Flora of New Zealand Series

Type sp.: H. australis Diels.

Fls minute, crowded within 2–(4) hyaline floral bracts, ♂ and ♀ on separate scapes. ♂ with 2-celled anther. ♀ stipitate, styles ∞, unequal, filiform, septate. Minute annual herbs. Lvs ∞, all radical, filiform. Flowering stems ∞, terminal, < to occ. = lvs. Three spp., two in West Australia, the N.Z. sp. endemic.

Hutchinson (Fam. Flow. Pl. 1959, 700) united Hydatella and Trithuria Hook. f. (1858) under Juncella F. Muell. Black (Fl. S. Aust. 1943, 177) pointed out that Juncella was based on "Juncella tasmanica a name published by Mueller in his 2nd Gen. Rep. 1854, without any description of genus or species"; but in 1888, Hieronymus gave a full generic description (Juncella F. Muell. ex Hieron.  in Pflanzenfam. ed. 1, 2, pt 4, 1888, 15) citing as a synonym the earlier validly published name Trithuria Hook. f.

Edgar in N.Z. J. Bot. 4, 1966, 157 summarizes the differences between Hydatella and Trithuria and concludes that the two genera are distinct.

Fig. 15. HYDATELLA. H. inconspicua : leaf, × 2½; male flower; male inflorescence, × 6; female inflorescence, × 6; female flower. © All rights reserved. [Image: 4X26]