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Telopea 8(4): 2000 
Description of Hopkinsiaceae and revision of Hopkinsia 
Hopkinsiaceae B.C. Briggs & L.A.S. Johnson, fam. nov. 
Herbae dioeciae, perennes, rhizomatosae; culmi compressi, marginibus scabris; folia 
dorsiventralia, reducta, vaginiformia; flores tepalis 6, scariosis; flores masculini 
staminibus 3; antherae bilobatae, dorsifixae, sporangiis 4, utroque lobo per rimam 
longitudinalem dehiscentes; filamenta antherarum discreta; grana pollinium aperturis 
angustis; flores feminei ovario uniloculari et stylo unico; ovulum unicum; fructus 
parva drupa. 
Type and only genus: Hopkinsia W. Fitzg. 
Perennial, glabrous, dioecious herbs with sympodial growth of rhizomes and culms; 
caespitose with short rhizomes and forming large dense tussocks, or with long 
rhizomes and forming diffuse patches of widely separated culms. Rhizomes covered 
by appressed scales. Culms branched, smooth and terete near the base, becoming 
flattened and concavo-convex above, with scabrous lateral margins. Leaves not 
caducous, consisting of a sheath with a linear reduced lamina; sheath split to the base, 
scarious, margins membranous; auricles scarious or membranous. Inflorescence 
bracts: lower ones similar to culm sheaths but smaller, the uppermost hyaline. Flowers 
wind-pollinated, not in spikelets, each in the axil of a membranous bract, not 
dorsiventrally or laterally compressed; perianth of 6 membranous tepals in two 
whorls. Male flowers: stamens 3, opposite the inner tepals; filaments free; anthers 
dorsifixed, exserted, apically notched, 2-lobed, 4-thecate, latrorse, each lobe apiculate 
and dehiscing by a longitudinal slit; the lobes attached below the midpoint to the 
connective which is c. V 5 as long as anther; spirally twisted after dehiscence; pistillode 
absent. Female flowers lacking staminodes; ovary superior, shortly stipitate, 1-locular, 
not angled; the style single, stout, densely covered adaxially (except for a narrow 
adaxial groove, i.e. stigma double-crested) by long stigmatic branches that are 
branched and papillose, style attachment slightly excentric; the ovule solitary, 
pendulous, orthotropous, bitegmic and tenuinucellate. Fruit a globose or elliptic small 
drupe with a thin fleshy outer pericarp and a hard inner pericarp (although indehiscent 
the slightly thickened and pale carpel margins are discernible and readily separable on 
dissection); shed with a short fleshy pedicel and bracts and perianth attached. 
Vegetative structure and anatomy: the culms are the main photosynthetic organs of 
the plants and resemble those of Restionaceae in general structure (Cutler 1969; 
Gilg-Benedict 1930; Cheadle & Kosaki 1975; Pate & Meney 1999; Meney, Pate & 
Hickman 1999). The culm epidermis is tanniniferous and heavily thickened on the 
outer wall; stomates are sunken, overarched by cuticular projections of epidermal 
cells; substomata 1 cavities extend deeply into the chlorenchyma. The chlorenchyma 
consists of 3-4 layers of short palisade cells with little or no development of pegs; 
pillar cells, protective cells and sclerenchyma girders are absent. To the inside of the 
chlorenchyma is a parenchyma sheath, l(-2) cells thick, surrounding the strongly 
developed sclerenchyma cylinder. The outer vascular bundles are small and 
embedded in the sclerenchyma, the inner bundles are larger with narrow 
sclerenchyma sheaths. The central tissue is parenchymatous with patches of thin- 
walled cells but no central cavity. Silica is apparently absent. The roots are sand¬ 
binding with a dense covering of persistent root hairs. The anatomy of rhizomes and 
roots is illustrated by Meney, Pate and Hickman (1999). 
Inflorescence and flower structure: inflorescences are (in the terminology of Briggs & 
Johnson 1979) blastotelic (not terminated by a flower) and anauxotelic (axes not 
growing on after flowering) as described for Restionaceae by Kircher (1986). 
