Callitriche capricorni Mason (1959: 307

Lansdown, Richard V., 2022, The genus Callitriche (Plantaginaceae, Callitricheae) in Australasia and Oceania, Phytotaxa 547 (3), pp. 243-284 : 252-253

5. Callitriche capricorni Mason (1959: 307 , figs. 3, 3A).

Type: — AUSTRALIA. QUEENSLAND. Brisbane River , July 1874, F. M. Bailey s.n. (holotype: BRI 151) .

Description: —Stem and leaf scales present. Leaf bases connate. Lingulate leaves unknown, expanded submerged or floating leaves unknown, leaves of terrestrial plants spathulate or obovate, 2.0– 4.9 mm long × 0.8–2.8 mm wide, 3-nerved, sometimes with free veins on the midrib and outer side of the outer nerves, petiole 0.4–1.0 mm long. ♂ and ♀ flowers together in most leaf axils. Bracts triangular, blunt, c. 0.2 mm long, caducous. Styles erect, 0.1 mm long, caducous. Filament arising from peduncle, erect, 0.3–1.5 mm long; anthers trilocular, 0.1 mm long × 0.1 mm wide; pollen yellow. Fruit not strumose, subsessile, much wider than high, dark reddish brown to blackish when mature contrasting with pale wing, 0.5 mm long × 0.7–0.9 mm wide, broadly winged throughout.

Illustrations: — Figures 3 (a–b) and 3A(a–b) in Mason (1959); Plate 2(E–L) in Schotsman (1985c). Fig. 1e .

Recognition: — C. capricorni can be distinguished from all other Callitriche species in the region by the very small fruit which are blackish, not strumose, ± isodiametric or wider than high and clearly winged. It most closely resembles C. sonderi from which it differs in the mature fruit with faces that are convex and not strumose, as well as the short styles, although immature fruit may appear strumose.

Distribution: — C capricorni is endemic to mainland Australia, where confirmed records extend from southern Queensland to eastern Victoria ( Fig. 5 ). However, fewer than 20 records have been confirmed and there is an urgent need for field surveys to confirm the distribution of this species.

Habitats and Ecology: — C. capricorni typically occurs in seasonal wetlands. Confirmed material has been recorded from sandy soil, white powdery clay loam, rich loam and grey clays in seasonally inundated hollows, gilgai (ephemeral lakes), small creeks and erosion gullies, as well as on the margins of larger permanent standing and flowing water. It typically occurs in or near woodland characterised by species such as Acacia harpophylla F.Muell. ex Benth. (1864: 389) , Callitris glaucophylla Joy Thomps. & L.A.S.Johnson (1986: 731) , Casuarina cristata Miq. (1848: 70) , Eucalyptus camaldulensis , E. tereticornis Sm. (1795: 41) , E. woodsiana (F.M. Bailey) Brooker (2000: 137) and Lantana von Linné (1753: 626) sp. , with Alectryon diversifolius (F.Muell.) S.T. Reynolds (1987: 335) , Eucalyptus elegans A.R. Bean (2005: 113) and E. longirostrata (Blakeley) L.A.S.Johnson & K.D.Hill (1988: 509) in the north of its range. Associated species include Alternanthera Forssk. (1775: 59) sp. , Calandrinia eremaea Ewart (1931: 486) , Danthonia DC. (1805: 32) species such as D. setacea R.Br. (1810: 177) and D. caespitosa Gaudich. (1829: 408) , Elatine gratioloides A.Cunn. (1839: 26) , Eleocharis R.Br. (1810: 224–225) sp. , Euchiton sphaericus (Willd.) Holub (1974: 271) , Gratiola pedunculata R.Br. (1810: 435) , Paspalidium jubiflorum Hughes (1923: 317) , Triglochin von Linné (1753: 338) and Wahlenbergia Schrad. ex Roth (1821: 399–400) sp. , as well as grasses and sedges. 150–470 m elevation.

