACEAE

Equisetum. Horsetail

Perennials, with creeping, underground rhizome. Stems usually erect, unbranched or branched, longitudinally ridged, impregnated with silica and, thus, usually rather harsh to the touch. Leaves small, whorled, united at the base to form a tubular sheath surrounding the stem or branch, and ending in acute teeth which are usually brown, black or white. Spores all alike; sporangia borne on small, mushroom-shaped structures grouped to form a terminal cone.

Fig. 5a

Fig. 5b

Fig. 5c

Fig. 5d

Fig. 5e

Fig. 5f

1. Equisetum hyemale. 7–8. Stems all alike, some bearing cones, erect, rough, unbranched, not very thick-walled, with about 20 conspicuous ridges and grooves, evergreen, 35–100 cm high, 5–6 mm in diameter. Sheaths 4–6 mm long, close-fitting, whitish, with a narrow black band at the top and another at the bottom which broadens with age so as almost to join the upper band; teeth soon disappearing. Cone with a short, sharp point. Damp, open woods and riverbanks, mainly in the east; rather rare.

2. E. ×moorei. Moore’s horsetail. Scuab eich an Mhóraigh. 7–8. Similar to E. hyemale, but the stems are less robust and only 3–4(–5) mm in diameter; they are less reliably evergreen and tend to die back, at least at the tips, in winter, and usually a few slender teeth persist on the leaf-sheaths. Cones infrequent and the spores apparently abortive. Sandhills and clay banks by the sea; locally frequent on the east coast in Counties Wicklow and Wexford; unknown elsewhere.

A supposed hybrid between E. hyemale and another species; the second parent is said on cytological grounds to be E. ramosissimum, but as this has never been recorded for Ireland, and even in Britain is only a rare alien, the parentage must be considered uncertain.

3. E. variegatum. 7–8. Very variable. Stems erect or prostrate, slender, usually not more than 3 mm in diameter and often less, unbranched, or with a few long, wiry branches from near the base; some bearing cones, all hard, thick-walled (with central cavity occupying about one third of the total diameter), with 6–8 ridges and grooves. Leaf-sheaths with a conspicuous black band at the top and sometimes also at the base, and persistent teeth with broad, translucent margins and a thin black midrib [Fig. 5d]. Cone sharply pointed. In base-rich habitats, by lakes and canals, in fens, and damp hollows in sandhills; occasional in the centre, rather rare elsewhere.

4. E. ×trachyodon. 6–8. Like E. variegatum, but stems usually erect, up to 5 mm in diameter, with 8–12 ridges and grooves; leaf-sheaths mainly black, with nonpersistent, slender, mainly black teeth [Fig. 5c]. Spores abortive. Riversides, calcareous lake-shores and wet woods which are base-rich, mainly in the north and west; widespread but rare.

A hybrid between E. hyemale and E. variegatum, but often found in the absence of both parents.

5. E. fluviatile (E. limosum). 6–7. Stems all alike, up to 140 cm, erect, unbranched or with a few branches irregularly disposed, more rarely with regular whorls of branches, smooth and fairly soft, with 10–25 very low and inconspicuous ridges, very thin-walled, with the central cavity occupying at least four-fifths of the total diameter [Fig. 5a]. Leaf-sheaths green, with persistent, acute, black teeth. Cones rounded at the tip. Ditches, wet marshes and shallow water at the margins of lakes and canals; very frequent.

6. E. ×litorale. 6–8. A hybrid between E. arvense and E. fluviatile, but sometimes found in the absence of both parents. It is in most features intermediate between the parents, with erect stems up to 100 cm high and 1.5–3 mm in diameter, usually with regular whorls of branches in the middle part, but unbranched above and below; ridges and grooves 8–10, moderately well-marked. Central hollow occupying about half the diameter; this means that when compressed between finger and thumb it yields, but springs back when the pressure is released. Branches 4- or 5-angled; their leaf-sheaths loose-fitting. Sheaths of main stems green, with persistent, acute, black teeth. Cones short, rounded; spores abortive. Ditches and rocky lake-shores; frequent in most districts.

7. E. arvense. 4–5. Fertile stems appearing in spring, unbranched, white or pale brown, with terminal cone 2–3.5 cm long; leaf-sheaths very loose-fitting, with 10–18 slender, brown teeth. Vegetative stems appearing about a month later, green, with regular whorls of branches which are at first directed obliquely upwards, with about 12 fairly prominent ridges and grooves, thick-walled, with the central cavity occupying less than a third of the total diameter. Branches 4-angled with entirely green, rather loose-fitting sheaths, their lowest internode usually much longer than the adjacent sheath on the main stem. Roadsides, waste-places, railway tracks and other bare ground, usually in drier habitats than other species of the genus; also as a persistent garden weed; abundant.

