Solanum clarkiae Symon, J. Adelaide Bot. Gard. 4: 277; figs 124, 126 (1981)
T: 16 km SW of East Alligator River crossing on road to Oenpelli, N.T., 11 June 1967, D.E. Symon 5156; holo: CANB; iso: AD ex ADW, B,K, NSW, NT, US.
Spreading annual or biennial shrub to 1 m, bright yellow-green, densely pubescent with stellate hairs; prickles to 1 cm long, abundant on stems, pedicels and calyx, sparse or absent elsewhere.
Leaves ovate; lamina 5-10 cm long, 3-6 cm wide, concolorous, entire or almost so; petiole 2-3 cm long. Juvenile leaves with lamina up to 22 cm long, 14 cm wide, shallowly lobed, the petiole to 5 cm long.
Inflorescence of one bisexual flower below racemose cyme of up to 20 male flowers; peduncle absent or to 1 cm long; rachis to 10 cm long. Bisexual flower: pedicels 25-40 mm long; calyx 15-20 mm long, the lobes narrowly triangular, 10-13 mm long, enlarged in fruit; corolla broadly stellate, 30-45 mm diam., purple; anthers 5-7 mm long. Male flowers: pedicels 1-2 cm long; calyx 10-15 mm long, the lobes lanceolate, 8-12 mm long; corolla broadly stellate, 25-35 mm diam., purple; anthers 6-8 mm long.
Fruiting calyx lobes 25-50 mm long. Berry globular or ellipsoid, 20-30 mm diam., ivory or pale yellow, drying black. Seeds 2.5-3 mm long, black. n=12.
Distribution and ecology
Originally restricted to Wessel Islands and the northern and western escarpments of the Arnhem Land plateau, N.T. but now showing a somewhat wider distribution - see AVH generated map.
Usually at base of large rocky breakaways.
An andromonoecious species i.e. one in which there are male flowers and bisexual flowers on the one plant. Often there are many male flowers in an inflorescence with 1(-2) bisexual flowers at their base.
Andromonoecious species of the Dioicum group in Australia include S. beaugleholei, S. clarkiae, S. chippendalei, S. diversiflorum, S. eburneum, S. heteropodium, S. melanospermum, S. oedipus and S. phlomoides .
Symon (1981) indicated that S. clarkiae was closely related to S. melanospermum, an observation supported by the DNA studies of Martine et al. (2006) where these two species formed one of three clades for the andromonoecious species of the Dioicum group.However further molecular analysis involving the trnK-matK gene region has now indicated that all of the Australian andromonoecious species (except for S. campanulatum , S. cinereum and S. stupefactum ) should be combined to form a single clade which also includes two African andromonoecious species and the Australian hermaphrodite species S. hoplopetalum (Martine et al., 2009).
References: Martine, C.T., D. Vanderpool, G.J. Anderson, and D.H. Les (2006). Phylogenetic relationships of andromonoecious and dioecious Australian species of Solanum subgenus Leptostemonum section Melongena: Inferences from ITS sequence data. Systematic Botany 31: 410-420; Martine, C.T., G.J. Anderson & D.H. Les (2006). Gender-bending aubergines; molecular phylogenetics of cryptically dioecious Solanum in Australia. Australian Systematic Botany 22: 107-120.
Symon (1981) recorded this species as having an unusual biennial life cycle whereby in their first year they produce stocky, leafy plants which persist over winter and then produce flowers and fruits in their second season; the plants then die.
Derivation of epithet
Named for Mrs M. A. Clark who assisted the author of the species (David Symon) in a Solanum collecting trip in northern Australia in the 1960's.
N.T.: Elcho Island, P.K. Latz 6259 (AD, CANB, DNA, NT); 16 km from East Alligator River crossing on road to Oenpelli, D.E. Symon 7991 (BRI, NT).
Plant status, if any
Conservation status as a plant of least concern in the
From the web
According to the Fire Response Records of North Australian Land Manager, S. clarkiae in Nitmiluk NP has a life span of 1 year, seeding in this first year. It does not resprout, is mostly killed when subjected to fire and recruitment is by seed. This is at odds with the observations by Symon (see Notes above).