The Mysteries of Utricularia dichotoma in Coastal Victoria

The Mysteries of Utricularia dichotoma in Coastal Victoria

Throughout my travels across Victoria, I have come across some taxa within the U. dichotoma species complex that don’t quite fit the descriptions or range outlined in Jobson & Baleeiro’s 2020 review of the species. In coastal southern and eastern Victoria, U. dichotoma subsp. maritima seems to be the dominant taxon present. However, I’ve found a few sites where the bracts of the population don’t resemble that of subsp. maritima. Whether these plants represent new taxa, range extensions, hybrids or variation within the suspecies remains unknown (for now at least).

Site 1 – a creek a few km away from the Vic/NSW border

This shallow sandstone (?) creek flows steadily through heathy sclerophyll forest and seems to drain a large swamp upstream. The Utricularia grew in shallow sections of the creek, either under a few cm of water or on the waterlogged banks along with D. binata, D. spatulata and U. lateriflora. The base of the bracts has a large outwards poiting protruberance, but I’m not sure if it constitutes a spur. The lower corolla lip is much longer than the corolla spur.

The bracts of the plants at the NSW/Vic border site

Site 2 – a heathy swamp in central Gippsland

This site was a large swamp that was enclosed by heathy sand dunes and sclerophyll forest. Utricularia oppositiflora was also present here and I suspect that some of these plants might actually be hybrids due to the slight veination on the upper corolla lip and prominent ‘shoulders’. These putative hybrids are not gibbous at the base and lack bract-spurs like U. oppositiflora. The following sets of images are different views of individual specimens.

Comparison of the possible hybrid vs U. oppositiflora. More photos of U. oppositiflora at this site here.

Site 3 – A swamp amongst heathland in Central Gippsland

The plants in this swamp resembled those of site 2, although it is about 30 km away. U. australis was also at this site.

Site 4 – Swamp west of Melbourne

This swamp lies west of Melbourne and is surrounded by open woodland. It grows alongside Utricularia barkeri and plants like Spiranthes australis. The base of the bracts seem to be gibbous and attached at the base. The plants have a constricted lower corolla lip about the palate, and the upper corolla lip has very slight dark purple veins.

Possibly the same plant as above. Note that the bracts aren’t basiolute in contrast to U. barkeri.
Another specimen from site 4
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