Solanum quadriloculatum
n = ploidy missing =12 voucher: Symon 3979 (ADW) (Randell & Symon 1976)
Solanum quadriloculatum occurs in South Australia, Northern Territory, the Kimberley of Western Australia and in Queensland; in Queensland is confined to the north-west, from Lawn Hill N.P. to Duchess, and east to Cloncurry. It inhabits low open eucalypt woodland on gravelly hills and flats.
Solanum quadriloculatum is a typical member of Solanum subgenus Leptostemonum. It is placed into the S. ellipticum group (Group 27) by Bean (2004) on morphological grounds; its phylogenetic position has not been investigated using molecular data.
Black, J.M. 1928. Additions to the flora of South Australia.
No. 26. Transactions and Proceedings of the Royal Society of South Australia 52: 225- 230.
Symon, D.E. 1981. A revision of Solanum in Australia.
J. Adelaide Bot. Gard. 4: 1-367.
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 quadriloculatum is closely related to S. ellipticum, but differs by the conspicuously ridged branchlets, the presence of long-stalked stellae (stalks > 0.4 mm long and up to 1.6 mm long) on all plant parts, the mostly larger stellae on the upper and lower leaf surfaces, the 9-15 flowered inflorescences (1-9 flowered for S. ellipticum), the flimsy (non-rigid) prickles on the calyx, and the absence of prickles on the rachis of the inflorescence. Solanum quadriloculatum fruits are consistently 4-locular, but some forms of S. ellipticum may also be 4-locular.
Solanum crassitomentosum is related to S. quadriloculatum, but differs by the 1-2 flowered inflorescence (9-15 flowered for S. quadriloculatum), calyx and leaf laminae without prickles (leaves and calyx prickly for S. quadriloculatum), inner surface of corolla densely stellate hairy (vs. glabrous for S. quadriloculatum), central ray of stellae on lower leaf surface 1.5-2 times as long as lateral rays (vs. 0.8-1.2 times for S. quadriloculatum) and the brown to black seeds (vs. pale yellow for S. quadriloculatum).
The type of S. quadriloculatum was collected from the Nicholson River at about 18o latitude. All subsequent collections of S. quadriloculatum have been made further south (19-22.5o latitude). The type (which is rather scrappy) does not match the subsequent collections terribly well. It has broad based prickles, < 10 times longer than wide, the stellae of the upper leaf surface are relatively widely spaced (moderate to dense) and the stellae stalks are very short. Collections from the type locality are sorely needed to determine if the name has been correctly applied. The full description given above is based on the modern collections.
In describing Solanum ellipticum var. duribaccalis, Black did cite a specific locality or type collection. The article in which the variety is described is entitled “Additions to the Flora of South Australia” (Black, 1928), so a neotype should be sought from collections from that area.
Conservation status: Widespread. Not considered at risk.