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Pakistan | Family List | Euphorbiaceae

24. Euphorbia L., Sp. Pl. 450. 1753. Gen. Pl. ed. 5: 208. 1754; Boissier in DC., Prodr. 15(2): 7. 1862; Benth. & Hook. f., Gen. P1. 3(1): 258. 1880; Hook. f., Fl. Brit. Ind. 5: 244. 1887; Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 447. 1972.

A. RADCLIFFE-SMITH

Euphorbia royleana
Illustration

Credit: M. Rafiq

  • Agaloma Raf.
  • Anisophyllum Haw.
  • Chamaesyce [Diosc.] S.F. Gray
  • Euphorbium Hill
  • Poinsettia Grah.
  • Tithymalus [Tourn.] Trew

    Monoecious herbs, shrubs or trees, often succulent, with milky latex and with a simple indumentum, when present. Leaves often of 3 types, lower, median and upper; lower or stem-leaves usually alternate, median or pseudumbel-leaves whorled, upper or ray-leaves whorled or opposite, free or connate; all or most leaves usually sessile, rarely shortly petiolate, stipulate or not, simple, entire or toothed, penni- or palminerved. Stipules, when present, minute and subulate, interpetiolar and chaffy, glandular and sessile, or spiny. Inflorescence a cyathium, with 1 ♀ flower and several bracteate ♂ flowers enclosed in a gland. bearing involucre; cyathia axillary or arranged pseudodichasially, often in a ‘pseudumbel’' of radiating ‘dichasia’. Involucre usually 5-lobed, with 1-5 glands alternating with them. Male flowers each consisting of a single stamen borne directly on its own pedicel; anther-cells subglobose, longitudinally dehiscent. Female flower consisting of a trilocular ovary on a pedicel which usually elongates in fruit; ovules 1 per cell; styles 3, free or connate at the base, stigmas often bifid. Fruits 3-celled, dehiscent into bivalved cocci; endocarp woody or cartilaginous. Seeds often carunculate; testa thin, crustaceous, smooth, ornamented or sculptured; albumen thick; embryo straight; cotyledons broad, flat.

    One of the six largest genera of flowering plants (the others being Astragalus, Carex, Piper, Senecio and Solanum), having some 2000 species. It is ± cosmopolitan, but chiefly restricted to tropical, subtropical and warm temperate regions.


    1 Plants succulent   (2)
    + Plants woody or herbaceous   (7)
           
    2 (1) Stems unarmed   21 Euphorbia tirucalli
    + Stems spiny   (3)
           
    3 (2) Spines arising from separate tubercles; cyathophylls prominent, red or yellow   16 Euphorbia milii
    + Spines paired on each spine-shield; cyathophylls not prominent, usually scarious   (4)
           
    4 (3) A densely-branched shrub, not forming a trunk   18 Euphorbia caducifolia
    + Trees, forming trunks   (5)
           
    5 (4) Stems Wrote   17 Euphorbia nivulia
    + Stems angled   (6)
           
    6 (5) Angles not produced into wings   19 Euphorbia neriifolia
    + Angles produced into undulate wings   20 Euphorbia royleana
           
    7 (1) Stipules present, sometimes much-reduced   (8)
    + Stipules absent   (22)
           
    8 (7) Leaves all opposite, asymmetrical at the base; stipules scarious, persistent; glands usually appendiculate   (9)
    + Leaves mostly opposite or else alternate, whorled and opposite, symmetrical at the base; stipules subulate, persistent or fugacious, or sessile and glandular; glands usually exappendiculate   (17)
           
    9 (8) Cyathia aggregated together into clusters   (10)
    + Cyathia axillary, solitary, often borne on pecialized lateral shoots   (12)
           
    10 (9) Leaves rhombic; hairs multicellular, yellow; cyathia in dense, axillary, pedunculate clusters   1 Euphorbia hirta
    + Leaves oblong; hairs mostly unicellular, white; cyathia in loose clusters terminating lateral shoots   (11)
           
