Pemphis LYTHRACEAE 135 
heterostylous. Capsule globose, 3-5 mm diam., 
circumscissile. Flowering and fruiting: all year. 
Fig. 41 
Widespread along the coast of northern Australia 
and common in the coastal DR. Found on sand or 
rocky areas. A variety of Aboriginal uses have been 
recorded; highly favoured as timber for digging sticks 
(Wightman, 1989). 
ROTALA L. 
Annual or perennial, glabrous, terrestrial or aquatic herbs. Leaves decussate or whorled, sessile or shortly 
petiolate; stipules absent. Flowers solitary or rarely in reduced cymes, usually regular, 3-5-merous. Hypanthium 
usually campanulate, hyaline. Sepals 3-5; appendages 3-5 or absent. Petals 3-5 or absent. Stamens 2-5, never 
more than sepals. Ovary 2-4-locular. Capsule thin walled, ellipsoid, c. equal to length of flower, dehiscing 
septicidally by valves. 
A genus of c. 45 species; 6 recorded in Australia, 5 in the NT, 4 in the DR. 
1.  Bracteoles leaf-like, usually 2-3 times length of flower 
R. occultiflora 
1. __ Bracteoles filiform to linear, rarely exceeding hypanthium ...............sseessesseseseeseeeeseeneneenes 2 
2. Leaves with conspicuous hyaline margin; capsule valves 2 .......c.ssssssssssesssessseeeseeceesesesees 
2. Leaves lacking hyaline margin; capsule valves >2..... 
3. Leaves decussate or in whorls; petals and hypanthium appendages absent ..............:.:0008 
3. Leaves decussate; petals and hypanthium appendages present 
R. diandra (F.Muell.) Koehne 
Annual erect herb. Leaves decussate, sessile; blades 
ovate to elliptic-oblong, 4-12 mm long, 2.5-9.5 mm 
wide, L/W 1.6-3, base obtuse to cordate, margins 
hyaline. Bracteoles filamentous, 1-2.5 mm long. 
Hypanthium c. 1.5 mm long. Sepals 4, c. 1.5 mm long; 
appendages absent. Perals absent or rarely vestigial. 
Stamens 2. Capsule valves 2. Flowering and fruit- 
ing: Apr - Aug. Fig. 41 
Widespread from the Gulf of Carpentaria to WA. 
Rare in the DR where known from one collection on 
the Mary R. On silty clay soils associated with 
seasonally wet areas. 
R. mexicana Cham. & Schldl. 
Annual, terrestrial or aquatic herbs. Leaves 
decussate or in whorls of 3-8, sessile; blades of aerial 
leaves narrowly elliptic to narrowly lanceolate, 3.5-9 
mm long, 0.9-1.5 mm wide; aquatic leaves linear to 
filiform, to 15 mm long, c. 1 mm wide. Bracteoles 
filiform, about as long as flower. Hypanthium c. 0.5 
mm long. Sepals 3-5, c. 0.25 mm long; appendages 
absent. Petals absent. Stamens 2-4. Capsule valves 
3(4). Flowering and fruiting: Feb - Aug. Fig. 41 
Widespread throughout the warmer parts of the 
world including northern Australia. Scattered in the 
DR; on sandy soils in seasonally moist habitats. 
R. diandra 
eaeesertrerrerrresesnrresertenterererstsrertettttes 3 
R. mexicana 
R. rosea 
R. occultiflora Koehne 
Annual erect herb. Leaves whorled or decussate, 
sessile; blades ovate to linear, elliptic, 3.5-12 mm 
long, 0.8-3.5 mm wide, L/W 2-4.3. Bracteoles leaf- 
like, narrowly elliptic, longer than flower. Hypanthium 
c. 0.5 mm long. Sepals 5, c. 0.5 mm long; append- 
ages absent. Petals absent. Stamens 3(4). Capsule 
valves 3. Flowering and fruiting: Apr - Sept. Fig. 41. 
India and northern Australia. Rare in the DR where 
known only from the Adelaide R. On sandy soils in 
seasonally wet areas. 
R. rosea (Poiret) Cook 
Annual erect herb. Leaves decussate, sessile; blades 
linear-lanceolate to elliptic, to 20 mm long. Flowers 
solitary or in reduced cymes. Bracteoles linear- 
lanceolate or filamentous, usually as long as 
hypanthium. Hypanthium c. 1.5 mm long. Sepals (4)5, 
c. 0.25 mm long; appendages (4)5 or rarely absent, 
subulate. Petals (4)5, elliptic to oblong, usually as 
long as sepals. Stamens 5, rarely less. Capsule valves 
3-4. Flowering and fruiting: May - June. Fig. 41 
Occurs throughout India, SE Asia, New Guinea, 
China, Korea and Japan. In Australia from northern 
NT. No material seen from the DR but one collection 
from Howard Springs cited by Hewson & Beesley 
(1990). 
