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11977 results in Plant sciences

Page 44 of 599

  • 48 - Chenopodiaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 372-422

  • Summary

    Annual or perennial herbs and shrubs. Leaves usually alternate, rarely opposite, sometimes succulent, simple, sessile or petiolate, without stipules. Inflorescence an axillary cyme or panicle, rarely of solitary flowers, sometimes with bracteoles; flowers small and greenish, unisexual or bisexual, semi-inferior or hypogynous, actinomorphic. Perianth green, of one whorl of 1–5 segments, sometimes absent. Stamens 1–5. Styles (1–)2–3; stigmas linear or feathery. Ovary 1-celled with 1 ovule. Fruit a utricle, with an achene enclosed in a pericarp.

    Contains about 100 genera and 15,000 species worldwide.

  • 63 - Violaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 594-610

  • Summary

    Trees, shrubs or herbs. Leaves simple, alternate, usually with stipules. Inflorescence racemose; pedicels with 2 bracteoles; flowers 5-partite, regular or zygomorphic, bisexual, hypogynous, heterochlamydeous; corolla spurred when zygomorphic. Stamens 5, alternate with the petals, the 2 lower ones spurred in zygomorphic flowers; anthers connivent around the ovary, introrse; filaments short; connective often elongated. Style 1, simple, often curved or thickened above; stigma variously developed. Fruit a capsule or berry; endosperm fleshy, copious; embryo straight.

    About 22 genera and 900 species, almost cosmopolitan.

    Viola L.

    Perennial or annual herbs. Leaves alternate; stipules persistent, sometimes leafy. Inflorescence of solitary axillary flowers. Sepals 5, each with an appendage projecting in the opposite direction from it. Petals 5, spreading, unequal, the lowermost larger than the others and spurred or saccate at the base. Stamens 5, subsessile, the lowermost 2 frequently with basal spurs running back into the spur of the lowermost petal; anthers with conspicuous, membranous connectives. Style 1, usually simple, sometimes wanting; stigma terminal, often conspicuously thickened. Fruit a 3-valved, loculicidal capsule, frequently dehiscing explosively; seeds rather large, sometimes with an elaiosome.

    About 400 species, mostly in temperate regions of the northern hemisphere, but in total cosmopolitan.

  • 20 - Blechnaceae

  • from Division 3 - Polypodiophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 49-50

  • Summary

    Perennial herbs with long or short densely scaly rhizomes. Fronds borne in tufts at the ends of rhizome branches, coriaceous, spirally coiled when young, sparsely scaly, of 2 kinds, 1-pinnate with entire pinnae. Sori linear, continuous either side of pinna midrib. Indusia the same shape as the sori and opening towards the midrib. Plants homosporous. Gametophyte green, surface-living.

    Contains 8 genera; cosmopolitan.

  • Fronds pinnate, not producing young plants vegetatively 1. Blechnum

  • Fronds 2-pinnatifid, producing young plants vegetatively on distal part 2. Woodwardia

  • 59 - Malvaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 576-588

  • Summary

    Annual to perennial herbs or shrubs. Leaves alternate, usually palmately veined and often palmate or palmately lobed, usually with stipules which are often caducous. Inflorescence a raceme or small panicle, or flowers solitary and axillary. Flowers bisexual, actinomorphic, hypogynous and sometimes gynomonoecious. Epicalyx usually present, with up to about 13 segments. Calyx with 5 segments or lobes. Petals 5, more or less free, usually pink or purple. Stamens numerous; filaments united into a tube, divided above, with each branch bearing another lobe. Styles as many or rarely twice as many as ovary cells, free or united below. Ovary 5- to manycelled, each cell with 1 to many ovules. Fruit a capsule or a schizocarp that splits into 1- to several-seeded mericarps.

    Contains about 40 genera with around 900 species in temperate to tropical regions.

  • Epicalyx absent 2.

  • Epicalyx present 6.

  • Style branches thread-like, longitudinally stigmatic on inner surface 9. Sidalcea

  • Style branches terminating in capitate stigmas 3.

  • Ovules 2 or more per cell; seeds usually 2 or more per mericarp; mericarps usually dehiscent and releasing the seeds at maturity 10. Abutilon

  • Ovules 1 per cell; seeds 1 per mericarp; mericarps releasing the seed by withering of the wall or by dehiscence at apex 4.

  • Petals blue-violet to lavender or white 12. Anoda

  • Petals white, yellow or orange 5.

