Austrobaileya 8 ( 1 ): 103-105 ( 2009 ) 
103 
SHORT COMMUNICATION 
Reinstatement of Enydra woollsii F.Muell. 
(Asteraceae: Heliantheae) 
A.R. Bean 
Queensland Herbarium, Department of Environment & Resource Management, Brisbane Botanic 
Gardens, Mt Coot-tha Road, Toowong, Queensland 4066, Australia. Email: tony.bean@derm.qld. 
gov.au 
Enydra Lour, is a small genus of hydrophilous 
forbs that occurs in the tropics and subtropics 
of South America, Africa, Asia and Australia. 
The number of species is often quoted as ten 
(e.g. Stuessy 1977; Stanley & Ross 1986; Hajra 
et al. 1995). The accepted Old World species 
are E. fluctuans Lour., reported for south¬ 
east Asia, Australia and tropical Africa and 
E. radicans (Willd.) Lack, shared by tropical 
Africa and South America. 
Enydra woollsii was described by 
F. Mueller from Australian material in 1863. 
Bentham (1867) placed E. woollsii into 
synonymy with E. paludosa (Reinw. ex 
Blume) A.DC., and E. paludosa was later 
relegated to synonymy with E. fluctuans. 
Descriptions and illustrations of Asian 
Enydra fluctuans (e.g. Soerjani et al. 1987; 
Hajra et al. 1995) strongly indicated to me 
that it was morphologically different to the 
Australian taxon. A comparison of herbarium 
specimens has confirmed this. The ecology of 
the Asian plant also appears different. While 
the Australian taxon is strictly terrestrial, 
E. fluctuans from Asia and Africa has been 
described as a “free-floating plant” (Lack 
1980) or an “aquatic” (Hajra et al. 1995), and 
Nguyen (1993) stated that it “may sometimes 
clog water courses”. However, descriptions 
recording it “rooting at the nodes” (Lack 
1980; Beentje & Ghazanfar 2005) suggest 
that it is partly dependant on soil substrate. 
The Australian taxon is considered to be 
distinct from Enydra fluctuans , and the name 
E. woollsii is reinstated here for it. 
The distribution of Enydra fluctuans is 
markedly disjunct from that of E. woollsii. It 
is notable that E. fluctuans extends no further 
Accepted for publication 1 September 2009 
south than Java and no further east than 
Sulawesi, except for a naturalised occurrence 
in the Philippines reported by Merrill (1923). 
There is no known occurrence of Enydra in 
New Guinea (Koster 1979), nor in northern 
Queensland (Queensland Herbarium records). 
There is one specimen record at the Northern 
Territory Herbarium, collected near Darwin 
in 2002, from a plant apparently escaped from 
cultivation. 
Enydra woollsii F.Muell., Fragm. 3: 139 
(1863), as ‘ Enhydra Woollsii’. Type citation: 
“In paludibus prope Manly Beach portus 
Jacksonii. W. Woolls”. Type: New South 
Wales. Manly Beach, s.dat., W. Woolls s.n. 
(holo: MEL2159823). 
Perennial forb to 100 cm across and 20 cm 
high, terrestrial; flowering stems prostrate 
or weakly ascending, well-branched, terete, 
solid, up to 3 mm diameter, not constricted 
at the nodes, glabrous. Leaves opposite, 3.5- 
8 cm long, 0.8-1.5 cm wide, lanceolate to 
narrowly-elliptic, with conspicuously serrated 
margins (3-7 teeth per side), base cuneate or 
attenuate, apex acute; petioles 2-5 mm long. 
Lamina with numerous yellowish oil glands, 
and sometimes with a few ciliate hairs along 
the midrib. Capitula axillary, solitary, many- 
flowered, radiate, peduncles 0-2 mm long. 
Involucral bracts 4, in two opposite pairs, 
the outer ones longer than the inner. Outer 
bracts 4-10 mm long, with a longitudinal 
midvein and a network of secondary veins, 
midvein glabrous or with a few ciliate hairs, 
apex acute; paleae c. 4 mm long, sheathing 
the florets, with sessile glands on the distal 
margin; ray florets female, greenish-yellow 
to yellow, 3-lobed, zygomorphic, glandular; 
stigma bifid. Disc florets yellow, 4 or 5-lobed. 
Achenes black, narrowly obovoid but curved 
on outer surface, 2.4-27 mm long, finely 
longitudinally striate, pappus absent. 