8. E. pratense. 5. Stems eventually all alike, but the fertile stems (which are rarely produced) are at first unbranched. Vegetative stems 10–35 cm high, rough, 2–3 mm wide, with the central cavity occupying at least half of the total diameter, regularly branched. Branches very slender, 3-angled, flexuous, horizontal or drooping. Leaf-sheaths of the main stems green; teeth persistent, with translucent margins and a narrow, dark-brown midrib. Damp, shady places, from County Fermanagh northwards; occasional.

9. E. sylvaticum. 5. Fertile stems at first unbranched, later branching and coming to resemble vegetative stems, which are up to 50 cm high and 2–4 mm wide, with the central cavity occupying one third or less of the total diameter. They bear 3- or 4-angled branches in regular whorls; these in turn all bear a few secondary branches. Leaf-sheaths on the main stems long, with persistent, rather broad brown teeth, which usually adhere by their edges into groups. Stream sides, cliffs and damp woods, mainly in mountain districts; frequent in the north and south, occasional elsewhere.

10. E. palustre. 6–7. Stems all alike, resembling in general appearance the vegetative stems of E. arvense, but with only 5–9 ridges and grooves and a very small central hollow; teeth of leaf-sheath obtuse, with the margin whitish-translucent and sharply contrasting with the black, central area of the teeth; branches rather fewer, 4- or 5-angled, more or less erect, their lowest internode shorter than or equalling the sheath on the main stem. Ditches, marshes and damp grassland; abundant.

The hybrid between E. palustre and E. telmateia (E. ×font-queri), which is intermediate in all aspects between these two species, has been recently reported from Ben Bulben, County Sligo, and may well occur elsewhere.

11. E. telmateia (E. maximum). 4. Fertile shoots unbranched, white, up to 25 cm, dying away as soon as spores have been shed; cone 5–8 cm long. Vegetative shoots appearing about a month later, up to 150 cm high and 6–9 mm wide, white, with 18–30 low ridges and grooves, with numerous green whorled, slender, drooping branches up to 15 cm long, each with 4–5 double ridges. Leaf sheaths on main stem greenish, with a brown band at the top and numerous acute, brown teeth. Damp hedgerows and banks; frequent but local.

6.  OSMUNDACEAE

Osmunda regalis. Royal fern. 6–8. Stem short, erect, stout. Leaves large, 60–100 cm long, twice-pinnate; young stalks covered in golden-brown hairs which soon fall off. The outer leaves are entirely green and leaf-like with parallel-sided, obtuse segments, about 3 times as long as broad, undivided or lobed at the base. The lower segments of the inner leaves are similar but the upper segments are reduced to clustered masses of brown sporangia, without any leafy tissue. Ditches, bogmargins, damp woods and riverbanks; very frequent in most of the western half, much rarer in the east.

7. HYMENOPHYLLACEAE

Small, evergreen ferns with slender, creeping, black rhizomes and deeply divided leaves, which are very thin and of a dark, translucent green. Sori marginal.

1. Hymenophyllum. Filmy-fern

Small plants, moss-like in habit. Rhizome thread-like; almost hairless. Ultimate divisions of leaves with small, distinct teeth. Indusium consisting of two nearly circular flaps, united only in their lower half. Sorus short, not projecting beyond indusium.

Fig. 7a

Fig. 7b

1. Hymenophyllum tunbridgense. 6–7. Leaves 2–6 cm long, dark, somewhat pale bluish-green; blade flat, at least half as broad as long, irregularly divided into oblong segments. Veins stopping just short of the margin. Flaps of indusium circular, irregularly toothed at the tip [Fig. 7a]. Boulders and tree-stumps in moist woods, by streams, sheltered crevices mainly in mountain areas, and similar places in the lowlands; occasional in the south-west, rare elsewhere.

2. H. wilsonii. 6–7. Similar but with the leaf a pure, deep green, the leaf tip and margins slightly recurved so as to make the surface somewhat convex above; the blade of the leaf at most a quarter as broad as long, with the veins reaching the margin and the tip of the indusium without teeth [Fig. 7b]. Similar situations, but more frequent and on higher ground.

2. Trichomanes

Trichomanes speciosum (T. radicans). Killarney fern. Raithneach Chill Airne. 6–8. Rhizome covered with black hairs, bearing leaves at wide intervals. Leaves 8–25 cm long, with a long wiry stalk, winged in its upper part. Blade oval-lanceolate in outline, irregularly and repeatedly divided; margins of the ultimate segments untoothed. Sori cylindrical, borne around a bristle-like receptacle, projecting beyond the margins of the flask-shaped indusium; the sporangia eventually fall off, leaving the receptacle as a persistent bristle. Beside waterfalls, in crevices between boulders, under overhanging rocks, on tree trunks and in damp, usually dark, sheltered situations. Formerly widespread, and fairly frequent in the south-west; once almost exterminated by collectors and so now very rare and scattered, from Counties Donegal and Fermanagh south and westwards to Mayo and Kerry with isolated populations in the centre and eastern counties.

