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11777 results in Plant sciences

Page 33 of 589

  • 24 - Cupressaceae

  • 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 100-112

  • Summary

    Monoecious or dioecious, evergreen, resinous trees or shrubs. Juvenile leaves, when present, needle-like and spirally arranged. Adult leaves small, usually scale-like, adpressed, in decussate pairs, or sometimes in threes. Male strobili globose or oblong, with relatively few, decussate microsporophylls bearing 3–5 microsporangia on lower surface; pollen grains often rounded. Cones globose or ovoid and erect, maturing in 1 to 2 years, relatively small; seed-scales relatively few, woody or somewhat fleshy and coalescent, completely adnate to the subtending bract, bearing 2 to many erect ovules on the upper surface. Seeds winged or not. Cotyledons 2–4, relatively small.

    Contains about 125 species in 20 genera, 9 of which are monotypic. Occurs throughout the major land masses except the Arctic and Antarctic and on many of the islands. Many species are cultivated for ornament.

    There is much disagreement over the taxonomy of the genera in this family, particularly between European and American schools of thought. We have not brought it up to date. We have, however, added all the new names so that users can choose the names they wish. Those who wish to work it out for themselves should read the following.

  • 43 - Fagaceae

  • 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 318-333

  • Summary

    Deciduous or evergreen, monoecious trees. Leaves alternate, simple, petiolate, with stipules at least when young. Male flowers in pendulous or stiff catkins or one to numerous in capitula; stamens 4–40. Female flowers in small groups of one to few, surrounded by numerous small scales; ovary 3- or 6-celled, with 2 ovules per cell; styles 3–9; stigmas linear. Fruit a cupule formed from the fused scales, containing 1–3(–6) nuts.

    Contains 8 genera and about 900 species, worldwide but absent from tropical and South Africa and east tropical South America.

  • Buds pointed at apex; male flowers one to many in short heads; nuts sharply 3-angled 2.

  • Buds rounded at apex; male flowers in long catkins; nuts terete or with rounded angles 3.

  • Male flowers numerous, pendulous; nuts 2 per cupule 1. Fagus

  • Male flowers 1–3 in stiff clusters; nuts 3 per cupule 2. Nothofagus

  • Male flowers in stiff catkins; cupules strongly spiny, completely enclosing 1–3 nuts 3. Castanea

  • Male flowers in pendulous catkins; cupules not spiny, enclosing only lower part of 1 nut 4. Quercus

    • Deciduous, monoecious trees. Buds fusiform, acute at apex. Leaves alternate. Male flowers in tassel-like heads on a long pendulous peduncle; perianth campanulate, 4- to 7-lobed; stamens 8–16. Female flowers usually paired, surrounded below by long scales; styles 3, long. Fruit a cupule covered with projecting scales or prickles, 4-valved, woody, containing 1 or 2 triquetrous nuts. Germination epigeal.

    Contains 10 species in north temperate regions and Mexico.

  • Preface and acknowledgements

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

  • Summary

    For 70 years I have worked in the Herbarium at Cambridge University on the British and European floras. I have collected, often with Gina's company, about 30,000 numbers consisting of some 50,000 specimens from most parts of the British Isles and made many visits to Continental Europe. Particular attention has been given to most critical genera: Cerastium, Chenopodium, Conyza, Crepis, Dactylorhiza, Euphrasia, Fumaria, Hieracium, Limonium, Polygonum, Pilosella, Prunus, Rhinanthus, Rumex, Salicornia, Salix, Scleranthus, Sorbus and Ulmus. In helping friends in various ways I have also considered the taxonomy of Alchemilla, Ranunculus subgenus Batrachium, Potamogeton, Rubus and Taraxacum. I have also spent much time studying ecotypic and geographical variation, in particular comparing those variants which occur on the coasts in dunes, shingle and saltmarsh with those growing as arable weeds and with those in mountains. Special attention has also been given to trees and shrubs.

    It had long been my wish to publish this information in a critical flora of Great Britain and Ireland. In the 1970s a group of us tried to get a grant to carry this out, but we were unsuccessful. Clive Stace then started work on his New Flora of the British Isles, which was first published in 1991, with a second edition in 1997 and a third in 2010. In it he gives only short descriptions and omits most of the species in the large apomictic genera and many of the infraspecific variants whose differences are not apparent in his abbreviated diagnoses. Numerous introduced species are included by Stace in a British and Irish flora for the first time, detailed descriptions and specimens of many of which have previously been difficult to find. Stace's flora is to my mind an excellent field guide, which it would be difficult to better, but it does not give the detailed descriptions that are needed to confirm the identification of a plant which is new to you. A good description in my opinion is one in which a picture of the plant unfolds before you as you read it and includes as much of the variation as possible.

