Solanum serpens
Not known
Solanum serpens is found from Mt. Tamborine in Queensland to Byron Bay in N.S.W., although the Byron Bay population is probably extinct. It inhabits notophyll rainforest on fertile loams or clay-loams, especially where there are canopy gaps. It is endemic to the area formerly covered by the Tweed Shield Volcano, centered on the plutonic complex of Mount Warning.
Solanum serpens is a typical member of Solanum subgenus Leptostemonum. It is placed into the S. macoorai group (Group 27B) by Bean (2004) on morphological grounds; its phylogenetic position has not been investigated using molecular data. Bean (2002) postulates that it is most closely related to S. acanthodapis. While it does not appear to be closely related to any other species, if has some affinity to a fairly large group of species that includes S. furfuraceum, S. tetrathecum, and S. ellipticum (Bean, 2002).
Bean, A.R. 2002. New prostrate taxa in Solanum subg. Leptostemonum (Dunal in DC.) Bitter (Solanaceae) from eastern Australia.
Austrobaileya 6(2): 247-52.
Bean, A.R. 2004. The taxonomy and ecology of Solanum subg. Leptostemonum (Dunal) Bitter (Solanaceae) in Queensland and far north-eastern New South Wales.
Austrobaileya 6 (4): 639-816.
Solanum serpens is one of three Australian species that exhibit a unique prostrate and stoloniferous habit, with long runners rooting at the nodes and sporadic erect shoots. The color and density of indumentum on the lower leaf surface is uniform within populations but can vary between localities. Solanum serpens at the type locality has an extremely dense white tomentum, whereas in specimens from Nicholls Scrub and Byron Bay, the tomentum is rusty and less dense.
Solanum serpens is rather variable in morphology, and intermediate forms with S. acanthodapis exist (Bean, 2002). Solanum acanthodapis differs from S. serpens by: stellate hairs (on all parts) with short central rays (vs. very long central ray for S. serpens); upper leaf surface (excluding veins) glabrous even on developing leaves; lateral veins somewhat raised on upper leaf surface; ovary glabrous or with stipitate glandular hairs only (vs. stipitate glandular hairs and stellate hairs for S. serpens).
Etymology: The specific epithet is from the Latin serpens, meaning creeping or snake-like. This refers to the long trailing stems.
Conservation status: It is known from several locations, some of which are on protected land. No conservation status is recommended at this time.