  • Petals yellow to orange; mericarps 3–12, each with 2 points 2. Sida

  • Petals white; mericarps 5–15 5. Hoheria

  • Fruit a capsule 13. Hibiscus

  • Fruit a schizocarp 7.

  • Staminal column with 5 teeth at apex; mericarps 5; styles and stigmas 10 14. Pavonia

  • Staminal column bearing filaments at apex; mericarps numerous; styles and stigmas as many as mericarps 8.

  • Epicalyx segments 3–11 9.

  • Epicalyx segments 1–3 10.

  • Staminal tube cylindrical; flowers not more than 3 cm across, at least some of them on conspicuous pedicels 7. Althaea

  • Staminal tube 5-angled; flowers at least 3 cm across, more or less sessile in a spike-like inflorescence 8. Alcea

  • Epicalyx segments united at least at base in bud 6. Malva

  • Epicalyx segments free 11.

  • 9 - Marsileaceae

  • from Division 3 - Polypodiophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 19-20

  • Summary

    Plants heterosporous. Sori enclosed within a sporocarp, which represents a modified, folded pinna with connate margins, each sorus bearing both megasporangia and microsporangia. Sporangia thin-walled, with a vestigial annulus or none. Aquatic or semi-aquatic plants, rooted in the substrate.

    MARSILEACEAE Mirbel

    Perennial herbs with long thin hairy rhizomes. Fronds borne singly but often close together, spirally coiled when young, of two kinds, sterile and fertile, the sterile ones filiform, the fertile ones small, globose and shortly stalked. Sporangia borne in globose or ovoid-oblong, hard, hairy sporocarps at the base of the stipe, each sporocarp containing two or more sori, each of which is surrounded by an indusium; the sporangia of two kinds, both occurring in the same sorus, the microsporangia above the megasporangia, developing in regular sequence from the apex to the base of the sorus, the microsporangia with numerous microspores, the megasporangia with one megaspore. Male prothallus of two vegetative cells and two antheridia, each producing 16 multiciliate spermatozoids. Female prothallus with many vegetative cells and a single archegonium situated on a projection from the megaspore.

    Contains 3 genera and about 73 species, cosmopolitan

  • 42 - Myricaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 317-318

  • Summary

    Deciduous, monoecious or dioecious trees. Leaves alternate, simple, dotted with resinous glands, aromatic, without stipules. Flowers unisexual. Male flowers solitary in the axils of bracts and forming catkins, without a perianth or bracteoles; stamens 2–16; filaments free or united below. Female flowers with a bract and 2 or more bracteoles; style short; stigmas 2, filiform. Ovary 1-celled; ovule one. Fruit a drupe or nut; embryo straight; seeds without endosperm.

    Consists of 3 genera and about 50 species, cosmopolitan.

    Myrica L.

    Deciduous, usually dioecious shrubs, but plants may change sex from year to year. Leaves alternate, strongly aromatic, without stipules. Flowers unisexual, in catkins, solitary in the axil of a bract. Male flowers solitary in the axils of bracts and forming catkins, without a perianth or bracteoles. Female flowers with a bract and 2 bracteoles. Fruit a drupe or nut.

    Contains about 35 species, cosmopolitan except for central and southern Europe, North Africa, south-west Asia and Australia.

  • 46A - Nyctaginaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 365-366

  • Summary

    Herbs, trees and shrubs, sometimes tuberous. Leaves opposite, without stipules. Inflorescence variable. Flowers bisexual or unisexual, actinomorphic, with a pedicel; sometimes each flower with an involucre. Corolla with the basal part persistent and enclosing the receptacle, often accrescent and forming an anthocarp, with the apical part usually circumscissile and caducous. Stamens 1–40, connate at base. Style 1, terminal. Fruit an indehiscent anthocarp.

    Contains 30 genera and some 290 species, mostly tropical and especially American.

    Mirabilis L.

    Perennial herbs with root tubers. Leaves opposite. Inflorescence a terminal corymb, 1- to many-flowered; each flower with a persistent, accrescent involucre divided halfway into 5 lobes. Flowers bisexual, trumpet-shaped; the large tube with a constriction above the basal part and the lower part of the tube ribbed or with knobs, the upper part and the limb circumscissile and caducous after anthesis. Stamens 3–6, unequal, distinctly exserted. Style 1, distinctly exserted. Ovary sessile. Fruit an anthocarp formed by the basal part of the corolla being persistent and enclosing the receptacle and often accrescent.