  • 25 - Araucariaceae

  • 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 112-113

  • Summary

    Dioecious or monoecious, evergreen, resinous trees. Leaves spirally arranged, broad and flat, many-veined. Male strobili large, cylindrical; microsporophylls with 5–15 pendulous microsporangia; pollen grains wingless. Cones subglobose to ovoid, maturing in 2 to 3 years, rather large, erect; scales with large, fused, woody bracts, each bearing one inverted ovule. Seeds adnate to the bract and falling with it.

    Contains three genera and 40 species in South America, Malaysia, Indonesia and the Philippines to Australasia.

    Araucaria Juss.

    Columbea Salisb. nom. illegit.

    Dioecious, rarely monoecious, evergreen, resinous trees. Branches regularly whorled. Buds inconspicuous. Leaves spirally arranged, usually scale-like. Male strobili terminal, solitary or in clusters. Cones large, subglobose or ovoid, ripening in 2 to 3 years; scales breaking apart from the central axis at maturity; ovules one per scale to which they are united. Seeds usually winged at margin.

    Contains 19 species, found in southern Brazil, southern Chile, south-west Argentina, Australia, New Caledonia and New Guinea.

  • Kingdom 1 - Plantae

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

  • Summary

    An aquatic multicellular green alga was probably the ancestor of all land plants, but these became less dependent on external water for reproduction as their conducting tissue, cuticle, stomata and seeds evolved. Their photosynthetic pigments (chlorophyll and carotenoids), their chief storage product of starch and their cellulose-rich cell walls all provide evidence for this origin. Plants have a life cycle with an alternation of generations in which haploid gametophytes alternate with diploid sporophytes. Spores resulting asexually from meiosis in sporophytes grow into gametophytes, which produce male and female cells for sexual reproduction.

    The oldest fossils of land plants date from the Silurian period, somewhat over 400 million years ago.

  • 28A - Saururaceae

  • 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 127-128

  • Summary

    Rhizomatous, herbaceous marsh plants. Leaves alternate, simple, entire, cordate, petiolate, stipulate. Inflorescence a terminal spike, with 4–6 perianth-like bracts at base. Flowers bisexual, hypogynous, actinomorphic; perianth absent. Stamens 3(–4) borne on base of ovary. Styles 3 curved back; stigma capitate to punctiform. Ovary 1-celled, with parietal placentation, with rather few ovules. Fruit a capsule, the 3 valves opening only distally.

    Consists of 5 genera and only 7 species.

  • 12 - Cyatheaceae

  • 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 23-23

  • Summary

    Tree ferns. Fronds usually very large, pinnately compound, borne on a well-developed trunk; veins free. Sori superficial, dorsal. Indusia globose, at first covering the sori, finally splitting into lobes, or incomplete. Spores tetrahedral, without perispore.

    Cyathea Sm.

    Large, tree-like, terrestrial ferns, with an erect rhizome, tall and trunk-forming. Fronds forming large, spreading crowns at the apex of the trunk. Fronds all of one kind, very large and several times pinnately divided to produce a lace-like effect. Sori rounded, large. Indusia cup-shaped.

    Contains several hundred species occurring in the tropics and subtropics of both the Old and New Worlds.

  • 46 - Phytolaccaceae

  • 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 365-365

  • Summary

    Perennial herbs, more or less woody at the base. Leaves alternate, simple, entire, petiolate, without stipules. Inflorescence a numerous-flowered, leaf-opposed raceme; flowers bisexual, hypogynous and actinomorphic. Perianth of one whorl of 5 free segments, usually petaloid. Carpels 6–10 in one whorl, more or less free to fused, each with one ovule. Stamens 7–16. Style 1, short. Fruits succulent, berry-like, 6–10-lobed from close adherence or fusion of the carpels.

    Contains about 20 genera and over 125 species. Tropical and subtropical regions, especially of the New World. There has been much confusion about the identity of plants occurring in Great Britain, which have usually been called P. acinosa Roxb., so in most cases only occurrences in and around Cambridge are mentioned below.

  • 67 - Salicaceae

  • 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 616-670

  • Summary

    Deciduous, dioecious (or rarely monoecious) trees or shrubs. Leaves alternate, simple, usually with stipules. Flowers in catkins, each flower solitary in the axil of a bract (here called a scale or catkin-scale). Perianth absent or very small, but flowers of both sexes usually with a cup-like disc or 1 or 2 small nectaries at base. Stamens 2 to many; filaments long and slender, occasionally connate. Ovaries of 2 carpels, 1-celled, with 2 or 4 parietal placentae. Style 1 or rarely 2; stigmas 2, often bifid. Fruit a 2- to 4-valved capsule; seeds enveloped by long silky hairs arising from the funicle; endosperm absent; embryo straight.

