Solanum species of eastern and northern Australia

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A. R. Bean

Solanum argopetalum

Habit. Prostrate or sprawling, herbaceous resprouter, 0.1–0.4 m high.

Branchlets. Branchlets yellow or rusty or brown. Branchlet prickles 5–25 per decimetre, straight, acicular, 1–5 mm long, 10–17 times longer than wide, with scattered Type 2 hairs on lower half. Branchlet hairs Type 2 or stellate. Branchlet stellae dense, 0.4–0.7 mm diameter, stalks 0–0.25 mm long. Branchlet stellae lateral rays 6–11, porrect or ascending. Branchlet stellae central ray present, 1.5–3 times as long as laterals, not gland-tipped or gland-tipped, rigid. Branchlet Type 2 hairs sparse.

Leaves. Leaves broadly ovate or orbicular, entire or shallowly lobed throughout. Leaf lobes 0 on each side or 2–3 on each side, obtuse, lobing index 1–1.2. Leaves 3.5–8.5 cm long, 2–5.5 cm wide, 1.2–1.7 times longer than broad. Leaf apex obtuse, base cordate. Leaf oblique part 0–3.5 mm long, obliqueness index 0–5 percent. Petioles 1.2–3.5 cm long, 30–65% length of lamina, prickles absent.

Upper leaf surface. Upper leaf surface grey-green. Upper leaf surface prickles absent or present on midvein only, 0–2, straight, acicular, 1–3 mm long. Upper leaf surface stellate hairs distributed throughout, protostellae present, hair density sparse to moderate density. Upper leaf surface stellae 0.4–0.6 mm apart, 0.6–0.9 mm across, stalks 0–0.3 mm long. Upper leaf surface stellae lateral rays 7–10, porrect or ascending. Upper leaf surface stellae central ray 1–3 times as long as laterals, not gland-tipped or gland-tipped. Upper leaf surface simple hairs absent or erect, straight, sparse, gland-tipped, 0.1–0.3 mm long. Upper leaf surface Type 2 hairs absent.

Lower leaf surface. Lower leaf surface green or greenish-white. Lower leaf surface prickles absent. Lower leaf surface stellate hair density dense. Lower leaf surface stellae 0.1–0.2 mm apart, 0.5–0.6 mm diameter, stalks 0–0.1 mm long. Lower leaf surface stellae lateral rays 8–11, porrect. Lower leaf surface stellae central ray 1–1.5 times as long as laterals, not gland-tipped or gland-tipped. Lower leaf surface simple hairs absent. Lower leaf surface Type 2 hairs absent.

Inflorescence. Inflorescence leaf-opposed or supra-axillary, solitary or cymose (pseudo-racemose). Inflorescence common peduncle absent or present, 0–2 mm long. Inflorescence rachis prickles absent or present. Inflorescence 1–4-flowered, with some bisexual and some male flowers or all flowers bisexual. Flowers 4–5-merous. Pedicels at anthesis 3–10 mm long, same thickness throughout, 0.5–0.6 mm thick at mid-point, prickles absent. Calyx tube at anthesis 1.5–3 mm long. Calyx lobes at anthesis deltate or rostrate or attenuate, 2–7 mm long. Calyx prickles at anthesis absent. Calyx stellae dense, transparent, 0.4–0.7 mm across, stalks 0–0.2 mm long, lateral rays 6–10. Calyx stellae central ray 1–2 times as long as laterals, not gland-tipped. Calyx simple hairs absent, Type 2 hairs absent. Corolla white, 7–9 mm long, deeply lobed, inner surface glabrous. Anthers 3–4 mm long. Ovary with Type 2 hairs only. Functional style 4.5–6 mm long, protruding between anthers, with Type 2 hairs only.

Fruits. Fruiting calyx lobes less than half length of mature fruit or lobes more than half length of mature fruit, prickles absent. Mature fruits 1–3 per inflorescence, globular, c. 15 mm diameter, yellowish-green or green, often streaked, 1-locular (septum absent or incomplete). Mature fruits placenta sessile, elliptical. Mature fruits interior moist but not juicy, pericarp 1–1.5 mm thick. Pedicels at fruiting stage 8–20 mm long, 1–1.2 mm thick at mid-point. Seeds pale yellow, 2.7–3.1 mm long.

Distribution and habitat. Queensland. Qld: Maranoa. Shrubby eucalypt woodland, remote from rainforest, lancewood communities (dominated by Acacia catenulata, shirleyi, burrowii, etc.).

Miscellaneous. Subg. Leptostemonum. Data source: specimens.

Illustrations. • small flowering plant. • holotype. • plant at type locality. • popn at type locality.


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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