    Contains about 60 species in the Americas.

  • 64 - Tamaricaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 610-610

  • Summary

    Shrubs or small trees. Leaves alternate, simple, usually ericoid. Inflorescence a raceme, actinomorphic, bisexual. Sepals 4–5, free or slightly connate at base. Petals 4–5, free. Stamens 4 to numerous, free or partly united. Ovary superior, of 3–5 carpels. Fruit a septicidal capsule; seeds numerous, with numerous long unicellular hairs.

    Contains 4 genera and about 120 species mainly in the Mediterranean region and central Asia, extending to eastern Asia, South Africa and western Europe.

    Tamarix L.

    Deciduous shrubs or small trees; the smaller twigs falling with the leaves. Leaves alternate, simple, usually ericoid, without stipules. Inflorescences of catkin-like racemes; flowers hypogynous, bisexual, bracteate. Sepals 4–5. Petals 4–5, without ligules. Stamens 5, free or nearly so, inserted around a nectariferous disc; anthers extrorse. Styles 3, short and thick. Fruit a capsule; seeds with a sessile tuft of hairs at apex; endosperm absent.

    Contains over 50 species, mainly in the eastern Mediterranean, extending to central and east Asia, South Africa and western Europe.

    There are old records for T. chinensis Lour. and T. parviflora DC

  • 5 - Ophioglossaceae

  • from Division 3 - Polypodiophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 14-16

  • Summary

    Perennial herbs with a short or corm-like rhizome, without scales and with fleshy roots. Fronds borne singly, with an erect stem-like stipe and a sterile lamina, often with one fertile lamina. Sterile lamina simple or entire or 1-pinnate, not spirally coiled when young. Fertile lamina a simple spike or a panicle, with the spike or panicle-branches bearing sporangia in a row either side of the axis. Sporangia homosporous. Prothallus subterranean, massive, without chlorophyll but with endotrophic mycorrhizae, bearing organs of both sexes, with the antheridia sunk in the tissues.

  • 21A - Ginkgoaceae

  • from Division 4 - Pinophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 54-54

  • Summary

    Deciduous dioecious trees with resinous and slightly mucilaginous wood. Leaves spirally arranged, distant on long shoots, more crowded and clustered on short lateral spur shoots; lamina flattened and broadly fan-shaped, bilobed or entire, without midribs but with numerous fine, radiating, dichotomously branched veins, petiolate. Male and female strobili on different trees. Male strobili catkin- like, in small groups of about 4–8 in the axils of the leaves or scale-leaves at the ends of the short spur shoots, among and emerging with or before the foliage leaves and soon deciduous; pollen wind-borne, without air-bladders; fertilisation by motile spermatozoids. Female strobili drupe-like, in the axils of leaves or scale-leaves in sparse groups at the apices of short shoots among the leaves, each long-stalked with two distal terminal ovules of which only one develops. Cones fleshy, orange-yellow, slightly glaucous at maturity, ellipsoid-globose, with the outer layer pulpy and odoriferous, surrounding an inner stony one.

    Contains a single genus, native in China.

  • 22 - Pinaceae

  • from Division 4 - Pinophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 54-95

  • Summary

    Monoecious trees or shrubs, usually evergreen, sometimes deciduous. Leaves usually spirally arranged, sometimes appearing to be two-ranked or sometimes in tufts, needle- like. Male strobili cylindrical; microsporophylls with 2 microsporangia; pollen grains usually with 2 bladder-like wings. Cones conical or oblong, maturing in 1–2 years, usually large, erect or hanging; scales numerous, spirally arranged, woody, separated from the bracts, each bearing 2 inverted ovules. Seeds usually with one long wing projecting backwards. Cotyledons several to many.

    Consists of 9 genera containing about 190 species mainly confined to temperate regions of the northern hemisphere.

  • Leaves deciduous 2.

  • Leaves evergreen 3.

  • Mature female cones remaining whole and falling intact 5. Larix

  • Mature female cones dismembering on tree 6. Pseudolarix

  • Leaves united in groups of usually 2, 3 or 5 by sheaths at the base 8. Pinus

  • Leaves not united in groups 4.

  • Leaves distant on long shoots and more clustered on short side shoots 7. Cedrus

  • Leaves all distant on long shoots; side shoots absent 5.

