The genus Callitriche (Plantaginaceae, Callitricheae) in Australasia and Oceania Author Lansdown, Richard V. Ardeola Environmental Services, 45 The Bridle, Stroud, Gloucestershire, UK. GL 5 4 SQ. & Honorary Research Associate, Royal Botanic Gardens, Kew, Richmond, Surrey, TW 9 3 AE text Phytotaxa 2022 2022-05-24 547 3 243 284 journal article 56760 10.11646/phytotaxa.547.3.3 deb1c3fa-44cf-4574-9b18-ec5c9881e6c5 1179-3163 6577535 3. Callitriche brachycarpa Hegelmaier (1868:115) . Type : AUSTRALIA . VICTORIA . tributary of the Plenty towards Mt Disappointment , 6 February 1853 , F . Mueller s.n. ( Lectotype [designated by Bean 2007: 547 ] STU 83916; Isolectotypes: MEL 50295 & 50296) . Description: —Stem and leaf scales present. Leaf bases connate. Lingulate leaves unknown, expanded submerged or floating leaves unknown; leaves of terrestrial plants obovate, 1.6–7.0 mm long × 0.7–5.0 mm wide, 3-nerved, sometimes with free veins from the midrib, as well as free and looped veins from the outer nerves. ♂ ♀ flowers usually in the same axil. Bracts linear, hyaline, caducous, 0.3–0.5 mm long. Styles persistent, erect, 1.2–1.5 mm long. Filament erect, 0.5–2.5 mm long; anthers 0.2–0.3 mm long × 0.2–0.3 mm wide, possibly trilocular; pollen yellow. Fruit not strumose, subsessile, wider than high, light brown to blackish when mature, 0.6–1.0 mm long × 0.8–1.3 mm wide, narrowly winged throughout. Illustrations: — Figures 4 (a–b) and 4A(a–b) in Mason (1959) . Fig. 1c . Recognition: — C. brachycarpa can be distinguished from other Callitriche species in the region by the combination of the small, unwinged, sessile fruit which is blackish when ripe, and ± isodiametric or wider than high and not umbonate, together with most leaf axils containing both ♀ and ♂ flowers. Distribution: —Native. Callitriche brachycarpa is endemic to Australia , where it occurs throughout the western lowlands and on King Island in Tasmania ( Fig. 3 ). It is also known from six locations across Victoria State ; three on the Otway Coast and three in the Port Phillip area ( Curtis and Morris 1975 , Parks Victoria 2000 , Aston 1973 ). It formerly occurred at a site subject to inundation on the northern outskirts of Melbourne ( Jeanes 1999 , Bean 2007 , Threatened Species Section 2012 ) but has apparently been lost from this site. Habitats and Ecology: — Callitriche brachycarpa occurs in creeks and rivers or in damp hollows ( Bean 2007 ), often in or near wet forest, but also in moist areas of dry sclerophyll forest and riparian scrub. It has been recorded with a range of Eucalyptus L’Hér. (1788: 18) and Olearia species , as well as species such as Acacia dealbata Link (1822: 445) , Atherosperma moschatum Labill. (1806: 74) and Nothofagus cunninghamii Oerst. (1873: 355) . There is no information available on the elevation range of C. brachycarpa . FIGURE 3 . The distribution of confirmed specimens of C. brachycarpa . FIGURE 4 . The distribution of specimens of C. brutia in Oceania and Australasia based on records held by AVH. Notes: —H.D. Schotsman took extensive notes which accompany the specimen HO 34457 suggesting that the anther of this species is trilocular. However, this requires confirmation based on fresh material. Conservation Status: — Callitriche brachycarpa is very poorly-known throughout its range, with no recent data on the conservation status of populations. It is therefore classed as Data Deficient. Additional material studied :— AUSTRALIA : TASMANIA . s.d., s.coll. s.n. ( NSW 33820); Gippsland , February 1877 , F . von Mueller 250 ( NSW 33821); Nr. Martin , 1881 , F . von Mueller s.n. (G); Picton River December 1903 , L . Rodway s.n. ( HO 72958 , HO 8145 ); Kindred , January 1910 , L . Rodway 250 ( HO 72956 , HO 8147 ); Forth River , December 1911 , L . Rodway s.n. ( HO 34457 , HO 72959 ); Fisherman’s Varna Bay , 25 January 1984 , A . M . Buchanan 2773 ( HO 83798 ); Jackeys Creek , 2 March 1986 , A . Moscal 12540 ( HO 403083) .