Solanum species of eastern and northern Australia

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A. R. Bean

Solanum ditrichum

Habit. Prostrate or sprawling, herbaceous resprouter, 0.1–0.6 m high.

Branchlets. Branchlets brown or green. Branchlet prickles 80–180 per decimetre, straight, acicular, 1–7 mm long, 10–17 times longer than wide, glabrous. Branchlet hairs simple or stellate. Branchlet stellae sparse to moderate, 0.5–0.6 mm diameter, stalks 0–0.1 mm long. Branchlet stellae lateral rays 5–8, porrect. Branchlet stellae central ray 0.7–1.5 times as long as laterals, not gland-tipped, rigid. Branchlet simple hairs erect, straight, gland-tipped, 0.1–0.7 mm long.

Leaves. Leaves ovate or broadly ovate, shallowly lobed throughout. Leaf lobes 3–6 on each side, acute, lobing index 1.2–1.4. Leaves 6–12.5 cm long, 4.5–9.5 cm wide, 1.3–1.8 times longer than broad. Leaf apex acute, base obtuse or cordate. Leaf 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. Upper leaf surface green. Upper leaf surface prickles present on midvein and lateral veins, 15–100, straight, acicular, 2–8 mm long. Upper leaf surface stellate hairs distributed throughout, protostellae absent, hair density very sparse to sparse. Upper leaf surface stellae 0.8–1.7 mm apart, 0.3–0.4 mm across, stalks 0 mm long. Upper leaf surface stellae lateral rays 4–7, porrect. Upper leaf surface stellae central ray 2–3 times as long as laterals, not gland-tipped. Upper leaf surface simple hairs erect, straight, sparse, not gland-tipped or gland-tipped, 0.1–0.6 mm long. Upper leaf surface Type 2 hairs absent.

Lower leaf surface. Lower leaf surface green. Lower leaf surface prickles present on midvein and lateral veins, 30–100, straight, acicular. Lower leaf surface stellate hair density sparse to moderate. Lower leaf surface stellae 0.4–1.5 mm apart, 0.5–0.7 mm diameter, stalks 0 mm long. Lower leaf surface stellae lateral rays 4–8, porrect. Lower leaf surface stellae central ray 1–1.7 times as long as laterals, not gland-tipped. Lower leaf surface simple hairs erect, straight, sparse or moderate to dense, gland-tipped, 0.1–0.6 mm long. Lower leaf surface Type 2 hairs absent.

Inflorescence. Inflorescence supra-axillary, cymose (pseudo-racemose). Inflorescence common peduncle 2–16 mm long. Inflorescence rachis prickles present. Inflorescence 2–5-flowered, with some bisexual and some male flowers. Flowers 5-merous. Pedicels at anthesis 5–18 mm long, markedly thicker distally, 0.4–1 mm thick at mid-point, prickles present. Calyx tube at anthesis 3–5 mm long. Calyx lobes at anthesis deltate or attenuate, 4–8 mm long. Calyx prickles at anthesis present, 36–70 per flower, 2–7 mm long. Calyx stellae very sparse to sparse or moderate, transparent, 0.4–0.5 mm across, stalks 0 mm long, lateral rays 4–8. Calyx stellae central ray 1–1.5 times as long as laterals, not gland-tipped. Calyx simple hairs present, Type 2 hairs absent. Corolla mauve or purple, 9–17 mm long, rotate or campanulate, inner surface glabrous. Anthers 4–5 mm long. Ovary glabrous or with Type 2 hairs only. Functional style 9–10.5 mm long, strongly bent near base, not touching anthers, glabrous.

Fruits. Fruiting calyx lobes less than half length of mature fruit, prickles 2–7 mm long. Mature fruits 1–2 per inflorescence, globular, 21–26 mm diameter, yellowish-green or green, often streaked, 2-locular. Mature fruits placenta stalked, anvil-shaped. Mature fruits interior moist but not juicy, pericarp 2.5 mm thick. Pedicels at fruiting stage 15–28 mm long, 1.3–2 mm thick at mid-point. Seeds pale yellow, 2.3–2.6 mm long.

Distribution and habitat. Queensland, New South Wales. Qld: Moreton, Darling Downs, Wide Bay, Burnett. NSW: North Coast, Northern Tablelands. Evergreen notophyll rainforest (no eucalypts), wet eucalypt forest with rainforest understorey, or rainforest margins.

Miscellaneous. Subg. Leptostemonum. Data source: specimens.

Illustrations. • fruits. • flower. • habit. • holotype. • branchlet showing simple hairs. • flowers.


Cite this publication as: ‘Bean, A.R. 2012 onwards. Solanum species of eastern and northern Australia. Version: 29th June 2013. http://delta-intkey.com’.

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