  • Shoots roughened after leaf abscission by persistent leafbases 6.

  • Shoots more or less smooth; leaf-bases not persistent 7.

  • Leaves shortly and distinctly petiolate, never pungent 3. Tsuga

  • Leaves sessile, mostly pointed and usually pungent 4. Picea

  • Winter buds ovoid, obtuse at apex; female cones erec 1. Abies

  • Winter buds spindle-shaped, acute at apex; female cones pendulous or variously orientated 2. Pseudotsuga

  • 39 - Moraceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 308-310

  • Summary

    Trees, shrubs and climbers, lactiferous. Leaves usually alternate. Inflorescence axillary, variable, monoecious or dioecious; flowers small, unisexual. Perianth usually 4-lobed. Male flower with 2 or 4 stamens, rudimentary ovary sometimes present. Female flower with ovary superior or inferior, usually 1-locular; styles usually 2, filiform. Fruit usually drupaceous; seeds with or without endosperm.

    Contains 53 genera with about 1400 species in mainly tropical and temperate regions, much cultivated.

  • Fruit of numerous drupelets crowded into a syncarp 1. Morus

  • Fruit a syconium, soft and fleshy, containing numerous achenes 2. Ficus

    • Morus L.

    Deciduous, monoecious or dioecious trees. Buds with 3–6 scales. Leaves dentate or lobed; stipules caducous. Inflorescence an axillary spike; flowers unisexual. Male flowers with 4-lobed perianth and 4 stamens, sometimes with a rudimentary ovary. Female flowers with a 4-lobed perianth and a style with 2 branches. Ovary 1- or 2-locular, superior. Fruit of numerous drupelets crowded into a syncarp.

    Contains about 12 species in temperate and subtropical regions of the northern hemisphere.

  • 1 - Lycopodiaceae

  • from Division 1 - Lycopodiophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 2-5

  • Summary

    Perennial herbs. Stems elongated, not, little or considerably branched, bearing roots. Leaves small, simple, bearing 1 vein, without ligule. Homosporous. Sporangia in leaf axils, all alike, borne near the base of the upper surface of the leaves, which vary from being like stem leaves and arranged among them to being strongly differentiated from the stem leaves and arranged in terminal cones, unilocular, compressed, dehiscing by splitting, with numerous spores. Gametophyte subterranean, saprophytic and with mycorrhizae; antheridia in the centre of the apical part of the gametophyte, containing biciliate spermatozoids; archegonia in a ring around the antheridia.

    Contains six to eight genera in temperate and tropical regions.

  • Stems ascending, divided dichotomously into branches of equal length; sporangia axillary 1. Huperzia

  • Stems creeping and rooted, with short lateral branches; sporangia in terminal cones 2.

  • Leaves 4-ranked, opposite and decussate; branches more or less flattened 4. Diphasiastrum

  • Leaves in whorls, alternate or spiral; branches not flattened 3.

  • Stem leaves and sporangium-bearing leaves similar, without either hair points or scarious margins 2. Lycopodiella

  • Either stem leaves with hair points or sporangium-bearing leaves with scarious toothed margins

  • Introduction

  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp xxvi-liv

  • Summary

    Taxonomy and nomenclature are the most important branches of every science and for that matter everything we do. Get it wrong and a surgeon could operate on a lung instead of a kidney, or a shopper could buy arsenic instead of sugar. Most of us are very bad with names and scientists are no exception. Some of us get better at our particular subject but remain slapdash about all associated subjects. Ecologists develop a broad range of knowledge but sometimes their knowledge of taxonomy is not precise enough to explain the subtleties of why one variant is in a particular place but not another or why a particular insect only visits a particular variant of a plant. Television shows us some wonderful documentary films on nature and describes in great detail the birds and animals but hardly mentions a plant and, when it does, often gets it wrong. It is infuriating for someone interested in both plants and poetry to hear Wordsworth's famous poem on Daffodils quoted and then to be shown an image of the cultivated ‘February Gold’ which has nothing to do with the Daffodil of the Lakes. When P. D. S. sat on conservation bodies in Cambridge he was always supported by the late John Smart, an entomologist, because Smart said that if the botany is all right it is all right for the insects.

