Solanum graniticum A.R.Bean, Austrobaileya 6: 732 (2004).
Solanum sp. (
Prostrate or sprawling, herbaceous resprouter, 0.15-0.3 m high. Juvenile stage absent. Adult branchlets yellow or brown; prickles 10-45 per decimetre, straight, acicular, 2.5-9 mm long, 10-16 times longer than wide; stellae dense, 0.25-0.5 mm diameter, sessile; lateral rays 7 or 8, porrect; central ray 0.3-0.7 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Adult leaves elliptical or ovate, shallowly to deeply lobed throughout; lobes 2 or 3 on each side, obtuse, lobing index 1.5-3; lamina 1.2-2.6 cm long, 0.6-1.3 cm wide, 1.6-2.4 times longer than broad, apex obtuse, base cuneate, oblique part 0-1 mm long, obliqueness index 0-4 percent; petioles 0.15-0.45 cm long, 13-22% length of lamina, prickles absent. Upper leaf surface green; prickles 1-3, straight, acicular, 1-5 mm long, prickles present on midvein only; stellate hairs confined to midrib, or distributed throughout; protostellae absent; ordinary stellae very sparse to sparse, 0.3-1 mm apart, 0.1-0.3 mm across, sessile; lateral rays 5-8, porrect; central ray 0.5-1 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent. Lower leaf surface green; prickles 0-2, straight, acicular, absent or present on midvein only; stellae sparse to moderate, 0.4-0.7 mm apart, 0.25-0.4 mm diameter, sessile; lateral rays 7 or 8, porrect; central ray 0.5-1.2 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Inflorescence leaf-opposed or supra-axillary, solitary or pseudo-umbellate, common peduncle 0-1 mm long; 1 or 2-flowered, strongly andromonoecious, flowers 5-merous; pedicels 9-15 mm long at anthesis, same thickness throughout, 0.4-0.6 mm thick at mid-point, prickles present. Calyx tube 2.5-3 mm long, lobes deltate or rostrate, 2-5.5 mm long; prickles present at anthesis, 18-50 per flower, 1.5-5 mm long; stellae moderate to dense, transparent, 0.2-0.3 mm across, sessile, lateral rays 6-8, central ray 0.5-1 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent. Corolla mauve, 9-14 mm long, shallowly lobed, inner surface glabrous; anthers 3.5-4.5 mm long; ovary with Type 2 hairs only; functional style 5.5-8.5 mm long, erect, with Type 2 hairs only.
Fruiting calyx with lobes less than or more than half length of mature fruit, prickles 2-5 mm long. Mature fruits 1 per inflorescence, globular, c. 15 mm diameter, green; mesocarp moist but not juicy; pedicels 15-27 mm long in fruit, 0.7-0.9 mm thick at mid-point; seeds pale yellow, 2.7-3.2 mm long.
A.R.Bean's description reproduced, with permission, from Austrobaileya 6: 732 (2004).
A detailed description of S. graniticum can also be seen in the Bean treatment of the eastern Australian species of Solanum at http://delta-intkey.com/solanum/www/granitic.htm
Distribution and ecology
Found in Qld on the mainland in the Bowen area and on adjacent
Flowering specimens collected March; fruiting specimen March and May
S. graniticum is considered by Bean (2004) to be a member of the S. hystrix group of subgen. Leptostemonum.
S. graniticum can be further distinguished from S. adenophorum by the presence of stellate hairs (lacking in S. adenophorum ), from S. pusillum by its smaller leaves and from both species by the lack of a wing on the petiole and by its mauve rather than white flowers.
Derivation of epithet
The epithet graniticum, Latin for granite, is a reference to the substrate on which this species occurs.
Plant status, if any
Known from only 4 locations, 3 of them close to each other. While it does occur in the Gloucester Island National Park most populations are threatened human activity, weeds or grazing. Bean (2004) recommended a category of “Endangered” for this species.
From the web
An image of the type specimen can be seen at http://delta-intkey.com/solanum/images/Sol_grani.jpg
Further information and links for this species can be found on the Solanaceae Source site.