    11 (10) Plants puberulous or pubescent   2 Euphorbia indica
    + Plants glabrous   3 Euphorbia hypericifolia
           
    12 (9) Plant completely glabrous, rooting at the nodes; stipules fused to form a triangular scale above and beneath   4 Euphorbia serpens
    + Plant glabrous, puberulous, pubescent or hispid, not rooting at the nodes; stipules all free, or only the pairs beneath fused into a scale   (13)
           
    13 (12) Leaves entire or almost so   5 Euphorbia granulata
    + Leaves minutely denticulate, serrulate, or serrate   (14)
           
    14 (13) Glands with prominent white appendages   7 Euphorbia hispida
    + Gland-appendages minute or absent   (15)
           
    15 (14) Plant completely glabrous; leaf-blades narrowly falcate-oblong   6 Euphorbia clarkeana
    + Plant puberulous or pubescent above, glabrous beneath; leaf-blades obovate-suborbicular or ovate-oblong   (16)
           
    16 (15) Fruits glabrous except on the keels; seeds sharply transversely-ridged   8 Euphorbia prostrata
    + Fruits adpressed-pubescent; seeds shallowly transversely-ridged   9 Euphorbia thymifolia
           
    17 (8) Uppermost leaves of the pseudumbel with conspicuous white margins; stipules fugacious   10 Euphorbia marginata
    + Uppermost leaves of the pseudumbel red, green or yellow; stipules persistent   (18)
           
    18 (17) Cyathia usually with 4-5 pectinate glands; stipules subulate, eglandular   (19)
    + Cyathia with only 1 cupular, circular or saccate gland, or rarely glands 2-3; stipules sessile, glandular   (20)
           
    19 (18) Leaves linear to ovate; stipules 1 mm long   11 Euphorbia cheirolepis
    + Leaves all ovate or elliptic-ovate; stipules 0.25 mm long   12 Euphorbia petiolata
           
    20 (18) Leaves elliptic-obovate, elliptic-lanceolate or lanceolate   13 Euphorbia heterophylla
    + At least the lower leaves panduriform   (21)
           
    21 (20) Upper leaves green with a basal red blotch   14 Euphorbia cyathophora
    + Upper leaves uniformly bright scarlet   15 Euphorbia pulcherrima
           
    22 (7) Leaves opposite or whorled, rarely any alternate; annuals   (23)
    + Leaves alternate, whorled and opposite, or, if any stem-leaves opposite, then decussate; annuals, biennials or perennials   (26)
           
    23 (22) Caruncle stipitate, the stalk 0.3-0.5 mm long   (24)
    + Caruncle sessile or subsessile   (25)
           
    24 (23) Leaves linear, less than 2 mm wide; glands ecornute   22 Euphorbia inderiensis
    + Leaves linear-lanceolate, more than 2 mm wide; glands cornute   23 Euphorbia sororia
           
    25 (23) Leaves ovate to linear-lanceolate; glands ecornute   24 Euphorbia aserbajdzhanica
    + Leaves spathulate to suborbicular; glands cornute   25 Euphorbia densa
           
    26 (22) Pseudumbels usually borne on short lateral beanches   26 Euphorbia osyridea
    + Pseudumbels usually terminal   (27)
           
    27 (26) Leaves commonly coarsely and irregularly sharply denticulate   (28)
    + Leaves entire, subentire or minutely and regularly serrulate or denticulate   (31)
           
    28 (27) Annual herb   29 Euphorbia grossheimii
    + Perennial herbs   (29)
           
    29 (28) Stem-leaves not more than 3 cm long; glands madder, maroon or black   30 Euphorbia tibetica
    + Stem-leaves up to 7 cm long; glands ochreous   (30)
           
    30 (29) Stem-leaves linear to oblong-lanceolate; fruits 6 x 5 mm   27 Euphorbia caeladenia
    + Stem-leaves oblong-lanceolate to orbicular-ovate; fruits 4.5 x 4.5 mm   28 Euphorbia multifurcata
           
