Solanum echinatum Brown (1810: 447)

Bean, A. R., 2012, A taxonomic revision of the Solanum echinatum group (Solanaceae), Phytotaxa 57 (1), pp. 33-50 : 35-36

Solanum echinatum Brown (1810: 447) ( Fig. 6A ).

Type:— AUSTRALIA. Northern Territory: North Island, Sir Edward Pellew Group , 16 December 1802, R. Brown s.n. [Bennett number 2681] (holotype BM! [ BM000596886 ] ; isotype MEL! [MEL12416] ).

Solanum ellipticum Brown (1810: 446) var. pannifolium A.Cunn. ex Bentham (1868: 464) . Type:— AUSTRALIA. Western Australia: Cambridge Gulf, anno 1819, A. Cunningham s.n. (lectotype BM), designated by Symon (1981: 198).

Solanum seitheae Symon (1981: 201) . Type:— AUSTRALIA. Queensland: Burke District: 116 km SW of Normanton, top of Donors Hill, 29 May 1967, D.E. Symon 4959 (holotype AD!; isotypes BRI!, CANB!, K, NSW!).

Illustration: Symon (1981: 202, 203), as S. seitheae .

Prostrate shrub 0.1–0.3 m high. Adult branchlets yellow, rusty or brown; prickles 100–660 per decimetre, straight, acicular, 1–8 mm long, 10–20 times longer than wide, glabrous; stellate hairs very dense, 0.6–0.8 mm in diameter, the stalks 0–0.8 mm long, the central ray 0.8–1.8 times as long as laterals. Adult leaves simple, the blades ovate or broadly ovate, 3.5–9.5 cm long, 2–5.5 cm wide, 1.6–2.1 times longer than broad. Upper surface grey-green, prickles absent or occasionally present, up to 12, 3– 5 mm long; stellate hairs of moderate density to very dense, 0.05–0.4 mm apart, 0.4–0.8 mm across, stalks 0–0.2 mm long, central ray 1–1.5 times as long as laterals. Lower surface white, grey or yellowish, prickles absent or occasionally present, up to 9; stellate hairs dense to very dense, spaced 0.05–0.15 mm apart, 0.6–0.9 mm diameter, the stalks 0–0.2 mm long, the central ray 1–1.5 times as long as laterals; entire or shallowly lobed with 3–4 obtuse lobes on each side, the base obtuse or auriculate, the oblique part 0–3.5 mm long, obliqueness index 0–9 percent, the apex acute; petioles 1.1–5 cm long, 25–55 % length of lamina, prickles present. Inflorescence 2–6-flowered, with common peduncle 25–38 mm long, rachis prickles present; pedicels at anthesis 3–11 mm long, prickles present; calyx tube 3–6 mm long, the lobes deltate or attenuate, 2.5–6 mm long; calyx prickles present at anthesis, 60–300 per flower, 1–3 mm long; calyx stellae very dense, yellow or rusty, 0.7–0.9 mm across, the stalks 0–1.1 mm long, the central ray 1–1.8 times as long as laterals. Corolla mauve to purple, 9–14 mm long, the inner surface glabrous; anthers 3.5–6 mm long; free part of the filaments 1.2–2.2 mm long; style 7–12 mm long, erect or strongly bent near base, eccentric, glabrous. Fruiting calyx almost closed at the apex rendering fruit almost invisible; stellate hairs greatly varying in size, some with stalks exceeding 0.8 mm long, protoprickles often present; prickles>100, 1– 8 mm long, straight, glabrous or with stellae attached near their base; pedicels 10–18 mm long. Mature fruits 1–4 per inflorescence, oblate, 15–23 mm diameter, interior moist but not juicy, the pericarp 2–2.5 mm thick; the placenta stalked, anvil-shaped. Seeds 2–2.7 mm long.

Distribution and habitat: — Solanum echinatum is widespread in the Kimberley of Western Australia, across the ‘Top End’ of the Northern Territory, and east as far as the Cloncurry and Normanton districts of Queensland ( Map 1 ). It grows in eucalypt woodland in a variety of habitats, including stony ridges, quartzite hills, sand dunes, and alluvial fans.

