Solanum argopetalum A.R.Bean, Austrobaileya 6: 749 (2004)
T: Qld, near "Boxleigh", c. 60 km NE of St George, 24 Apr 2001, A.R.Bean 17644 & L.Pedley; holo: BRI; iso: AD, CANB, K, MEL, MO, NSW, PRE. An image of the holotype can be accessed at http://delta-intkey.com/solanum/images/Sol_argop.jpg
Prostrate or sprawling, herbaceous resprouter, 0.1-0.4 m high. Juvenile branchlets with 50-100 prickles per dm, 2-5 mm long; leaves (in outline) broadly ovate, shallowly-lobed, with 2-4 pairs of lobes; lamina c. 5 ? 4.5 cm, with 20-40 prickles on upper surface. Adult branchlets yellow, rusty or brown; prickles 5-25 per decimetre, straight, acicular, 1-5 mm long, 10-17 times longer than wide; stellae dense, 0.4-0.7 mm diameter, stalks 0-0.25 mm long; lateral rays 6-11, porrect or ascending; central ray present, 1.5-3 times as long as laterals, not gland-tipped or gland-tipped; finger hairs absent; Type 2 hairs sparse.
Adult leaves broadly ovate or orbicular, entire or shallowly lobed throughout; lobes 2 or 3 on each side, obtuse, lobing index 1-1.2; lamina 3.5-8.5 cm long, 2-5.5 cm wide, 1.2-1.7 times longer than broad, apex obtuse, base cordate, 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 grey-green; prickles 0-2, straight, acicular, 1-3 mm long, prickles absent or present on midvein only; stellate hairs distributed throughout; protostellae present; ordinary stellae density moderate, 0.4-0.6 mm apart, 0.6-0.9 mm across, stalks 0-0.3 mm long; lateral rays 7-10, porrect or ascending; central ray 1-3 times as long as laterals, not gland-tipped or gland-tipped; finger hairs absent or present, 0.3-0.6 mm apart, glandtipped, 0.1-0.3 mm long; Type 2 hairs absent. Lower leaf surface green, or greenish-white; prickles absent; stellae dense, 0.1-0.2 mm apart, 0.5-0.6 mm diameter, stalks 0-0.1 mm long; lateral rays 8-11, porrect; central ray 1-1.5 times as long as laterals, not gland-tipped or gland-tipped; finger hairs absent; Type 2 hairs absent.
Inflorescence leaf-opposed or supra-axillary, solitary or pseudo-racemose, common peduncle 0-2 mm long, rachis prickles absent or present; 1-4-flowered, weakly andromonoecious or with all flowers bisexual, flowers 4 or 5-merous; pedicels 3-10 mm long at anthesis, same thickness throughout, 0.5-0.6 mm thick at mid-point, prickles absent. Calyx tube 1.5-3 mm long, lobes deltate, rostrate or attenuate, 2-7 mm long; prickles absent at anthesis; stellae dense, transparent, 0.4-0.7 mm across, stalks 0-0.2 mm long, lateral rays 6-10, central ray 1-2 times as long as laterals, not gland-tipped; finger 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, erect, with Type 2 hairs only.
Fruiting calyx with lobes less than or more than half length of mature fruit, prickles absent. Mature fruits 1-3 per inflorescence, globular, c. 15 mm diameter, yellowish-green or green, 1-locular (septum absent or incomplete); placenta in cross-section sessile, elliptical; mesocarp moist but not juicy; exocarp 1-1.5 mm thick; pedicels 8-20 mm long in fruit, 1-1.2 mm thick at midpoint; seeds pale yellow, 2.7-3.1 mm long.
Reproduced, with permission, from Bean (2004).
Another detailed description of this species can be seen on the Bean interactive key site at http://delta-intkey.com/solanum/www/argopeta.htm
Distribution and ecology
Found in the Maranoa District of southern Qld in the area between Mungallala and the Thornby Range, SE of Surat.
The few populations known are all from disturbed sites in association with Acacia catenulata, Eucalyptus malanophloia and Phebalium glandulosum.
Apparently close to S. crassitomentosum according to Bean (2004), sharing with it short prickles, unarmed calyx and small flowers but differing by its lobed leaves, white corolla and often gland-tipped stellate hairs.
Both species were considered by Bean (2004) to be members of the S. ellipticum group of subgen. Leptostemonum.
Derivation of epithet
From the Greek argos, white and petalos, petals, a reference to the consistently white corolla of this species (Bean 2004).
QLD: MARANOA DISTRICT: 8 km E of Mungallala, Mar 1960, Johnson 1483 (BRI); near ‘Boxleigh’, c. 60 km NE of St George, Apr 2001, Bean 17643 & Pedley (BRI); 1.1 km W of ‘Eulorel’, W of Surat, Aug 2001, Bean 17747 (BRI, MEL); ‘Boxleigh’, S of Surat, Aug 2001, Bean 17761 (BRI); SW of ‘Boxleigh’, S of Surat, Aug 2001, Bean 17768 (BRI); ‘Glen Fosslyn’, SW of Glenmorgan, Jan 2002, Bean 18368 (BRI); 54 km from Mitchell towards Bollon, Jan 2002, Bean 18406 (BRI).
Cited by Bean (2004).
Plant status, if any
S. argopetalum was only known from 4 locations, none of then within a conservation reserve and it was threatened by land clearance and weeds (Bean 2004). He recommended the category of “Vulnerable”.
From the web
Images of this species, including the type specimen, can be accessed through the description in Bean's interactive key to the eastern Australian species of Solanum at http://delta-intkey.com/solanum/www/argopeta.htm
Further information and links for this species can be found on the Solanaceae Source site.