Trees or shrubs, rarely herbs, monoecious or rarely dioecious, densely or sparsely clothed
with stellate hairs or lepidote scales, occasionally glabrous; stems with coloured or rarely milky
sap. Leaves simple, alternate, petiolate, penninerved or palmatinerved at base, with 2 (- 10)
sessile or stipitate glands at junction of petiole and lamina; stipules caducous. Inflorescences
terminal and sometimes axillary, racemiform cymes or thyrses, androgynous or occasionally
unisexual; female flowers solitary at lower nodes; male flowers in fascicles at upper nodes;
bracts shortly subulate or triangular. Male flowers: sepals (4 -) 5 (- 6), valvate; petals isomerous
with free sepals; disc glands small, opposite to sepals; stamens 8 - 40, free, arranged in whorls;
filaments mostly lanate towards base, inflexed at apex in bud; anthers basifixed, 2-loculed, the
thecae usually parallel or slightly diverging, adnate to a broad connective, longitudinally
dehiscent; pistillode absent; receptacle densely lanate or rarely glabrous. Female flowers:
sepals (4 -) 5 (- 10), shortly connate at base, valvate or sub imbricate; petals 0 - 5 (-6), smaller
than the sepals or vestigial; disc glands small; staminodes absent; ovary (2 -) 3 (- 5)-locular;
styles 3, free or shortly connate below into a column, once or repeatedly bifid above into linear
or thickened branches; ovule one per locule. Fruits capsular, smooth or often muriculate,
usually 3-seeded; columella persistent; seeds usually 3-angled with a broad convex back,
carunculate; testa dry, thin; endosperm copious; embryo straight; cotyledons broad.
Tropics and subtropics of Old and New World, the majority of the species being in South
America and West Indies, ca 1200 species in the world. In Asia, ca 150 species occur in S. China,
Indo-China, S. & SE. Asia and Malesia. In India 16 species are found.
Literature.
CHAKRABARTY, T. & N. P. BALAKRISHNAN (1997). A revision of Croton L.
(Euphorbiaceae) for Indian subcontinent. Bull. Bot. Surv. India 34: 1 - 88.
Notes.
Species of Croton contain a great diversity of chemical compounds, viz. several
kinds of alkaloids, saponins, tannins and flavanoids. Some species exhibit antimicrobial,
antimalarial, antiatherogenic, androgenic, insecticidal and antitumour activities. There is great
scope for further studies on the Phytochemistry of this genus.
KEY TO THE SPECIES
1 a. Introduced weedy herbs
2
b. Indigenous trees, shrubs (rarely scandent) or undershrubs
3
2 a. Plants sparsely whitish stellate-pubescent to glabrescent; trichomes soft, without erect central
ray; leaves penninerved; glands at the base of lamina sessile; female sepals more or less e
b. Plants more or less densely ochraceous stellate-hirsute to scabrid; trichomes harsh with pronounced central ray; leaves strongly trinerved at base; glands at the base of lamina shortly stipitate; female sepals distinctly unequal
b. Leaves penninerved, distantly scattered lepidote or glabrous above, membrous to thin-coriaceous
5
5 a. Foliar glands stipitate; young leaves with fine detersible stellate hairs on upper surface; trichome-
base mostly colourless; style-branches twice or thrice bifid; leaves often subopposite or
pseudo-verticillate and separated by long internodes
b. Foliar glands sessile; young leaves with detersible lepidote scales on upper surface; trichomebase
mostly coloured; style-branches once bifid; leaves never separated by long internodes
6
6 a. Fruits obovoid, large, 18 - 25 mm long, ca 15 mm across, shortly stipitate
7 a. Indumentum of young shoots, petioles, rachis and flowers lepidote
8
b. Indumentum of young shoots, petioles, rachis and flowers stellate-pubescent or lacking
9
8 a. Leaves very coarsely dentate-serrate-crenate; webbing of scales at least 80%, free portion of
rays radiating in one plane; ovary intruded at apex; fruits much smaller, subglobose, up to 1 cm
long, 0.8 - 1.2 cm across, prominently lobed
b. Leaves shallowly or evenly serrate-dentate to subentire; webbing of scales 50% or less, free
portion of rays radiating in all directions; ovary obtuse or rounded at apex; fruits ovoid-
ellipsoid or oblong or obovoid, larger, 2.5 - 3.5 cm long, 2 - 2.5 cm across, obscurely lobed
b. Petioles distinctly deeply channelled above; rachis glabrous or almost so (Peninsular India)
12
12a. Fruits larger (10 - 14 mm in diam.); leaves usually larger (7 - 25 cm long); basal glands of leaves
shortly stipitate; inflorescences usually elongate, 12 - 30 cm long
b. Fruits smaller (6 - 10 mm in diam.); leaves usually smaller (2 - 10 cm long); basal glands of
leaves subsessile; inflorescences mostly shorter, 3 - 10 cm long
