Solanum tetrathecum F. Muell., Fragm. Phytogr. Austral. 2: 165 (1861)
Bean's circumscription of this species no longer includes NSW occurrences documented by Symon (1981). These are now treated under the newly described S. jucundum A.R.Bean. Some Qld collections previously treated by Symon as atypical S. tetrathecum (e.g. AD specimen of Crisp 3102) are now treated as the newly described S. cocosoides A.R.Bean.
Erect, sparingly clonal sub-shrub to 60 cm, dark green or grey-green, pubescent with stellate hairs; prickles absent, or to 1 cm long, scattered on young growth, stems and leaves.
Leaves oblong to ovate-oblong; lamina 4–6 cm long, 5–15 mm wide, sometimes larger, concolorous or discolorous, entire to slightly undulate; hairs sparse to dense on upper surface, dense on lower surface; petiole 5–15 mm long.
Inflorescence 1–5–flowered; peduncle to 10 mm long; rachis to 15 mm long; pedicels 5–10 mm long. Calyx 5–7 mm long; lobes triangular, 2–4 mm long. Corolla stellate, 20–40 mm diam., blue-purple. Anthers 5–6 mm long.
Erect, herbaceous resprouter, 0.2–0.5 m high. Juvenile stage absent. Adult branchlets grey or yellow; prickles 1–20 per dm, straight, acicular, 3–10 mm long, 6–15 times longer than wide; stellae very dense, 0.4–0.6 mm diameter, stalks 0–0.1 mm long; lateral rays 6–9, porrect; central ray absent or present, 0–1 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Adult leaves elliptical or ovate, entire; lamina 3–7 cm long, 1.1–3.2 cm wide, 2.2–3.2 times longer than broad, apex obtuse, base cuneate or obtuse, oblique part 0–3 mm long, obliqueness index 0–4 percent; petioles 0.4–2.2 cm long, 11–30% length of lamina, prickles absent. Upper leaf surface green; prickles 0–3, straight, acicular, 5–11 mm long, prickles absent or present on mid-vein only; stellate hairs confined to midrib, or distributed throughout; proto-stellae absent; ordinary stellae density very sparse to moderate, 0.4–1.6 mm apart, 0.25–0.5 mm across, sessile; lateral rays 7 or 8, porrect; central ray 0.6–1.2 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent or present throughout, 0.1–0.5 mm apart. Lower leaf surface white or yellowish; prickles absent; stellae dense, c. 0.1 mm apart, 0.4–0.7 mm diameter, stalks 0–0.1 mm long; lateral rays 7–9, porrect; central ray 0.7–1.2 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent.
Inflorescence leaf-opposed or supra-axillary, solitary or pseudoracemose, common peduncle 3–11 mm long, rachis prickles absent; 1–3-flowered, weakly andromonoecious, flowers 5-merous; pedicels 5–20 mm long at anthesis, same thickness throughout, 0.8–1.3 mm thick at mid-point, prickles absent. Calyx tube 3–4.5 mm long, lobes deltate, 1–3.5 mm long; prickles absent at anthesis; stellae very dense, yellow, 0.25–0.4 mm across, stalks 0–0.1 mm long, lateral rays 7–10, central ray 0.7–1.3 times as long as laterals, not gland-tipped; finger hairs absent; Type 2 hairs absent. Corolla mauve or purple, 8–15 mm long, deeply lobed, inner surface sparsely to densely stellate-hairy; anthers 5–7 mm long; ovary with Type 2 hairs only; functional style 8.5–12.5 mm long, erect, with stellate and Type 2 hairs, stellae 0.1–0.2 mm across, lateral rays c. 6, central ray c. 1 times as long as laterals.
Fruiting calyx with lobes less than or more than half length of mature fruit, prickles absent. Mature fruits 1 per inflorescence, globular, 12–17 mm diameter, yellowish-green or pale green with dark green streaks, 4-locular; placenta in cross-section sessile, semi-circular, or stalked, anvil-shaped; mesocarp moist but not juicy; exocarp 0.6–1.1 mm thick; pedicels 8–20 mm long in fruit, 0.8–1.3 mm thick at mid-point; seeds pale yellow, brown or black, 2.7–2.8 mm long.
