38 CAESALPINIACEAE 
*S. occidentalis (L.) Link 
Cassia occidentalis L. 
Erect annual shrub to 1.2 m. Sparse simple hairs 
on leaflet margin, rachis and pedicels, sparse minute 
colleters on undersurface of leaflets, leaf rachis, stems 
and pods. Stipules caducous. Leaves terminated by a 
bristle, 3-5 pairs of leaflets, erect gland just above 
pulvinus, rachis to basal leaflets 30-57 mm long, 
rachis 85-165 mm long; leaflets 3-5 pairs, lanceolate 
to obovate, 35-120 mm long, 15-39 mm wide, L/W 
1.8-3.7. Inflorescence terminal or axillary racemes 
to 130 mm long. Bracts lanceolate, long acuminate, 
6-15 mm long; bracteoles absent; pedicels 4-9 mm 
long. Sepals unequal, elliptic, 7-10 mm long. Petals 
unequal, spathulate to obovate, 8-15 mm long. Func- 
tional stamens 6-7, beaked, 2 enlarged; staminodes 
3-4. Ovary hairy, sessile; stigmatic surface linear, on 
underside of curved style, hairy. Pods pale brown with 
broad pale margins, slightly flattened and curved, 100- 
130 mm long, 8-10 mm wide. Seeds 21-50, transverse 
in pod, olivaceous to grey-brown, obovate to oblong, 
4.2-4.7 mm long, 2-4 mm wide, broad areole c. 1.1 
mm wide. Flowering and fruiting: Jan - July. Fig. 14 
Probably a native to the American tropics. Now 
widespread in the tropics and throughout northern 
Australia. A common weed in the DR in disturbed 
habitats. 
S. procumbens Randell 
Prostrate or procumbent shrub, annual aerial parts 
from a perennial rootstock. Indumentum of very 
sparse simple white hairs and colleters or glabrous. 
Stipules persistent, linear, 6-9 mm long. Leaves 
terminated by a long bristle, erect terete gland 
between leaflets, rachis to basal leaflets (5)10-66 mm 
long, rachis 24-44 mm long; leaflets 1-3 pairs linear- 
oblong to narrowly elliptic, asymmetric at base, 
35-58 mm long, 7-15 mm wide, L/W 2.5-5.5. 
Inflorescence axillary, umbelliform, 40-65 mm 
long, 5-8-flowered. Bracts persistent, triangular, 
ciliate, 3-4 mm long; bracteoles absent; pedicels 
13-14 mm long. Sepals unequal, elliptic, 4.5-7 mm 
long. Petals obovate, 11-18 mm long. Stamens 10, + 
equal, apiculate. Ovary glabrous. Pods [from Randell, 
1989] 50-70 mm long, 8 mm wide, dark, straight or 
slightly curved, edge not crenate. Seeds not seen. 
Flowering: Jan. Fig. 14 
An NT endemic known only from the Pine Creek 
area in woodland on sandy soils. 
S. surattensis (Burm. f.) Irwin & Barneby 
Cassia surattensis Burm.f. 
Shrub or small glabrate tree to 7 m. Stipules 
subpersistent, linear, to 15 mm long. Leaves termi- 
Senna 
nated by a bristle, 5-8 pairs of leaflets, erect terete 
gland between lower 2-4 pairs of leaflets, rachis to 
basal leaflets 20-60 mm long, rachis 90-170 mm long; 
leaflets 5-8 pairs, elliptic to obovate, 20-50 mm long, 
13-25 mm wide, L/W 1.6-2.3. Inflorescence an 
axillary raceme or subumbelliform, to 100 mm long. 
Bracts narrowly-elliptic, 4.5-6 mm long; bracteoles 
absent; pedicels 14-21 mm long. Sepals unequal, + 
orbicular, ciliate, 7-10 mm long. Petals + equal, 
obovate, 11-19 mm long. Stamens + equal, 10, beaked. 
Ovary hairy; stigma minute. Pods brown, flattened, 
stipitate, oblong, + straight, 90-140 mm long, 10-13 
mm wide, glabrous. Seeds 12-26, transverse in pod, 
black, shiny, oblong to elliptic, 5-6 mm long, 2.7-3.5 
mm wide, areole 0.9-1.2 mm wide. Flowering and 
fruiting: Feb - June. Fig. 14 
Native to SE Asia. Sometimes recorded as 
introduced in Australia but early collections by Robert 
Brown in 1802 indicate the species is native in the 
NT. It is found across northern Australia but is rare in 
the DR where known from Melville Is. and 
Darwin. On dunes and laterite along the coast, 
associated with vine thicket. 
S. timoriensis (DC.) Irwin & Barneby 
Cassia timoriensis DC 
Shrub to 3 m rarely higher. Indumentum of dense, 
patent hairs, rusty on young growth, sometimes 
glabrate on upper leaflet surface. Stipules caducous. 
Leaves without glands, rachis to basal leaflets (6)11- 
30 mm long, rachis 110-210 mm long; leaflets 14-22 
pairs, narrowly elliptic, lanceolate or oblong, 19-42 
mm long, 5.5-15 mm wide, L/W 2.1-4. Inflorescence 
axillary racemes or terminal panicles to 70 mm long. 
Bracts caducous, ovate, c. 2.5 mm long; fruiting 
pedicels 18-25 mm long. Sepals unequal, + orbicular 
to narrowly triangular, 3-5.5 mm long. Petals elliptic, 
9 mm long. Functional stamens 7, variable in size, 
beak absent; staminodes 3. Ovary sparsely hairy at 
base, shortly stipitate; stigma minute. Pods brown, 
stipitate, flattened, oblong, + straight, 8-17-seeded, 
55-94 mm long, 9-12 mm wide. Seeds transverse, 
obovate to oblong, flattened, 5-7 mm long, 3-7 mm 
wide, areole c. 0.7 mm wide. Flowering: Mar; fruiting: 
Mar - Aug. Fig. 14 
Timor and northern Australia. Rare in the DR where 
known only from granite hills at Mt Bundey. Recorded 
on rocky hills of sandstone or granite; usually 
associated with vine thicket. 
*S. tora (L.) Roxb. 
Erect annual to 70 cm. Indumentum of simple 
appressed hairs. Stipules persistent, linear, 5-8 mm 
long. Leaves with 3 pairs of leaflets, pulvinus 