    Contains 3 genera, the third, Chosenia, with a single species in north-east Asia.

  • Stems almost always monopodial, with a terminal bud; buds with several imbricate outer scales; leaves usually broad, commonly ovate and more or less cordate; catkin-scales toothed or laciniate; stamens numerous; flowers with a cuplike disc, wind-pollinated 1. Populus

  • Stems sympodial, lacking a terminal bud; buds with one hooded outer scale (very rarely more); leaves usually narrow, simple, entire or toothed; catkin-scales generally entire; stamens usually 2 (sometimes up to 12); flowers with 1–2 (rarely more) nectaries, without a disc, usually insectpollinated 2. Salix

    • Populus L.

    Deciduous, almost always dioecious trees with soft, light wood and monopodial branching. Buds with several imbricate outer scales, often viscid and balsam-scented; terminal bud usually present. Leaves alternate, usually broad, commonly ovate and more or less cordate at base; petiole long, often strongly compressed laterally; stipules generally inconspicuous and caducous. Inflorescence usually without foliaceous bracts; flowers opening before the leaves, in pendulous catkins, wind-pollinated; catkin-scales toothed or laciniate; each flower with a cup-like disc. Stamens of male catkins 4 to many, with short filaments; anthers red or purple. Ovaries of female catkins with 2–4 carpels; style 1; stigmas 2, sessile or subsessile, frequently dilated apically. Capsules 2- to 4-valved; valves sometimes suberect or indistinctly recurved at maturity.

  • 52 - Caryophyllaceae

  • 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 434-486

  • Summary

    Herbs, sometimes woody at the base, or more rarely shrubs. Leaves usually opposite, more rarely alternate or verticillate, simple, entire, with or without stipules. Inflorescence an often bracteate dichasium; flowers usually bisexual, actinomorphic. Sepals 4 or 5, free or fused and often united by scarious strips of tissue (commissures) alternating with the calyx teeth. Petals (0–)4 or 5, free. Stamens usually 8–10, obdiplostemonous. Stigmas (1–)2– 5. Ovary superior, unilocular at least above, with one to numerous campylotropous ovules on a basal or free-central placenta. Fruit usually a capsule, dehiscent, with teeth equalling the styles in number or twice as many, or more rarely a berry or achene.

    Contains about 1750 species in 70 genera, mainly in temperate regions of the northern hemisphere.

  • Stipules present, though sometimes caducous 2.

  • Stipules absent 10.

  • All leaves alternate 3.

  • Leaves opposite or verticillate (or some leaves apparently alternate) 4.

  • Sepals less than 3 mm; fruit an achene 12. Corrigiola

  • Sepals 3–7 mm; fruit a capsule 13. Telephium

  • Styles 1 or 2 5.

  • Styles 3 or 5 8.

  • Bracts conspicuous, longer than flowers 14. Paronychia

  • Bracts inconspicuous, shorter than flowers 6.

  • Plant erect; leaves aristate 14. Paronychia

  • Plant procumbent; leaves not aristate 7.

  • Sepals not white and spongy 15. Herniaria

  • Sepals conspicuously white and spongy 16. Illecebrum

  • Leaves obovate or subrotund 17. Polycarpon

  • Leaves subulate, linear or linear-lanceolate 9.

  • Stipules not connate; styles 5 18. Spergula

  • Stipules connate; styles 3 19. Spergularia

  • Sepals free or joined only at the base 11.

  • Sepals joined to form a distinct calyx tube 26.

  • Styles 2 12.

  • Styles 3–5 14.

  • Petals absent; fruit indehiscent 11. Scleranthus

  • 38 - Cannabaceae

  • 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 306-308

  • Summary

    Annual or perennial, usually dioecious herbs. Leaves alternate or opposite, palmately lobed to more or less palmate, with stipules. Flowers small and inconspicuous, hypogynous, actinomorphic. Perianth small to more or less absent, of one whorl of 5, completely or partly, fused segments. Male flowers with 5 stamens. Female flowers with a 1-celled ovary with 1 ovule and 2 styles. Fruit an achene subtended by a persistent bract.

    Contains 2 genera with 3 species in the northern hemisphere, which are much cultivated.

  • Erect annual; at least the upper leaves alternate 1. Cannabis

  • Rampant perennial climber; leaves all opposite 2. Humulus

    • Cannabis L.

    Like family.