Bean's description of the recircumscribed S. tetrathecum, reproduced, with permission, from Austrobaileya 6: 771 (2004).
Another description by Bean of this re-circumscribed species can also be found on the web at http://delta-intkey.com/solanum/www/tetrathe.htm
Distribution and ecology
Originally documented in the Flora of Australia as occuring predominantly in south-eastern Qld, and on the northern slopes and plains of N.S.W., in red earth, red loam, grey clay and rarely sandy loam. It was recorded as often being associated with cleared Brigalow (Acacia harpophylla), Belah (Casuarina cristata) or Eucalyptus spp.
Bean (2004) has recircumscribed this species so that it is no longer found in NSW, but is endemic to Qld. It occurs in two areas, one the Darling Downs and the other in the Kingaroy-Yarraman area. It is still recorded as occurring in Brigalow areas on heavy clay soils, occasionally from rainforest margins or Eucalyptus populnea woodland.
The AVH generated map above shows the distribution of S. tetrathecum in the old sense. It is now considered to be confined to the Darling Downs and Kingaroy-Yarraman area of Qld - other Qld occurrences are referred to S. cocosoides and NSW records to S. jucundum .
Part of the S. macoorai group of subgen. Leptostemonum according to Bean (2004).
S. tetrathecum is closely related to S. jucundum which has been newly described out of this species by Bean (2004). The two species can be distinguished by
· denser indumentum on the upper leaf surface of S. jucundum, this sparse to moderate in S. tetrathecum
· usually much longer calyx lobes (1-10 mm) of S. jucundum), these 1-3.5 in S. tetrathecum
· shrub habit reaching 1.8 m high for S. jucundum, herbaceous and 50 cm or less for S. tetrathecum
· style of S. jucundum with glandular hairs only, that of S. tetrathecum with mixed stellate and glandular hairs
Symon's (1981) circumscription of this species was much wider than that of Bean (2004). Bean's circumscription removes NSW occurrences documented by Symon to the newly described S. jucundum A.R.Bean. Some Qld collections previously treated by Symon as atypical S. tetrathecum (e.g. AD specimen of Crisp 3102) are now treated as S. cocosoides A.R.Bean.
QLD: BURNETT DISTRICT: Kingaroy, Oct 1945, Michael 2955 (BRI); ‘Kragra’, 60 km N of Chinchilla, Aug 1986, Hando (BRI); Meandu Mine, Tarong Coal, adjacent to Dobby L.A., S.F.289, Feb 1994, Forster PIF14837 & Smyrell (AD, BRI); S.F.132 Allies Creek, c. 55 km S of Mundubbera, Nov 2002, Bean 19609 (BRI, NSW). DARLING DOWNS DISTRICT: Tara, Feb 1938, White 11181 (BRI); ‘Parkhurst’ via St George, Mar 1955, Taylor (BRI); ‘Woodlands’, 38 miles [61 km] N of Bungunya, Jun 1960, Johnson 1602 (BRI); 10 miles [16 km] N of Chinchilla, May 1966, Redgen 39 (AD, CANB); ‘Dilbong’, 35 miles [56 km] WSW of Tara, May 1968, Clague (BRI); Bullock Head road, 21 km S of Hannaford, Nov 1974, Johnson 2999 (BRI); 20.5 km SE of Moonie Hwy, SE of Westmar, Nov 1999, Bean 15861 (BRI); ‘Karriba’, SW of Milmerran, Nov 1999, Bean 15889 (BRI); cnr Schwennsen’s Road & Riverglen road, N of Glenmorgan, Apr 2001, Bean 17665 & Pedley (BRI); off Lee’s Road, 17 km W of Chinchilla, Feb 2003, Bean 19964 (BRI). MORETON DISTRICT:
Specimens cited by Bean (2004).
From the web
Images of the flowers and fruits can be accesses through the Bean solanum page at http://delta-intkey.com/solanum/www/tetrathe.htm
Further information and links for this species can be found on the Solanaceae Source site.