Species of Thismia go by the common name fairy lantern (not to be mistaken for the nodding group of Calochortus spp. from western North America, which are also referred to as fairy lanterns). The description seems apt for the glistening little flower shown in today’s photo. Thismia megalongensis lacks leaves. Its solitary orange flowers rest just above the soil’s surface, as though a fairy had set down her lantern on the forest duff for a moment. Thismia megalongensis‘ perianth is shaped like an urn (urceolate). The segments of the perianth are fused at the base, forming the lantern chamber. A 4-6 mm long bristle emerges from the tip of each outer perianth segment, creating what we can imagine as a perfect little handle for fairy hands. The comparison to a fairy lantern begins to break down once one considers other sensory descriptors of this species. When fresh, Thismia megalongensis‘ flowers smell of fungus, but aging flowers take on a decaying fish smell. Once these fishy flowers are pollinated, single, 4 mm wide fleshy fruits form. These fruits have a raised rim, forming a little bowl in which the seeds sit. The tiny seeds are likely dispersed when rain drops fall into the fruit’s bowl and splash the seeds out.
Colin Hunt was the first to collect a specimen of Thismia megalongensis. He found it growing in the Megalong Valley west of Sydney, Australia. Two other scientists, Greg Steenbeeke and Dr. Vincent Merckx, helped Hunt identify the specimen as a new species, and the three published their findings in Telopea in 2014. Thismia megalongensis grows in closed-canopied warm temperate rainforest. It is mycoheterotrophic, meaning that it obtains its energy from fungi that have mycorrhizal relationships with photosynthetic plants (more about this in the July 16 BPotD post). Many mycoheterotrophic species are very selective of the the type of fungi that they will parasitize. Thismia megalongensis‘ fungal symboint is currently unknown.
Thismiaceae was formerly placed in Burmanniaceae. Kew Botanical Garden’s Neotropikey describes the following traits that distinguish Thismiaceae from Burmanniaceae: a circumscissile perianth; 6 pendent (instead of 3 erect) stamens; and a short style far exceeded by the floral tube. The Thismiaceae are all mycoheterotrophic species that lack chlorophyll. Thismiaceae contains five genera, with Thismia containing about 50 species. It is not entirely surprising that a new species of Thismia would be found. Dančák et. al. (2013) explain that species in this genera are often rare. They have ephemeral above-grown parts, and so are easily missed. Today’s macro of Thismia megalongensis makes it easy to appreciate its glowing beauty, but this species is much less impressive when viewed from above, at a human scale. This photo of Thismia megalongensis growing in forest duff gives an idea of how difficult it would be to notice plants of this species while walking through the woods.