    Contains one species native in south and west Asia but cultivated and naturalised widely elsewhere.

  • 31 - Ceratophyllaceae

  • 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 133-134

  • Summary

    Submerged aquatic perennial herbs. Leaves in whorls of (3–)6–8(–12), regularly forked into linear segments; without stipules. Flowers solitary in leaf axils, male and female at different nodes, monoecious, actinomorphic, hypogynous, sessile. Perianth segments numerous, free, green, narrow, in one whorl. Male flowers with 10–25 stamens. Female flowers with a 1-celled ovary with 1 ovule. Style 1; stigma minutely bifid. Fruit an achene.

    Contains one genus and about 10 species, cosmopolitan.

  • 57 - Hypericaceae

  • 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 560-572

  • Summary

    Shrubs or herbs, with translucent glands containing essential oils and sometimes red or black glands containing hypericin. Leaves simple, opposite or rarely in whorls of 3–4; petiole absent or very short, without stipules. Inflorescence of solitary flowers or in terminal cymes; flowers actinomorphic, bisexual, hypogynous. Sepals 5, free, often glandular. Petals 5, free, yellow, often glandular. Stamens numerous, usually partially fused into 3–5 fascicles. Styles 3 or 5; stigmas capitate. Fruit a capsule or becoming succulent and berry-like.

    Hypericum L.

    Herbs or shrubs. Leaves sessile or nearly so. Flowers usually without nectar. Sepals 5. Petals 5, yellow, generally very oblique. Stamens numerous, often more or less connate in bundles; anthers versatile. Styles 3 or 5, free or connate; stigmas capitate. Ovary 1-celled, with 3 or 5 parietal placentae, or 3- or 5-celled with axile placentae. Fruit a capsule or becoming succulent and berry-like.

    Contains over 400 species in temperate zones and on mountains in the tropics.

  • 49 - Amaranthaceae

  • 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 422-430

  • Summary

    Annual to perennial herbs. Leaves alternate, simple, entire; the lower petiolate; without stipules. Inflorescence usually of axillary cymes or flowers densely clustered at stem apex; flowers small and usually brownish, mostly unisexual, hypogynous, actinomorphic. Perianth scarious, of 1 whorl of usually (2–)3–5 free segments, sometimes absent. Stamens as many as perianth segments. Styles 2–3; stigma linear. Ovary 1-celled, with 1 ovule. Fruit an achene or more usually a capsule, often 1-seeded.

    Contains about 65 genera and about 850 species, mainly in tropical and warm temperate regions.

    Carolin, R. C. (1933). The trichomes of the Chenopodiaceae and Amaranthaceae. Bot. Jahrb. 103 : 451–466.

  • Perianth segments coloured red, lilac, yellow or silvery, much longer than the bracts 1. Celosia

  • Perianth segments colourless to greenish-brown or sometimes red, but then not longer than the bracts 2. Amaranthus

    • Celosia L.

    Annual herbs. Leaves alternate. Inflorescence terminal on stem and branches; bracteoles 3. Perianth segments 5, oblong, acute or obtuse. Stamens 5; filaments connate below in a membranous tube. Style 1, long and filiform. Fruit a circumscissile capsule; seeds numerous.

  • 32 - Ranunculaceae

  • 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 134-225

  • Summary

    Annual to perennial herbs or woody climbers. Leaves spirally arranged, alternate or sometimes opposite or whorled, simple, often palmately lobed to repeatedly and finely palmatisect or pinnatisect, usually without stipules. Inflorescence terminal or flowers solitary; flowers bisexual, hypogynous, usually actinomorphic, rarely zygomorphic. Perianth segments can be sepaloid or petaloid and nectariferous, but each genus should be consulted to see how many segments are present and what form they take. Stamens numerous. Carpels 1 to many. Fruit usually an achene or follicle, rarely a berry or capsule.

    Contains about 50 genera and 1900 species.

  • Plants usually woody and climbing; leaves opposite or rarely absent 13. Clematis

  • Plants usually herbaceous and usually not climbing; leaves alternate or all basal, sometimes with a whorl of bracts below the flowers which can be mistaken for leaves 2.

  • Fruit of one or more follicles 3.

  • Fruit a group of achenes or berry-like 12.

  • Flowers bilaterally symmetric 4.

  • Flowers radially symmetric 6.

  • Ovary of one carpel; follicle one 7. Consolida

  • Ovary of 2 or more carpels; follicles 2 or more 5.

  • Upper perianth segments hooded or helmet-like 6. Aconitum

  • Upper perianth segments with a spur 8. Delphinium

  • Perianth of a single whorl of segments, the nectaries in small depressions near the carpels 1. Caltha

  • Perianth of 2 whorls of segments, i.e. the perianth and nectaries 7.