    31 (27) Glands rounded on the outer edge   (32)
    + Glands truncate, crescentic or 2-(rarely more-) horned   (38)
           
    32 (31) Fruit warty   (33)
    + Fruit smooth   (35)
           
    33 (32) Plant 10-20 cm tall; pseudumbel 3-5-rayed   33 Euphorbia micractina
    + Plant 40-100 cm tall; pseudumbel 5-15-rayed   (34)
           
    34 (33) Leaves subentire or serrulate; fruits densely covered with conical warts   31 Euphorbia cornigera
    + Leaves entire; fruits sparingly warty   32 Euphorbia cognata
           
    35 (32) Annual herb   37 Euphorbia helioscopia
    + Perennial herbs   (36)
           
    36 (35) Fruit 3-4 mm diam   36 Euphorbia jacquemontii
    + Fruit 5.5-8 mm diam   (37)
           
    37 (36) Stem-leaves elliptic-ovate or elliptic, 1-5 cm long   34 Euphorbia thomsoniana
    + Stem-leaves ovate-lanceolate or elliptic-lanceolate, 4-11 cm long   35 Euphorbia wallichii
           
    38 (31) Annual herbs   (39)
    + Biennial or perennial herbs   (42)
           
    39 (38) All leaves linear to linear-lanceolate   38 Euphorbia dracunculoides
    + Leaves variable, the upper differing from the stem-leaves   (40)
           
    40 (39) Stem-leaves petiolate; fruits 2-ridged on the keels   41 Euphorbia peplus
    + Stem-leaves sessile; fruits with rounded keels   (41)
           
    41 (40) Ray-leaves cuspidate-aristate   39 Euphorbia falcata
    + Ray-leaves obtuse or rounded   40 Euphorbia maddenii
           
    42 (38) Stem-leaves opposite, decussate; fruit spongy   52 Euphorbia lathyris
    + Stem-leaves alternate; fruit hardened   (43)
           
    43 (42) Glands truncate, hornless   51 Euphorbia seguieriana
    + Glands truncate or crescentic, usually 2-horned   (44)
           
    44 (43) Plants decumbent- or procumbent ascending   (45)
    + Plants erect, rarely ascending   (46)
           
    45 (44) Seeds ovoid-hexagonal; NWFP & Kashmir   42 Euphorbia kanaorica
    + Seeds compressed-ovoid; Baluchistan   43 Euphorbia aucheri
           
    46 (44) All leaves linear-lanceolate; seeds tuberculate-rugulose   38 Euphorbia dracunculoides
    + Upper leaves differing from the stem-leaves   (47)
           
    47 (46) Pseudumbel-rays often proliferating as densely-leafy shoots   45 Euphorbia prolifera
    + Pseudumbel-rays not proliferating   (48)
           
    48 (47) Stem-leaves usually obovate or oblanceolate   (49)
    + Stem-leaves usually linear or lanceolate   (50)
           
    49 (48) Pseudumbel-rays rarely more than once or twice bifid; Baluchistan   44 Euphorbia microsciadia
    + Pseudumbel-rays commonly 4-5 times bifid; NWFP, N. Punjab & Kashmir   40 Euphorbia maddenii
           
    50 (48) Plant not exceeding 25 cm in height; ray leaves usually trullate   46 Euphorbia talaina
    + Plant 30-140 cm tall   (51)
           
    51 (50) Stem-leaves lanceolate; ray-leaves ovate-deltoid; glands truncate, 2-horned   47 Euphorbia thyrsoidea
    + Stem-leaves usually linear; ray-leaves transversely elliptic to suborbicular; glands crescentic   (48. - 50. E. virgata agg.) 52
           
    52 Stem-leaves more than 1 cm wide   48 Euphorbia boissieriana
    + Stem-leaves not more than 8 mm wide   (53)
           
    53 (52) Stem-leaves up to 8 mm wide   49 Euphorbia cyrtophylla
    + Stem-leaves not more than 4 mm wide   50 Euphorbia pamirica

  • List of lower taxa


     

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