[Botany • 2015] Thismia Hongkongensis • A New Mycoheterotrophic Species (Thismiaceae) From Hong Kong, China, With Observations On Floral Visitors And Seed Dispersal

 Thismia hongkongensis S.S.Mar & R.M.K.Saunders
Flower structure in Thismia hongkongensis sp. nov. A Mature flower, showing outer tepals (ot), inner tepals (it) and abscission zone (ab) at the base of the perianth tube. B Entire plant (S.S. Mar 1, HK).doi: 10.3897/phytokeys.46.8963
Figure 1. Flower development in Thismia hongkongensis sp. nov.
A, B Root system, with young flowering stalk developing (arrowed). C–G Developing flower, photographed over a 17-day period (10th, 14th, 16th, 19th and 23rd May, respectively) (S.S. Mar 1, HK). I, J Post-fertilization flower, showing abscission of perianth tube.
Photos by S.S. Mar. doi: 10.3897/phytokeys.46.8963
AbstractA new species, Thismia hongkongensis S.S.Mar & R.M.K.Saunders, is described from Hong Kong. It is most closely related to Thismia brunonis Griff. from Myanmar, but differs in the number of flowers per inflorescence, the colour of the perianth tube, the length of the filaments, and the shape of the stigma lobes. We also provide inferences on the pollination ecology and seed dispersal of the new species, based on field observations and interpretations of morphology. The flowers are visited by fungus gnats (Myctophilidae or Sciaridae) and scuttle flies (Phoridae), which are likely to enter the perianth tube via the annulus below the filiform tepal appendages, and exit via small apertures between the filaments of the pendent stamens. The flowers are inferred to be protandrous, and flies visiting late-anthetic (pistillate-phase) flowers are possibly trapped within the flower, increasing chances of pollen deposition on the receptive stigma. The seeds are likely to be dispersed by rain splash.
Keywords: Burmanniaceae, China, mycoheterotrophic, pollination, rain splash dispersal, Thismia, Thismiaceae, new species

Figure 3. Fruit structure in Thismia hongkongensis sp. nov.
Flower (rear right), immature fruit, shortly after fertilization (left), and mature fruit with exposed seeds (front). B Two fruiting individuals, each with three fruits.
 Photos by S.S. Mar. doi: 10.3897/phytokeys.46.8963
Figure 3. Fruit structure in Thismia hongkongensis sp. nov.
Lateral view of fruiting specimen, illustrating elongated fruit stalk. D Mature fruit with exposed seeds. E Dehydrated fruit. F Rehydrated fruit, after rainfall.
Photos by S.S. Mar. doi: 10.3897/phytokeys.46.8963
Shek Shing Mar and Richard Saunders. 2015. Thismia hongkongensis (Thismiaceae): A New Mycoheterotrophic Species from Hong Kong, China, with Observations on Floral Visitors and Seed Dispersal. PhytoKeys 46: 21-33. doi: 10.3897/phytokeys.46.8963