  • Petals or petaloid nectaries as large as or larger than perianth segments 17. Aquilegia

  • Petals or petaloid nectaries smaller than the perianth segments, if as long or longer then narrower 8.

  • Flowering stems leafless but with a whorl of bracts just below the terminal flower 9.

  • Flowering stems without such a whorl of bracts 10.

  • Perennials; leaves not finely divided; flowers white or yellow 4. Eranthis

  • Annuals; leaves very finely divided; flowers blue 5. Nigella

  • Perianth segments persisting around the group of follicles 3. Helleborus

  • Perianth segments deciduous in fruit 11.

  • Carpels (and follicles) united, at least towards the base.

  • 2 - Selaginellaceae

  • 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 5-5

  • Summary

    Perennial herbs with long, usually creeping stems producing leafless branches (rhizophores) which bear the roots or arise with them on a corm-like swelling at the base of the stem. Leaves small, spirally arranged or 4-ranked and of two kinds, bearing a minute ligule at the base. Heterosporous. Sporangia in leaf axils, the sporangium-bearing leaves in ill- to well-defined cones, with megasporangia at base and microsporangia at apex. Megaspores (1–)4(–42). Microspores numerous. Male gametophyte contained in the microspore until maturity, with a vegetative cell and an antheridium containing numerous biciliate spermatozoids. Female gametophyte many-celled, filling the megaspore and protruding from its split top; archegonia several, at the top of the prothallus. Fertilisation occasionally takes place before the shedding of the megaspore.

  • 26A - CEPHALO

  • 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 115-116

  • Summary

    Dioecious, evergreen, slow-growing, slightly resinous shrubs or trees. Leaves more or less decussate and more or less opposite, widely spreading around leading shoots, but strongly oriented into two more or less flattened or V-shaped, spreading, pectinate ranks on all side branches and branchlets; lamina uniformly green on upper surface, with 2 broad, paler green, longitudinal bands of stomata beneath, usually set into the leaf, linear, markedly dorsiventrally flattened with a revolute margin and a single conspicuous vein containing a single large ventral resin canal, decurrent at base. Male strobili clustered in globose groups in axils of leaves of the previous year's vegetative shoots or aggregated into a compound terminal inflorescence; pollen globose without air-bladders. Female strobili often few, terminating a reduced vegetative axis, clustered in the axils of the bracts beside the tips of previous year's twigs. Cones large, fleshy and drupe-like, pendulous and stalked; seeds large, unwinged, enclosed within a thin, woody layer.

    Two genera and about 12 species, ranging from the Himalayas to Japan, Taiwan and Thailand.

    Cephalotaxus Siebold & Zucc.

    Small dioecious, evergreen trees and shrubs with yew-like foliage. Leaves persisting for several years, arranged pectinately either side of the shoot, on which they are decurrent. Male strobili are globular heads on previous year's shoots. Female strobili occur at the base of the previous year's shoots. Cones are large and drupe-like, with a fleshy shell on the outside of the long seed, derived from cones in which only one of the ovules matures.

    Contains 9 species restricted to eastern Asia.

  • 50 - Portulacaceae

  • 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 430-434

  • Summary

    Annual to perennial herbs, sometimes subshrubs, usually glabrous, often fleshy. Leaves alternate or opposite and decussate and then sometimes connate, simple and entire; stipules scarious, bristle-like or absent. Flowers bisexual, actinomorphic, hypogynous or half-epigynous. Sepals usually 2, free or united below. Petals 2–6(–18), free or united below, sometimes minute or absent. Stamens (1–)3–20 or rarely more, opposite the petals when equalling them in number. Style simple or with two or more branches. Ovary superior or semi-inferior, usually 1-celled, with one to many ovules on a basal placenta. Fruit a capsule, opening by valves or transversely; seeds one to many, with a curved embryo surrounding the mealy perisperm.

    Contains some 20 genera with about 500 species mainly in temperate and subtropical regions.

  • Cauline leaves spirally arranged; petals purple or reddishpurple 2. Calandrinia

  • At least the upper cauline leaves opposite or subopposite; petals white, yellowish or pink 2.

  • Stamens 6–15; ovary semi-inferior; capsules opening by a lid 1. Portulaca

  • Stamens 3 or 5; ovary superior; capsules opening by 3 valves 3.

  • Plant with a basal rosette and one pair of cauline leaves; stamens 5 3. Claytonia

  • Plant without a basal rosette but with several pairs of cauline leaves; stamens 3 4. Montia

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