    HISTORICAL BACKGROUND OF OUR FLORA

    The first real flora of these islands was John Ray's Catalogus plantarum Angliae, et Insularum adjacentium in 1670. The first flora to use the Linnaean binomial system of nomenclature was William Hudson's Flora Anglica nearly a hundred years later in 1762. This was followed in 1776 by William Withering's A botanical arrangement of all the vegetables naturally growing in Great Britain, the first of many floras written primarily for the amateur.

    James Sowerby's English botany, the text of which was written by J. E. Smith, was first published between 1790 and 1814. It presented for the first time a complete set of coloured illustrations of our plants, illustrations which are still unsurpassed for line and colour. The third edition, published between 1863 and 1886, has inferior illustrations, but its text, rewritten by James Boswell Syme, is still important for its nomenclature and infraspecific taxa.

  • 56 - Elatinaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 560-560

  • Summary

    Small, more or less aquatic annuals or rarely perennials. Leaves opposite, simple, entire, more or less petiolate, with stipules. Flowers minute, solitary in leaf axils, bisexual, hypogynous, actinomorphic. Sepals 3–4, membranous, free or united at base. Petals 3–4, free. Stamens 6 or 8. Styles 3 or 4, very short; stigmas capitate. Ovary 3- to 4-celled, each with numerous ovules on axile placentation. Fruit a 3- to 4-celled capsule.

    Contains 2 genera and about 40 species; cosmopolitan.

    Elatine L.

    Annual or perennial herbs in wet places. Leaves opposite, simple, entire, with stipules. Flowers minute, solitary in leaf axils or in cymes, bisexual, hypogynous, actinomorphic. Sepals 3–4. Petals 3–4, reddish or pinkish-white. Stamens 6 or 8. Styles 3 or 4; stigmas capitate. Fruit a 3- to 4-celled capsule.

  • 45 - Corylaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 355-364

  • Summary

    Deciduous, monoecious trees or shrubs. Buds with scales. Leaves alternate, simple; stipules caducous. Flowers in unisexual anemophilous catkins. Male catkins pendulous, with one flower in the axil of each bract; bracteoles 2, united with the bract, or absent; perianth absent; stamens 3–14. Female catkins of 2 flowers in the axil of each bract; bracteoles present; perianth small, irregularly lobed; ovary with 2 loculi, inferior; styles 2. Fruit a nut, subtended or surrounded by an involucre formed from the accrescent bract and bracteoles.

    Contains 4 genera and over 50 species in north temperate regions and central America.

  • Buds ovoid, obtuse at apex; leaves usually with 5–12 pairs of veins; fruits in clusters of 1–10 3. Corylus

  • Buds fusiform to ovoid, acute at apex; leaves with 9 or more pairs of veins; fruits numerous, in pendulous spikes 2.

  • Bark grey, generally smooth; male catkins appearing in spring; nuts subtended by a 3-lobed or serrate involucre 1. Carpinus

  • Bark becoming scaly and rough; male catkins visible throughout the winter; nuts enclosed in an entire, bladder-like, apiculate involucre 2. Ostrya

    • Carpinus L.

    Deciduous, monoecious trees or shrubs. Bark grey, smooth. Buds fusiform or ovoid, acute at apex. Leaves alternate, with 9 or more pairs of veins, simple; stipules caducous. Flowers in unisexual catkins. Male catkins pendulous; one flower in the axil of each bract, without bracteoles; perianth absent; stamens about 10, with bifid filaments. Female catkins pendulous and spike-like, with 2 flowers in the axil of each bract; each bract accompanied by 6 bracteoles; flowers with the perianth small and irregularly lobed; ovary with 2 loculi; styles 2. Fruit a nut, subtended by a lobed or serrate, strongly veined involucre.

    Contains over 25 species in the north temperate regions and central America.

  • 30 - Nymphaeaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 129-132

  • Summary

    Perennial water or marsh plants usually with stout, creeping rhizomes. Leaves floating, submerged or aerial; floating leaves peltate or cordate, usually long-petioled; submerged leaves simple, thin and translucent. Flowers solitary, terminal, generally floating, bisexual, actinomorphic, hypogynous to epigynous, the parts variously arranged. Perianth usually differentiated into 3–6 green sepals and 3 to many petals which may pass gradually into the usually numerous stamens with introrse anthers and are either hypogynous or inserted at various heights on the wall of the more or less inferior ovary. Carpels 8 or more, either free, but then sunk in the receptacle, or united and superior or united into a many-celled ovary and inferior. Ovules 1–many, inserted over the inner walls of the carpels. Fruit a group of achenes sunk in the receptacle or a spongy capsule dehiscing regularly or irregularly by the swelling of internal mucilage; seeds often with arils, with or without endosperm, sometimes with perisperm as well as endosperm.

