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Malesian Euphorbiaceae Descriptions |
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Welzen, P.C. van. 1999. Revision and Phylogeny of subtribes Chrozophorinae and Doryxylinae (Euphorbiaceae). Blumea 44: 411--436.
Phylogeny of Chrozophorinae s.l.
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Chrozophora Neck. ex A.Juss., Euphorb. Gen. (1824) 27 (‘Crozophora’),
nom. &
orth. cons.; Müll.Arg. in DC., Prodr.
15, 2 (1866) 746; Pax & K.Hoffm. in Engl., Pflanzenr.
IV.147.vi (1912) 17; Prain, Bull. Misc. Inform.
(1918) 49; Airy Shaw, Kew Bull. 26 (1972) 232; G.L.Webster, Ann. Missouri Bot.
Gard. 81 (1994) 73; Welzen, Blumea 44 (1999) 419; Radcl.-Sm., Gen. Euph. (2001)
151. --- Type species: Croton
tinctorium L. [= Chrozophora tinctoria
(L.) A. Juss.]
Herb or undershrub, monoecious. Indumentum
consisting of very dense, sessile and peduncled stellate or lepidote hairs, next
to simple hairs (latter mainly on lower leaf surface). Stipules
narrowly triangular, tomentose, caducous, scars very indistinct. Leaves
spirally arranged, simple; petiole not pulvinate, reniform in transverse
section; blade ovate, often 3-lobed, coriaceous, symmetric, margin shallowly to
laxly but distinctly crenate, apex rounded, upper surface less densely covered
by hairs than lower surface, the latter usually basally with 2 glands near
insertion and often with submarginal glands, glands crater-like (circular,
rim-like wall, concave inside); venation basally trinerved, pinnate along midrib
with nerves ending open in the margin, veins laxly scalariform, quaternary veins
reticulate. Inflorescences terminal
racemes (in fruit pseudo-lateral and opposite to leaf due to extension of
axillary buds), solitary (or 2 together), not branching, basal flowers
pistillate, apical ones staminate; rachis tomentose. Bracts
narrowly triangular, only hairy outside. Flowers
actinomorphic, staminate flowers usually 2 per node, pistillate flowers usually
single; pedicels with abscission zone; calyx 5-lobed, valvate, tomentose
outside, glabrous inside; petals 5; disc indistinct, glabrous. Staminate
flowers subsessile; calyx campanulate, lobes ovate; petals slightly larger
than sepals, obovate, petaloid, margin in upper part undulate, with simple hairs
on both sides; disc divided into small glands, united with petals; stamens
13--16, glabrous, filaments united into a column, branching off in c. 3 layers,
free part thread-like, anthers basidorsi-fixed, 4-locular, opening extrorse with
lengthwise slits; pistillode absent. Pistillate
flowers pedicellate; calyx and petals persistent, both 5-merous, narrowly
ovate, hairy outside, glabrous inside, petals sepaloid in texture, slightly
smaller than calyx; disc annular, very flat; pistil 3-locular, on short
gynophore, one ovule per locule, smooth, covered by flat stellate hairs; style
short, hairy, persistent; stigmas almost completely divided, below stellately
hairy, above with long slender papillae, persistent. Fruits slightly lobed capsules, triangular in transverse section,
dehiscing usually septicidally and partly loculicidally into 3 bivalved parts,
outside densely stellate, inside glabrous, thin-walled; column slender, with
frayed remnants of the septa, apically triangular; septa single veined?. Seeds
3 per fruit, obovate, angular; covered by a thin, incomplete sarcotesta; the
latter carunculate apically. Embryo
flat; endosperm copious.
Distribution --- Eleven species from Africa
and the Mediterranean through SW and S Asia to SW Asia. In Malesia a single
species, probably accidentally introduced into Central Java.
Chrozophora
rottleri (Geiseler) A.Juss. ex Spreng., Syst. Veg. 3 (1826) 850; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi (1912) 19; Prain, Bull. Misc. Inform.
