Gonocarpus 
G. chinensis (Lour.) Orchard subsp. chinensis 
A low spreading perennial herb up to 30 cm tall; 
stems decumbent. All vegetative parts with sparse 
adpressed hairs. Leaves sessile or with petioles to 1 
mm long; blades linear to narrowly lanceolate, 8-22 
mm long, 1-6 mm wide, base truncate to cordate. 
Inflorescences spicate, borne terminally and in the 
axils of the upper leaves; bracts narrow triangular to 
lanceolate, c. 1.5 mm long. Pedicels c. 0.2 mm long; 
bracteoles linear, 0.5-0.8 mm long. Sepals brown, 
narrow triangular, c. 0.8 mm long, glabrous, with a 
small median basal callus. Petals pink, 1.5-2 mm long. 
Anthers yellow. Fruit shortly pedicellate, silvery grey, 
sub-globular, c. 1 mm long, 8-ribbed, with 1-2 
irregular calli arising obliquely from the ribs. 
Flowering and fruiting: Apr - Sept. Fig. 38 
In Australia, found in the northern NT and 
Kimberley, also extending through Malesia and 
southern China. Rare in the DR, where known only 
from one collection made near the Adelaide R. last 
century. Locally, this species grows in sandy soils in 
damp situations. Another taxon, G. chinensis subsp. 
verrucosus (Maiden & E.Betche) Orch. occurs along 
the east coast, and as an introduced weed in Hawaii. 
Gonocarpus 
G. chinensis subsp. chinensis 
HALORAGACEAE 129 
G. leptothecus (F.Muell.) Orchard 
An annual or perennial subshrub to 1 m tall, with 
erect stems. All vegetative parts scabrous with 
erect hairs. Petioles 0-4 mm long. Leaf blades 
concolorous, lanceolate, elliptic to narrow-elliptic 
or spathulate, 11-47 mm long, 4-19 mm wide. 
Inflorescences of terminal leafy panicles; bracts 
lanceolate to narrowly ovate, 2.5-4 mm long, 
0.5-1 mm wide. Pedicels c. 1 mm long; bracteoles 
at base of pedicel, stramineous, c. 1 mm long, with 
glandular hairs borne on the irregular marginal 
teeth. Sepals green, broadly triangular, c. 0.8 mm long, 
glabrous. Petals pink to green, linear, c. 2.5 mm long. 
Anthers pink. Fruit pale brown, cylindrical, 1.5-2 mm 
long with 4, 3-5-angled tubercules between pairs 
of ribs. Flowering and fruiting: Feb - July (Nov). 
Fig. 38 
Widespread and common north of 17°S 
latitude, from the Qld Gulf Region to the Kimberley. 
Uncommon in the DR where it is known from Melville 
Is., Pine Creek and the Litchfield area. Found 
growing in sandy-surfaced soils in a variety of 
habitats from swamps to rocky slopes and sandstone 
plateaus. 
G. leptothecus 
Fig. 38 
MYRIOPHYLLUM L. 
Annual or perennial emergent aquatic herbs affixed to sediments by roots from the lower nodes. Stems 
often reddish in emergent parts. All parts glabrous. Leaves dimorphic; submerged leaves pectinately divided, 
emergent leaves entire or serrate. Inflorescences simple. Flowers unisexual or bisexual, solitary in the axils of 
emergent leaves, sessile, sometimes one or both whorls absent. Petals pink. Ovary of 4 carpels; stigmas 
capitate, fimbriate. Fruit variously ornamented, splitting at maturity into 4, 1-seeded mericarps. 
An almost cosmopolitan genus of c. 60 species, with a major centre of diversity in Australia. Six species are 
known from the NT, with 2 occurring in the DR. Often commonly known as Water Milfoil. 
