Trees or shrubs, rarely herbs, dioecious or monoecious, evergreen. Leaves alternate,
lower ones rarely opposite, often pellucid-dotted above in living plants with protruding points
which become scabrous when dry, penninerved, rarely palmately 3-nerved at base, usually long-petioled; stipules small or minute. Flowers small, in axillary or lateral spikes or racemes,
solitary or 2 together. Male flowers: 1 - many fascicled in each bract; calyx subglobose, closed
in bud, splitting into 3 or 4 valvate segments; petals and disc absent; stamens 3 - 60 or more,
free, inserted on or around a central flat, vaulted, convex or elevated receptacle, often intermixed
with intrastaminal glands or long linear scales or hairs; filaments free, short; anthers erect;
thecae distinct, connate at base, free above, extrorsely dehiscing; pistillode absent. Female
flowers: solitary in each bract; sepals 3 (- 5), shortly connate at base; disc absent or consisting
of petal-like hypogynous scales, glandular, enlarged, 2 - 3-lobed with elongate liguliform lobes
alternating with the carpels; staminodes absent; ovary (2 -) 3 (- 4)-loculed; ovule solitary in each
locule; styles same number as ovary-locules, coarsely papillose inside, often plumose; stigmas
short, divided into fringed segments or rarely smooth. Fruits schizocarpic capsules, 2 or 3 (- 4)-
locular, deeply or shallowly lobed, fleshy or coriaceous, dehiscing loculicidally and septicidally
or indehiscent; seeds subglobose, with a fleshy outer and hard foveolate-reticulate crustaceous
inner layer (testa), thinly arillate or not arillate; endosperm fleshy; cotyledons broad, flat.
Paleotropical, spread over Africa, Asia, Australia, extending eastwards to Pacific Islands,
up to Society Islands, ca 113 species; 9 species in India.
Literature.
PRAIN, D. (1911). A review of the genera Erythrococca and Micrococca. Ann. Bot.
(Usteri) 25: 575 – 638. SAGUN, V. G. & P. VAN WELZEN (2002). Revision of the Malesian species of
Micrococca (Euphorbiaceae). Blumea 47: 149 – 155. SUSILA RANI, S. R. M. & N. P. BALAKRISHNAN
(1992). Claoxylon wightii Hook. f. (Euphorbiaceae) and its allies. J. Econ. Taxon. Bot. 16: 733 – 736.
SUSILA RANI, S. R. M. & N. P. BALAKRISHNAN (1995). A revision of the genus Claoxylon Adr.
Jussieu (Euphorbiaceae) in India. Rheedea 5: 113 - 141, ff. 1 - 8.
Notes.
Following Prain (1911), Sagun & van Welzen (2002) treat Micrococca and Claoxylon
as independent genera. However, they have not seen the paper by Susila Rani & Balakrishnan
(l. c. 1995), nor have they studied Indian species of Claoxylon. Micrococca Benth. is based on
certain differentiating characters, i. e. the herbaceous nature, the opposite lower leaves,
interrupted racemes, lesser number (3 - 20) of stamens, plumose styles, loculicidally and
septicidally dehiscing capsules with thinly arillate seeds. However, analysis of all Indian species
of Claoxylon indicated that these characters are variable and often becomes intermediate.
There are two species endemic to India, C. beddomei and C. wightii, which show a bridge
between Micrococca and Claoxylon. The herbaceous nature of M. mercurialis continues into
Claoxylon where the species are subshrubs, shrubs or trees. The lower leaves are sometimes
opposite in C. anomalum and they are subopposite in C. wightii. The interrupted racemes
occur in both genera but only in varying degrees. The stamen number varies from 3 to 10 in
Micrococca and from 20 to 60 or more in Claoxylon. M. mercurialis itself shows regional
variation with 3 stamens in Asia and 9 stamens in Africa. C. beddomei and C. wightii show 5 -
20 stamens. The disc lobes are present in female flowers of both genera; only the length versus
breadth varies showing different lengths in Indian species, sometimes becoming minute and
indistinct. In C. anomalum, the female disc is annular with three lobes and each lobe triangular
and appressed to the ovary. In C. indicum, C. beddomei and C. wightii, the female disc
consists of 3 oblong-ligulate lobes each 1 – 2 mm long. The capsules of C. indicum dehisce
both loculicidally and septicidally. In other species, there are no records to show whether both
types of dehiscence occur or not, a feature that only careful field observation will show. At the
same time, there are certain dependable and invariable characters common to both these genera,
i. e. the constantly 3-sepaled male flowers, the divaricate anther-thecae which are connate at base and free above, the stamens mixed with ciliate scales or glands, the presence of pits over
seeds, etc., which indicate commonality and propinquity of these genera. Therefore, keeping
them separately is not justified by facts. It is also not practical to differentiate them by any
decisive character. Therefore, they are combined and treated here as a single genus, as was
done by Mueller Argoviensis (1866) and J. D. Hooker (1887).
KEY TO THE SPECIES
1 a. Stamens (3 -) 5 - 12 (- 20)
2
b. Stamens 20 - 60 or more
4
2 a. Male receptacle without interstaminal glands, with extra-staminal glands outside the stamens
b. Male receptacle convex or flat, not elevated, glandular and often with scales or hairs intermingled
with stamens, without a ring of pilose hairs below the stamens
5
5 a. Capsules flattened, inflated at middle, 2-locular, 2-lobed, cuneate at base, conspicuously beaked at apex