    Contains about 3 genera with some 75 species, cosmopolitan.

  • Flowers white, rarely red; ovary semi-inferior 1. Nymphaea

  • Flowers deep yellow; ovary superior 2. Nuphar

    • Nymphaea L. nom. conserv.

    Castalia Salisb.

    Perennial herbs with stout rhizomes. Leaves more or less subrotund, rarely peltate, with stipules. Flowers usually floating, often large and showy. Sepals (3–)4(–5), green, hypogynous. Petals numerous, inserted at successively higher levels on the side of the half-inferior ovary, the outermost much longer than the sepals, the innermost shorter and narrower and grading into the stamens. Stamens numerous, the outer with broad, petaloid filaments, all inserted towards the top of the ovary. Nectaries absent. Ovary syncarpous, many-celled with numerous ovules in each cell, concave above with a boss at the centre from which the stigmatic surfaces radiate. Fruit a spongy, berry-like capsule, splitting by the swelling of internal mucilage to release the seeds, which float because of the air-containing aril and seed wall.

  • 15 - Thelypteridaceae

  • from Division 3 - Polypodiophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 26-28

  • Summary

    Perennial herbs with a long and slender or short and thick rhizome with scales. Fronds borne singly or in dense terminal tufts, with sparse or very sparse scales, spirally coiled when young, of one or two kinds, almost 2-pinnate, with entire to crenate or sinuate pinnules. Sori in a row on underside of pinnule, usually near the margin. Indusia absent or small, thin and soon withering. Plants homosporous. Gametophyte green, surface-living.

  • 44 - Betulaceae

  • from Division 5 - Magnoliophyta
  • Peter Sell, University of Cambridge, Gina Murrell, University of Cambridge
  • Book:
    Flora of Great Britain and Ireland
    Print publication:
    12 April 2018, pp 333-355

  • Summary

    Leaves alternate, simple; stipules caducous. Male flowers in pendulous catkins, 3 together in a dichasium in the axil of each bract; bracteoles 2 to 4 to each group of flowers; perianth present. Female flowers in erect cylindrical or ovoid catkins, 2 or 3 together in a dichasium in the axil of each bract; bracteoles 2 to 4 to each group of flowers; perianth absent; ovary 2-celled; ovule one in each cell, anatropous, pendulous; styles 2, free. Fruit a flattened nut, single or in a group of 2 or 3 on the surface of a scale formed from the accrescent fused bract and bracteoles, in a dense cylindrical or cone-like strobilus; seed 1, endosperm absent.

    Contains 2 genera and about 95 species in north temperate regions and tropical mountains; central Andes.

  • Flowers opening with the leaves; stamens 2, bifid below the anthers; fruiting strobili cylindrical, with 3-lobed scales, falling with the nuts 1. Betula

  • Flowers opening before the leaves; stamens 4, entire; fruiting strobili cone-like, with 5-lobed persistent scales 2. Alnus

    • Betula L.

    Deciduous, monoecious trees and shrubs. Trunk slender and extending well into the crown. Bark smooth and resinous, marked by long longitudinal lenticels, often separating into thin papery plates, often becoming thick, deeply furrowed and scaly at the base of old trunks. Twigs roughened by crowded leaf-scars of many years; young shoots clothed with varying amounts of lenticels, or lenticels absent; simple eglandular hairs or peltate glands are often diagnostic. Buds with numerous scales, which are fully grown and bright green at midsummer. Leaves usually alternate, sometimes in pairs or threes on short shoots, sometimes incised-lobed; stipules scarious and usually caducous. Male and female flowers in 3-flowered dichasia, arranged spirally in separate catkins, with the lateral flowers of the dichasium subtended by bracteoles adnate to the base of the scale. Male catkins long and pendulous, solitary or clustered, appearing in summer or autumn in the axils of the last leaves of a young shoot and near the ends of short lateral twigs, erect and naked during the winter; scales in the spring broadly ovate, rounded, short-stalked, yellow or orange below the middle and dark chestnut-brown above; flowers with a membranous 4-lobed calyx, often 2-lobed by suppression, with the anterior lobe obovate, rounded at the apex, much longer than the minute posterior lobe; the 2 bifid stamens inserted at the base of the calyx.

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