Synonymy
Solanum ditrichum A.R.Bean, Austrobaileya 6: 721 (2004).
T: NSW, Branch road,
Solanum sp. (Mt Maroon P.I.Forster PIF11564), Henderson, Names Distrib. Qld Plants (2002).
Description
Prostrate or sprawling, herbaceous resprouter, 0.1-0.6 m high. Juvenile stage absent. Adult branchlets green; prickles 80-180 per decimetre, straight, acicular, 1-7 mm long, 10-17 times longer than wide; stellae sparse, 0.5-0.6 mm diameter, stalks 0-0.1 mm long; lateral rays 5-8, porrect; central ray present, 0.7-1.5 times as long as laterals, not gland-tipped; finger hairs abundant, gland-tipped, 0.1-0.7 mm long; Type 2 hairs absent.
Adult leaves ovate or broadly ovate, shallowly lobed throughout; lobes 3-6 on each side, acute, lobing index 1.2-1.4; lamina 6-12.5 cm long, 4.5-9.5 cm wide, 1.3-1.8 times longer than broad, apex acute, base obtuse or cordate, oblique part 1-10 mm long, obliqueness index 2-11 percent; petioles 2-5.6 cm long, 20-50% length of lamina, prickles present. Upper leaf surface green; prickles 15-100, straight, acicular, 2-8 mm long, prickles present on mid-vein and lateral veins; stellate hairs distributed throughout; proto-stellae absent; ordinary stellae sparse, 0.8-1.7 mm apart, 0.3-0.4 mm across, sessile; lateral rays 4-7, porrect; central ray 2-3 times as long as laterals, not gland-tipped; finger hairs present, 0.4-1.2 mm apart, not gland-tipped or gland-tipped, 0.1-0.6 mm long; Type 2 hairs absent. Lower leaf surface green; prickles 30-100, straight, acicular, present on mid-vein and lateral veins; stellae sparse to moderate, 0.4-1.5 mm apart, 0.5-0.7 mm diameter, sessile; lateral rays 4-8, porrect; central ray 1-1.7 times as long as laterals, not gland-tipped; finger hairs present, 0.3-1 mm apart, gland-tipped, 0.1-0.6 mm long; Type 2 hairs absent.
Inflorescence supra-axillary, pseudo-racemose, common peduncle 2-16 mm long, rachis prickles present; 2-5-flowered, weakly andro-monoecious, flowers 5-merous; pedicels 5-18 mm long at anthesis, markedly thicker distally, 0.4-1 mm thick at mid-point, prickles present. Calyx tube 3-5 mm long, lobes deltate or attenuate, 4-8 mm long; prickles present at anthesis, 36-70 per flower, 2-7 mm long; stellae sparse, transparent, 0.4-0.5 mm across, sessile, lateral rays 4-8, central ray 1-1.5 times as long as laterals, not gland-tipped; finger hairs present; Type 2 hairs absent. Corolla purple, 9-17 mm long, rotate, inner surface glabrous; anthers 4-5 mm long; ovary glabrous, or with Type 2 hairs only; functional style 9-10.5 mm long, sigmoid, glabrous.
Fruiting calyx with lobes less than half length of mature fruit, prickles 2-7 mm long. Mature fruits 1 or 2 per inflorescence, globular, 21-26 mm diameter, yellowish-green or pale green with dark green streaks, 2-locular; placenta in cross-section stalked, anvil-shaped; mesocarp moist but not juicy; exocarp c. 2.5 mm thick; pedicels 15-28 mm long in fruit, 1.3-2 mm thick at mid-point; seeds pale yellow, 2.3-2.6 mm long.
Bean's original description in Austrobaileya 6: 721 (2004), reproduced with permission.
Another detailed description of this species by Bean can be found in his interactive key to eastern Australian Solanum species at http://delta-intkey.com/solanum/www/ditrichu.htm
Distribution and ecology
Occurs from Mt Mee in SE Qld to Dungog in NE NSW where it occurs in eucalypt forest or on margins of rainforests.
Relationships
Closest to S. campanulatum but differing from that species by
- its acute rather than rounded leaf lobes
- calyx less than half length of fruit
- stellate hairs rarely present on branches
- more northerly distribution. S. campanulatum occurs in the
Considered by Bean (2004) to be a member of the S. hystrix group of subgen. Leptostemonum. Since molecular studies by Levin (2006) do not support this placement of S. campanulatum, it may be that S. ditrichum should also not be included here.
Derivation of epithet
The specific epithet ditrichum is from di- Greek for two, and trichos, Greek for hair, and is a reference to the two sorts of hairs present on the leaves, in this case stellate and simple eglandular hairs.
Selected specimens
Specimens cited in Bean (2004).
From the web
Images of immature fruits, hairs on the stem, and the type specimen can be accessed on the web through the description of this species by Bean at http://delta-intkey.com/solanum/www/ditrichu.htm
Further information and a herbarium specimen of this species in NSW can be seen on the PlantNET site.
Further information, images and links for this species can be found on the Solanaceae Source site.