Notes: — C. capricorni has been subsumed within C. sonderi based on the variability of fruit in C. sonderi ( Bean 2007: 548) . However, previous authors have noted the more conspicuous wing ( Stanley and Ross 1986) and the fact that the mature fruit are not umbonate (strumose) in C. capricorni Mason (1959: 307) . The confusion appears to arise from the fact that, at least on herbarium specimens, some immature fruit of C. capricorni do appear to be strumose and the wing is less clearly defined. Comparison of mature fruit shows a clear distinction and the shape of the fruit of C. capricorni is closer to that of C. deflexa A.Braun ex Hegelm. (1864: 58) , as noted by Mason (1959: 307) than that of C. sonderi , which itself is similar to some varieties of C. peploides Nutt. (1835: 141) . A character of note which became evident in the course of work for this publication and is particularly evident on Hosking 3398, is that the leaves on the main stem of C. capricorni may be significantly larger than those of the branches and up to twice the size of the maximum recorded for those of C. sonderi . These differences are more than adequate to justify re-establishment of C. capricorni .

This is one of three species with C. muelleri and C. sonderi described by H.D. Schotsman (1985) as having a trilocular anther and based on notes accompanying specimen HO 34457, possibly also C. brachycarpa . It also resembles C. cyclocarpa , C. muelleri and C. sonderi , having the filament arising from the peduncle.

Conservation Status: — Callitriche capricorni is widespread in eastern Australia and there is no evidence of a consistent threat throughout its range, it is therefore classed as Least Concern (LC) ( IUCN 2012).

Additional material studied:— AUSTRALIA: QUEENSLAND. Gracemere , 20 August 1867 , P. O’Shanesy 115 ( MEL 276113 A); Tingoora, 21 May 1996 , A. R. Bean 10317 ( BRI AQ489204, MEL 285257 ); Brisbane, 27º 28’ S, 153º 02’ E, 20 May 1969 , D. Hockings s.n. ( BRI AQ02707 ); Durong, 9 May 2009 , A. R. Bean 28734 ( BRI AQ820937); Darling Downs, October 1978 , M. G. Lithgow s.n. ( BRI AQ264770); Condamine, 4 September 2010 , A. R. Bean 30323 ( BRI AQ821930); Brisbane, 12 August 2009 , J. P. Lahey JPL56 ( BRI AQ749802); Bendidee State Forest , 19 August 2009 , P. I. Forster PIF36006 ( BRI AQ814656); Samford, 27º 22’ 09” S, 152º 47’ 54” E, 155 m, 25 August 2013 , S. P. Phillips 2464 ( BRI AQ819810) . NEW SOUTH WALES. Casino , 26 September 1999 , A. R. Bean 15429 ( BRI AQ678279, MEL 301693 , NSW 674129 ); Brigalow Park Nature Reserve , 9 October 2010 , J. R. Hosking 3398 ( CANB 726002 , MEL 2361659 ); Macquarie Marshes, 17 August 1979 , K. Paijmans 3175 ( CANB 286090 ) . VICTORIA. Horseshoe Lagoon Flora and Fauna Reserve , 30 March 1983 , A. C. Beauglehole 70653 ( MEL 626740 ); Tocumwal, 4 June 1979 , A. C. Beauglehole 63972 ( MEL 651590 ); Junction of Goulburn and Murray Rivers, 6 December 1988 , E. Chesterfield 2516 ( MEL 1564927 ); Tallangatta, 16 May 1972 , P. Lumley 6 ( MEL 2241779 ) .

Figures

FIGURE 1. Fruits of Callitriche in Oceania and Australasia: a—C. antarctica, b—C. aucklandica, c—C. brachycarpa, d—C. brutia, e—C. capricorni, f—C. chathamensis, g—C. cyclocarpa i face on and ii end on, h—C. cycloptera, i—C. deflexa, j—C. fuliginea.

FIGURE 3. The distribution of confirmed specimens of C. brachycarpa.

FIGURE 5. The distribution of confirmed specimens of C. capricorni