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epicotylar rhizome developed (Pate & Meney pers. comm.; Pate & Meney 1999). The 
rhizomatous habit facilitates resprouting after fire and, with the sand-binding roots, 
serves to anchor these floodplain species which are subject to wash-aways of the 
sandy substrate. 
Phytochemistry: Hopkinsiaceae resemble some Restionaceae ( Lepyrodia and 
Sporadanthus ) in having a simple flavonol pattern but lack flavones (Williams et al. 
1997). Quercetin and isorhamnetin are reported in both Hopkinsia species; 
proanthocyanidins and flavonoid sulphates are absent. 
Distribution: one genus of two rare species on deep, seasonally moist, sandy soils, 
that are oligotrophic or somewhat saline, in the southern half of Western Australia, 
mostly near watercourses in regions of rather low rainfall. 
Systematics and relationships: since the first description of species of Hopkinsia, this 
has been included in Restionaceae. As mentioned above, DNA sequencing of the 
chloroplast genes (Briggs et al. 2000) has now given convincing evidence that 
Hopkinsia is more closely related to Anarthriaceae than to Restionaceae. 
Hopkinsiaceae possess various features considered plesiomorphic within Poales: the 
inflorescence with flowers not in spikelets, flowers with tepals not reduced in number, 
tetrasporangiate anthers, graminoid pollen, presence of flavonoids but absence of 
flavones. They differ from Restionaceae in the distinctive wiry, branching culms and 
have a unique combination of features of culm anatomy (lacking pillars, girders and 
protective cells; chlorenchyma of 3-4 layers of cells; silica absent). They share with 
Lyginiaceae, and with various other Poalean families, many features considered 
primitive in the Poales. Similarities to Lyginiaceae include the conspicuous sand¬ 
binding root-sheath of persistent, lignified, long root hairs (Pate & Meney 1999) and 
the stout styles with stigmatic branches (Linder 1992), but they differ markedly in 
habit, vegetative and floral morphology, fruits and seeds. They have none of the highly 
distinctive features of the leaves and culm anatomy of Anarthriaceae or of 
Ecdeiocoleaceae. 
Hopkinsia 
Hopkinsia W. Fitzg Western Australia Nat. Hist. Soc. 1: 33 (1904). 
Type species: H. anoectocolea (F. Muell.) D.F. Cutler 
Description and distribution: as for the family. 
Key to species 
1 Caespitose, forming large many-stemmed tussocks; rhizomes stout, 5-9 mm diam.; 
culms 35-100 cm tall, densely crowded on the rhizomes; culm internodes (3—)6—11 cm 
long; culm sheaths 2.5-3.5 cm long; 2-4 inflorescence branches arising at each upper 
no ^ e .,.. 1. H. anoectocolea 
1 Not caespitose; culms few and widely separated, arising from elongated horizontal 
or ascending rhizomes; rhizomes slender, 1.2-2.5 mm diam.; culms 15-50 cm tall; culm 
internodes 1.5-7 cm long; culm sheaths 0.7-1.5 cm long; inflorescence branches 
arising singly at upper nodes . 2. H. adscendens 
