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a folded and fused structure. Hopkinsia and Lyginia differ strikingly from Anarthria in 
these features of vegetative morphology and anatomy. The culms have both a 
sclerenchyma cylinder and parenchyma sheath. Tire leaves are not equitant; there is a 
much reduced dorsiventral lamina, often in the form of a mucro or awn at the apex of 
the sheath. The leaf laminae of juvenile plants or those resprouting after fire are often 
less reduced, but the lamina always has dorsiventral structure. The inflorescences also 
lack a large enclosing spathe, as shown by Anarthria. All three genera possess sand¬ 
binding roots with long, persistent and lignified root hairs, but Pate and Delfs (1999) 
indicate that this character may be plesiomorphic and loss of this epidermis in many 
Restionaceae is considered to be apomorphic. 
Although the analyses of DNA data indicate a close relationship between Anarthria, 
Hopkinsia and Lyginia, if these genera lack morphological synapomorphies they fail to 
form a family with recognisable apomorphic characteristics. The paucity of 
synapomorphies is shown by the tree based on morphological data (Fig. 2), in which 
the three genera are placed ungrouped at the base of the tree. Several of the features 
that these genera share (Table 1) appear to be plesiomorphic in the Poales; these 
include the 2-lobed, 4-sporangiate anthers and pollen with graminoid-type aperture. 
The 23 characters (or character groups) listed in Table 1 reveal only the absence of silica 
in the culms as a probable synapomorphy supporting the group ( Anarthria, Hopkinsia, 
Lyginia) in contrast to Restionaceae. 
(3) One new family or two? 
Within the Anarthria clade, DNA data show ( Hopkinsia, Lyginia) as sister to Anarthria 
(Fig. 1) but, as noted above, they fail to group in trees based on analysis of 
morphological features (Fig. 2). Hopkinsia and Lyginia present very dissimilar 
morphological features, and many of the features they share are plesiomorphic. They 
share the synapomorphies of culm sclerenchyma cylinder and parenchyma sheath 
(homoplasious with conditions in Restionaceae), but these features do not 
convincingly associate them as a family in the face of many notable autapomorphies 
(Table 1). 
Distinctive autapomorphies for Hopkinsia include the thickened pedicel, long stigmatic 
branches that are themselves branched, and fruit with both fleshy and woody layers. 
Other features that are paralleled in some Restionaceae but are autapomorphic within 
the Anarthria clade are the hyaline perianth and bracts, reduced gynoecium with a 
single loculus and style, and indehiscent fruit. Linder (1992) observed that the ovary 
of Hopkinsia differs in structure from other unilocular ovaries in Restionaceae. 
Lyginia is marked by epidermal cells and stomates that are oblique to the culm surface, 
chlorenchyma of alternating blocks of thin-walled photosynthetic cells and thick- 
walled non-photosynthetic cells ('false pillar cells', not bordering substomatal cavities 
and not homologous with Restionaceous pillar cells), fused staminal filaments, unique 
seed ornamentation of cuticular spinules and a cuticular flange encircling the seed in 
the median vertical plane. 
We conclude, from the molecular and morphological evidence now available, that 
Hopkinsia, and Lyginia cannot satisfactorily be included in either Restionaceae or 
Anarthriaceae but that they do not form a single, well defined, new family. The 
families Hopkinsiaceae and Lyginiaceae are therefore here established. The situation 
is comparable to the recent recognition of two other new monocot families, 
Anemarrhenaceae and Behniaceae (Conran et al. 1997), based in part on relationships 
(oi lack of close relationship) suggested by molecular sequence data. Since the 
Hopkinsiaceae and Lyginiaceae were not recognised by Kubitzki (1998), information 
is provided here covering aspects treated for other monocot families in the Families and 
Genera of Flowering Plants vol. 4. 
