Synonymy
Solanum johnsonianum A.R.Bean, Austrobaileya 6: 676 (2004).
T: Qld; Leichhardt District; Nirvana, c. 15 km WNW of Banana, 18 Apr. 2003, A.R.Bean 20165; holo: BRI; iso CANB, MEL, NSW. An image of the type specimen can be seen at http://delta-intkey.com/solanum/images/Sol_johns.jpg
S. nemophilum auct. non F.Muell: Symon, J. Adelaide Bot. Gard. 4: 144 (1981), p.p.
Description
Erect, rhizomatous perennial shrub, 0.15-0.3 m high. Juvenile branchlets without prickles; leaves (in outline) broadly ovate, shallowly lobed, with 2 pairs of lobes; lamina 4.5-5.5 cm long, 3.3-3.8 cm wide, without prickles on upper surface. Adult stem prickles absent. Adult branchlets grey to rusty or brown; prickles absent; stellae very dense, 0.4-0.5 mm diameter, sessile; lateral rays 7-9, porrect; central ray 3-5 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Adult leaves broadly ovate, entire; lamina 2.5-6 cm long, 1.3-4.3 cm wide, 1.4-2 times longer than broad, apex obtuse, base obtuse or cordate, oblique part 0-1 mm long, obliqueness index 0-3 percent; petioles 0.9-2.8 cm long, 30-55% length of lamina, prickles absent. Upper leaf surface green; prickles absent; stellate hairs distributed throughout; proto-stellae present; ordinary stellae dense, 0.15-0.25 mm apart, 0.25-0.35 mm across, sessile; lateral rays 7-9, porrect; central ray 3- 5 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent. Lower leaf surface greenish-white or white; prickles absent; stellae dense to very dense, 0.1-0.2 mm apart, 0.3-0.6 mm diameter, sessile; lateral rays 7 or 8, porrect; central ray 2-5 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Inflorescence supra-axillary, solitary or pseudo-racemose, common peduncle 0-2 mm long, rachis prickles absent; 1 or 2-flowered, with all flowers bisexual and 5-merous; pedicels 4-7 mm long at anthesis, same thickness throughout, c. 0.7 mm thick at mid-point, prickles absent. Calyx tube 1-3 mm long, lobes elliptic, 4-6.5 mm long; prickles absent at anthesis; stellae very dense, yellow, 0.3-0.4 mm across, sessile, lateral rays 7 or 8, central ray 3-5 times as long as laterals, not gland-tipped or gland-tipped; finger hairs absent; Type 2 hairs absent. Corolla mauve, 6-11 mm long, rotate or shallowly lobed, inner surface glabrous; anthers 3-4 mm long; ovary glabrous, or with Type 2 hairs only; functional style 5-6.5 mm long, erect, glabrous or with Type 2 hairs only.
Fruiting calyx with lobes exceeding mature fruit, prickles absent. Mature fruits 1 or 2 per inflorescence, globular, 5.5-8 mm diameter, red, 1-locular (septum absent or incomplete); placenta not apparent; mesocarp juicy, succulent; exocarp 0.3-0.5 mm thick; pedicels 10-16 mm long in fruit, 0.8-0.9 mm thick at mid-point; seeds pale yellow, 2.2-2.8 mm long.
A further detailed description of this species can be found in the Bean treatment of the eastern Australian species of Solanum at http://delta-intkey.com/solanum/www/johnsoni.htm
Distribution and ecology
A
Occurs on heavy cracking clay soils in brigalow (Acacia harpophylla), often after fire or disturbance, such as clearance.
Relationships
Treated as part of the S. densevestitum group of the subg. Leptostemonum (Bean 2004), together with S. gympiense, S. hapalum, S. innoxium, S. densevestitum, S. nemophilum and S. ultimum .
Bean (2004) considered S. johnsonianum to be most closely related to S. nemophilum and S. innoxium. It differs from the former by the lack of glandular hairs on the upper leaf surface as well as in characteristics of the stellate hairs and from the latter by wider leaves, longer petioles and sometimes by the presence of gland-tipped stellate hairs on the calyx.
Derivation of epithet
Named after Robert W. Johnson, Director of the Queensland Herbarium (1976-1990).
Selected specimens
QLD: ‘Cottenham’, c. 10 miles [16 km] NW of Banana, May 1960, R.Johnson 1708, 1709 (BRI); ‘The Rhyddings’, c. 38 km SW of Moura, Aug 1962, R.Johnson 2473 (BRI); site of Brigalow Research Station, 20 miles [32 km] NW of Theodore, Apr 1963, R.Johnson 2621 (BRI, CANB); c. 4 miles [6 km] E of Moura, Mar 1967, R.Henderson 223 (BRI). Orange Creek, c. 20 miles [32 km] NW of Biloela, Jun 1959, R.Johnson 854 (BRI); 1.6 km along
Specimens cited by Bean when first describing this species (Bean 2004).
Plant status, if any
A category of “Endangered” has been recommended since the species is only known from a few locations, is not found in conserved areas and is under threat from agricultural activities (Bean 2004).
From the web
An image of the type specimen can be seen at http://delta-intkey.com/solanum/images/Sol_johns.jpg
Further information and links for this species can be found on the Solanaceae Source site.