Jacksonia FABACEAE 91 
JACKSONIA R.Br. ex Sm. 
A genus of c. 37 species endemic in Australia, with most species in south west WA. Seven named species in 
the NT; 1 from the DR. 
J. dilatata Benth. 
An erect, grey-green perennial shrub to 4 m tall, 
outer branchlets angular. Stipules absent. Leaves 
reduced to persistent brown bracts c. 1.5 mm long, 
the ultimate flowering branchlets expanded to 
resemble flat leaves (cladodes). Cladodes elliptic to 
narrowly elliptic, 26-150 mm long, 4-20 mm wide, 
densely and shortly sericeous with hyaline hairs. 
Inflorescence borne on the ends of the cladodes, 
spicate, crowded, 6-45 mm long; bracts ovate-elliptic, 
3-6 mm long, acuminate. Calyx 7-8 mm long, 
sericeous; tube c. 2 mm long; lobes 5, equal; c. 2 mm 
wide. Corolla yellow, glabrous + equal to calyx; 
standard orbicular to reniform, 6-7 mm long, 8-9 mm 
wide; wings oblong, 5-7 mm long, c. 2 mm wide; 
keel 5-6 mm long, 2.5 mm wide. Stamens 10, arising 
from a short sheath of tissue adnate to the calyx tube; 
filaments free, of varying lengths; anthers uniform, 
dorsifixed, versatile. Ovary sericeous; ovules 2. Pod 
brown, elliptic, flattened, c. 5 mm long, 3.5 mm wide, 
sericeous with brown hairs. Seed 1, longitudinal in 
pod, mottled, olivaceous, reniform, c. 2.7 mm long, 
1.5 mm wide; hilum central; ecarunculate. Flowering 
and fruiting: May - Nov. Fig. 27 
Commonly forming thickets on sandy soils, on 
skeletal soils on sandstone, on beach dunes, and on 
lateritic soil in less fire prone habitats. Used by 
Aboriginal people in the Top End to treat diarrhoea 
(Abor. Comm. NT, 1988) or as an antiseptic 
(Levitt, 1981). 
LEPTOSEMA Benth. 
An Australian endemic genus of c. 6 species (NT, WA, SA); 4 in the NT, 1 in the DR. 
L. sp. [Brachysema uniflorum Benth.] 
Prostrate, rarely erect, perennial shrub. Stems 
expanded into cladodes, 2-4 mm wide, glabrous or 
glabrate, the hairs simple, hyaline. Stipules absent. 
Leaves scale-like. Flowers solitary; pedicels, calyx 
and pod thinly sericeous. Pedicels 8-14 mm long, 
dilated at apex; bracteoles minute, caducous, in 
middle of pedicel. Calyx coriaceous, 6-8 mm long, 
lobed almost to the base; lobes 5, + equal. Corolla 
dark red, glabrous; standard sessile, deeply constricted 
about the middle, narrow-navicular, shorter than the 
other petals; wing and keel petals shortly clawed; 
wings obscurely lamellate; keel petals pouched, joined 
at apex. Stamens 10; filaments free; anthers dorsifixed 
near base. Ovary + sessile, sericeous, c. 16-ovuled; 
style stout, shorter than the ovary, glabrous in the 
upper part; stigma minute. Pod grey, + woody, 
inflated, dehiscent, ellipsoid, 17-28 mm long, 5-9 mm 
wide. Seeds pale brown to black, reniform, c. 4 mm 
long, 2.2 mm wide, smooth or with scalariform 
patterning, ecarunculate. Flowering and fruiting: Apr 
- July. Fig. 27 
An NT endemic; in the DR known from Melville 
Is., otherwise restricted to-Arnhem Land. Currently 
known as Brachysema uniflorum; transfer of this 
species to Leptosema is proposed. 
MACROPTILIUM (Benth.) Urban 
Annual or perennial vines or herbs. Hairs where present appressed, simple with slightly swollen bases, the 
pods also with short conical tuberculate glandular hairs. Stipules persistent, striate. Leaves digitately 3-foliolate; 
stipels persistent. Inflorescence axillary, racemose; flowers paired, arising from swollen glandular nodes. 
Bracts and bracteoles caducous, striate. Calyx lobes 5, + equal, to c. 1/3 of total length. Corolla glabrous 
except for inner margin of keel petals; standard pink or pinkish, reflexed, broadly clawed, with obscure 
auricles, calli absent, apex emarginate; wings greatly exceeding other petals, long-clawed; keel petals long- 
