Synonymy

Solanum dysprosium A.R.Bean, Austrobaileya 6: 709 (2004).

T: Qld, Cape Melville NP, western slopes, 26 Nov 2001, K.R.McDonald 1026 & H.Hines; holo: BRI.

Description

Erect, rhizomatous perennial shrub, c. 0.75 m high. Juvenile stage unknown. Adult branchlets mauve or brown; prickles 25-50 per decimetre, straight, acicular, 3-8 mm long, 9-12 times longer than wide; stellae sparse, 0.25-0.5 mm diameter, stalks 0-0.1 mm long; lateral rays 4-8, porrect; central ray absent or present, 0-4 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs sparse.

Adult leaves ovate, shallowly lobed throughout; lobes 4 or 5 on each side, acute, lobing index 1.3- 1.6; lamina 7-10.5 cm long, 3.5-5 cm wide, 1.9-2.2 times longer than broad, apex acute or acuminate, base obtuse, oblique part 0-5 mm long, obliqueness index 0-6 percent; petioles 1.3-3.5 cm long, 20-35% length of lamina, prickles present. Upper leaf surface green; prickles 30-50, straight, acicular, 2-8 mm long, prickles present on midvein and lateral veins; stellate hairs distributed throughout; proto-stellae present; ordinary stellae sparse, 0.5-0.8 mm apart, 0.25-0.5 mm across, sessile; lateral rays 4 or 5, porrect; central ray 0.5-3 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent. Lower leaf surface green; prickles 11-17, straight, acicular, present on midvein and lateral veins; stellae moderate, 0.4-0.8 mm apart, 0.5-0.8 mm diameter, sessile; lateral rays 4-6, porrect; central ray 0-1 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.

Inflorescence supra-axillary, pseudo-racemose, common peduncle 17-35 mm long, rachis prickles present; 12-15-flowered, flowers 5-merous; pedicels 8-11 mm long at anthesis, same thickness throughout, 0.3-0.6 mm thick at mid-point, prickles absent. Calyx tube 2-2.5 mm long, lobes attenuate, 2-3.5 mm long; prickles absent at anthesis; stellae sparse, transparent, 0.15-0.2 mm across, sessile, lateral rays 4 or 5, central ray 1-2 times as long as laterals, not gland-tipped; finger hairs abundant; Type 2 hairs absent. Corolla purple, 10-14 mm long, shallowly or deeply lobed; anthers 5-5.8 mm long; functional style erect, glabrous.

Fruiting calyx with lobes less than half length of mature fruit, prickles absent. Mature fruits 1 per inflorescence, globular, c. 7 mm diameter; pedicels c. 15 mm long in fruit, c. 0.7 mm thick at mid-point; seeds pale yellow, 2.5-3 mm long.   

Description reproduced, with permission, from Bean, Austrobaileya 6: 709 (2004).

Another detailed description of this species by Bean can be found at http://delta-intkey.com/solanum/www/dysprosi.htm

Distribution and ecology

Known only by the type collection from Cape Melville, Cape York Peninsula where it was found in granite rocks adjacent to vine thicket.

Relationships

Similar to, and closely related to the more southerly occurring S. inaequilaterum, according to Bean (2004).

The two differ by

• the smaller leaves of S. dysprosium,
• prickles on the petioles of S. dysprosium where they are absent in S. inaequilaterum,
• a 17-35 mm long common peduncle for the inflorescence of S. dysprosium, this lacking in S. inaequilaterum and
• the calyx lobes less than 3.5 mm long in S. dysprosium while they are more than 3.5 mm long in S. inaequilaterum.

Derivation of epithet

From dysprositos, Greek for hard to get at, a reference to the difficulty in accessing the Cape Melville area, where the species is endemic.  

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Selected specimens

From the web