Plants form sterile, filamentous gametophytes which produce gemmae; these have established themselves over a wider range than is presently seen in the sporophyte.

8.  MARSILEACEAE

Pilularia globulifera. Pillwort. Lus an phiollaire. 6–9. Rhizome slender, creeping in the mud or on its surface. Leaves narrow, cylindrical, pointed, about 5 cm long, borne singly or in small tufts, curled at the tip when young. Sporangia borne in spherical bodies 3 mm across at the base of the leaves. Spores of two types, borne adjacent to each other: some large (megaspores) others small (microspores). Margins of lakes, pools and slow-moving rivers; very rare and largely confined to the north (possibly extinct around Lough Neagh) and west.

9.  SALVINIACEAE

*Azolla filiculoides. 6–9. A small, floating fern of moss-like habit, with branched stems about 2.5 cm long and slender, unbranched roots. Leaves very small and scale-like, closely overlapping, greenish in summer (especially when shaded), bright red in winter; surface unwettable. Sporangia borne in small spherical structures amongst the leaves; spores of two types megaspores and microspores – the latter aggregated together into a mass. Garden ponds; naturalised in a few places; scattered in the east and south. Native of tropical and subtropical America.

10.  DENNSTAEDTIACEAE

Pteridium aquilinum (Pteris aquilina). Bracken. Raithneach mhór. 7–8. Rhizome underground, extensively creeping. Leaves 50–200 cm high, or even more, with erect stalks and somewhat recurved, oval-triangular blades, thrice-pinnate. Young leaves densely hairy when young; leaves, when mature, often with hairs underneath only. Ultimate segments of leaf narrow-oblong, untoothed, numerous and parallel sided. Sporangia forming continuous sori, just below the leaf-margin, protected by the recurved margin and by an inner membranous indusium. Open woods, mountain slopes, neglected pastures and sandhills; abundant.

11.  PTERIDACEAE

Moderately sized ferns with linear sporangia, which lack a true indusium, but are protected by the rolled-under margins of the leaves.

1. Cryptogramma

Cryptogramma crispa. Parsley fern. Raithneach chas. 6–8. Stem short; leaves tufted, 7–25 cm long. Stem and bases of leaf-stalk clothed with light-brown scales; leaves of two kinds, both irregularly thrice-pinnate with numerous small segments; sterile leaves small, with the ultimate segments broad and overlapping; fertile leaves larger, with the ultimate segments linear-oblong with turned-over margins, not overlapping. Sori small, oval but running together so as to form linear sporangia, near to and covered by the turned-over, lower margin of the leaf. Rocky and stony places, almost exclusively in the mountains of the north and east; extremely rare.

*Matteucia struthiopteris, the Ostrich fern, placed in a separate family, the Onocleaceae, with both long-creeping stolons and an erect, short stem, which often forms a miniature ‘trunk’, producing a crown of leaves at the top and with leaves of two distinct kinds, the outer leaves sterile, up to 1.5 m long and rather like those of Dryopteris filix-mas; the inner smaller and fertile and green at first and later covered with sporangia and entirely brown, with the margin strongly inrolled, is naturalised in marshy ground by Lough Neagh and in County Leitrim and County Mayo, and may become more frequent.

2. Adiantum

Adiantum capillus-veneris. Maidenhair fern. Dúchosach. 6–9. Stem shortly creeping, covered with dark-brown scales. Leaves pale green, usually twice-pinnate, 7–30 cm long; leaf-stalk long, shining black, hairless in the upper parts, with scales at the base. Ultimate segments of leaf fan-shaped, with straight sides and a curved outer margin, which may be untoothed or deeply cut; all on slender, shining black stalks. Sori linear, covered by small, brown flaps of tissue arising from the outer margins of the leaf on the lower side. Rock-crevices and damp rock-faces from Counties Clare to Donegal; locally frequent in the Aran Islands and the Burren district of County Clare, very rare elsewhere and there often an introduction.

12.  ASPLENIACEAE

Asplenium. Spleenwort

Small to medium-sized ferns with short stems and tufted leaves, bearing elongated sori on their underside, protected by a linear, membranous or whitish indusium attached along one side. Stem and lower part of leaf-stalks clothed with narrow, blackish-brown scales; upper part of leaf-stalk usually bare.

1. Asplenium scolopendrium (Phyllitis scolopendrium). Hart’s-tongue. Creamh na muice fia. 7–8. Leaves 20–70 cm long, occasionally more, evergreen, rather firm and leathery, oblong, undivided, bright green; leaf-stalk brownish-purple. Sori lying obliquely (over a vein), in pairs on the underside of the leaves, the members of each pair merging so as to look like one sorus, but each with its own indusium. Woods, hedge-banks, wet areas on walls, and rocky places; very frequent, especially in limestone