(1918) 95 (see there for full synonymy); Steenis, Bull.
Jard.
Bot. Buitenzorg ser. 3, 17 (1948) 399; Nath, Bot.
Surv.
S. Shan States (1960) 109; Backer & Bakh.f., Fl.
Java 1 (1964) 477; Welzen, Blumea 44 (1999) 420, Fig. 2, Map1. ---
Croton
rottleri Geiseler, Croton Monogr. (1807) 54; A. Juss., Euphorb. Tent. (1824)
28 --- Chrozophora plicata (Vahl) A.Juss. ex Spreng. var.
rottleri
(Geiseler) Müll.Arg. in DC., Prodr. 15, 2 (1866) 747. --- Type: Vahl
s.n., s.d. (C, n.v.; IDC microfiche 2201-1).
Herb to undershrub, up to 60 cm high;
flowering twigs 2--2.5 mm thick. Indumentum
consisting of stellate and (few) simple hairs. Stipules 1.3-2.7 by c. 0.3 mm. Leaves:
petiole 0.8--5.5 cm long; blade ovate, not to usually distinctly 3-lobed, 2.6--9
by 2.6--9 cm, index 1--1.9, pale green, base obtuse to usually emarginate,
margin without distinct glands, lower surface with 2 glands near the base, 1 mm
in diam., and usually several smaller ones submarginally, venation impressed
above, raised below, nerves c. 4 per side. Inflorescences
up to 4 cm long, elongating in fruit to up to 10 cm long. Bracts
very inconspicuous to c. 1.6 by 0.3 mm. Staminate
flowers 4--6 mm in diam., yellow; calyx white, united part c. 1 mm high,
lobes 3.2--4 by c. 1.2 mm; petals 3.7--3.8 by 1.5--1.6 mm; androphore 3.3--3.8
mm long, basal 1.2--1.3 mm without filaments; filaments 0.3--0.8 mm long;
anthers 0.9--1.3 by c. 0.7 mm, yellow. Pistillate
flowers 3.2--3.3 mm in diam., (greenish to) yellow; pedicel 1.4--2 mm long,
elongating in fruit to up to 1.1 cm; calyx lobes only basally united, 1.5--2.2
by 0.5--0.7 mm; petals 1.3--2 by 0.4--0.6 mm; ovary ovoid, 2.7--3 by 2.2--3 mm
wide; style 0.5--0.8 mm long, red, stigmas erect, up to 2.3 mm long, apically
split for up to 1.8 mm, red. Fruits
8--9 by c. 5 mm; column after dehiscence 3--3.5 mm long. Seeds 3.8--3.9 by 3.2--3.6 by 3--3.2 mm.
Distribution --- India, Myanmar, Thailand, Andaman Islands, and Malesia: Central Java. The plant has probably been introduced accidentally into Java, because it is only known from an area of a sugar cane factory.
Habitat & Ecology
--- Locally common in
wet places like waste areas, along roads, and along and in stream beds. Soil:
clay (mud), sand. Alt.: 10--200 m. Flowering and fruiting: Dec.-Sep., but
perhaps the whole year through.
Uses --- The fruits provide a blue-colouring
dye, though the plant has never been cultivated for this purpose.
Note --- C. plicata (Vahl) A.Juss. ex Spreng. is often confused with C. rottleri, because one of the first leads in Prain’s key (1918) asks for the length of the inflorescence relative to the surrounding leaves. The inflorescence should be shorter than the leaves in C. plicata and longer in C. rottleri. However, they are only longer in C. rottleri when the inflorescences are old and have shed their seeds. The best character to separate both species is in the stellate hairs on the ovary/fruit, these hairs are flat, 2-dimensional, almost lepidote in C. rottleri (lacking the patent hairs), and normal, 3-dimensional in C. plicata. Furthermore, the leaf blades in C. plicata are usually smaller (less than 3 cm long) and of a much darker green (at least when dry).