Phenology: — Flowers and fruits have been recorded for all months of the year.

Representative specimens examined: — AUSTRALIA. Western Australia: Hidden Island, Bucaneer Archipelago, 20 June 1982, K.F. Kenneally 8409 (CANB, PERTH); ca. 2 km N of Kununurra, adjacent to water tanks, half way up Kelly Knob, 20 February 1996, A.A. Mitchell 4232 (CANB, PERTH); 3 miles [5 km] S of Dunham River HS, 85 miles [137 km] S of Wyndham, 20 June 1967, D.E. Symon 5260 (CANB); 2 miles [3 km] NW of Theda station turn-off, 35 miles [56 km] S of Kalumburu Mission, 29 May 1971, D.E. Symon 7104 (CANB, DNA); 59 miles [94 km] S of Gibb River station, 3 June 1971, D.E. Symon 7149 (CANB).

Northern Territory: Settlement Creek, October 1923, L.J. Brass 334 (BRI, CANB); South West Island, Sir Edward Pellew group, 8 February 1976, L.A. Craven 3720 (CANB); China Wall, Nicholson River area, 5 June 1974, T.S. Henshall 275 (BRI, CANB, DNA); near Fish River gorge in China Wall, 8 June 1974, A. Kanis 1759 (CANB); N. Vanderlin Island, 26 July 1988, P.K. Latz 10771 (CANB); north of Mataranka towards Katherine, along the Stuart Highway, 14 June 1988, A.A. Munir 6239 (DNA); Jasper Gorge, 9 September 1974, J. Must 1255 (DNA); Pine Creek, 10 June 1971, D.E. Symon 7189 (BRI, CANB, DNA); 10 miles [16 km] NW of Humpty Doo, 25 September 1973, W.P. Walsh 1190 (CANB, DNA). Queensland: The amphitheatre, Oorindimindi station, SE of Cloncurry, 2 June 2003, R. Booth 3411 & D. Kelman (BRI, DNA); May Downs station, W of Mt Isa, 21 July 2004, R. Booth 3561 & D.T. Kelman (BRI, DNA); Calton Hills station, SE of Gunpowder, 23 June 2010, R. Booth 5498 & D.T. Kelman (BRI); Adels Grove, at lookout hill ca. 500m from resort, 8 June 2009, J. Halford GAQLD462 & B.F. Bush (BRI); W side of Lake Moondarra, 16 km NE of Mount Isa, 31 December 1989, P.L. Harris 432 (BRI); 60 miles [97 km] NE of Mt Isa on the road to Julius Dam, August 1974, J.M. Swan 126 (BRI, CANB).

Notes: — Solanum echinatum is most closely allied to S. lucani (see notes under that species). The fruiting calyx of this species has many long-stalked stellate hairs, often including ones that are rigid and prickle-like. S. echinatum is the most widespread species of the group, and even with the exclusion of S. wilkinsii and the new species, it remain a variable species. Careful field studies may yet distinguish taxa within the species as circumscribed here.

The type of S. seitheae matches the typical form of S. echinatum very well, with regard to prickle length and density on the branchlets and leaves, the repand leaf margins, the relative length of the petioles, the diameter and density of stellate hairs on the branchlets and leaves, the presence of long stalked stellae on the fruiting calyx. Therefore it is regarded here as being synonymous with S. echinatum .

Figures

MAP 1. Distribution of Solanum echinatum (circles); Solanum wilkinsii (triangles); Solanum medicagineum (stars).

FIGURE 6. Solanum hair types. A. section of fruiting calyx of S. echinatum showing prickles and hairs; B. section of upper leaf surface of S. rhaphiotes; C. a stellate hair from S. lucani; D. section of upper leaf surface of S. lapidosum. A from Harris 432; B from Russell-Smith 556; C from Thompson WES122; D from Fox 431. Scale bar: A = 2 mm, B = 0.3 mm, C = 0.25 mm, D = 0.3 mm.