Solanum procumbens Lour., Fl. Cochinch. 132. 1790.

Aubriot, Xavier & Knapp, Sandra, 2022, A revision of the " spiny solanums " of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae), PhytoKeys 198, pp. 1-270 : 1

33. Solanum procumbens Lour., Fl. Cochinch. 132. 1790.

Fig. 55

Solanum hainanense Hance, J. Bot. 6: 331. 1868. Type. China. Hainan: "At vias prope Kieng chau fú, metropolis ins: Hainan", Nov 1866, Sampson & H.F. Hance s.n. [13816] (lectotype, designated here: BM [BM000942492]; isolectotype: K [K000759385]).

Solanum scopulorum Kerr ex Barnett, Kew Bull. 16: 486. 1963. Type. Thailand. Prachuap Khiri Khan: Hua Hin, 11 Nov 1928, A.F.G. Kerr 16210 (holotype: K [K000922039]; isotypes BK [BK257532], BM [BM000886111]).

Type.

Vietnam. Thua Thiên-Huê: Huê and vicinity, Jan 1923, R.W. Squires 27 (neotype, designated by Hul and Dy Phon 2014, pg. 20: P [P00054100]; isoneotypes: BM [BM000886103], E [E00224906], K [K000195689]) .

Description.

Scandent or creeping herbs or shrubs, to 2(-3) m tall, armed. Stems prostate or erect, terete, prickly and pubescent; prickles up to 1 cm long, to 1 cm at the base, more or less regularly spaced, strongly hooked but sometimes straight, flattened and deltate, pale yellow, glabrous; pubescence of sessile porrect-stellate trichomes, the rays 6-8, 0.1-0.3 mm long, the midpoints absent or <0.1 mm long; new growth sparsely to densely stellate-pubescent, green to light brownish in dry material; bark of older stems brownish grey, glabrous. Sympodial units apparently plurifoliate, the leaves not geminate. Leaves simple, entire to moderately lobed, the blades 2-6.5 cm long, 1-3.5 cm wide, ca. 1.5-2.5 times longer than wide, elliptic to ovate, sometimes obovate, chartaceous, discolorous, unarmed or with up to 5 prickles per face, these slightly smaller and thinner than the ones on the stems; adaxial surface green to dark green, evenly and sparsely pubescent with erect sessile porrect-stellate trichomes, the rays 6-8, 0.1-0.3 mm long, the midpoints to 0.1 mm; abaxial surface densely stellate pubescent with trichomes like those of the adaxial surface but with stalks up to 0.1 mm long and longer rays; major veins ca. 3 pairs drying light brownish; base attenuate; margins entire, shallowly to moderately lobed, the lobes 1-3 on each side, 0.4-1 cm long, oblong to deltate, apically rounded, the sinuses extending up to 1/3-1/2 of the distance to the midvein; apex acute to rounded; petioles 0.5-1 cm long, 1/10-1/4 of the leaf blade length, unarmed or sparsely prickly with a few curved prickles, densely stellate-pubescent, the pubescence of sessile porrect-stellate trichomes like those of the blades. Inflorescences 1.5-4 cm long, lateral or occasionally leaf-opposed, unbranched, with 4-8 flowers, 1-3 flowers open at any one time, unarmed or sparsely prickly, densely pubescent with sessile stellate-porrect trichomes like those of the stems; peduncle 0.1-1.4 cm long; pedicels 0.5-2 cm long, ca. 0.5 mm in diameter at the base and 0.5-0.75 mm in diameter at top, erect or somewhat recurved at anthesis, densely stellate-pubescent like the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 0.1-2 mm apart. Buds ovoid, exserted from the calyx before anthesis. Flowers 4(-5)-merous, apparently all perfect. Calyx with the tube 1-1.5 mm long, campanulate, the lobes 1-1.5 mm long, ca. 1 mm wide, deltate to broadly deltate, apically acute to acuminate, unarmed, densely stellate-pubescent with porrect-stellate trichomes like those of the pedicels. Corolla 1-1.5 cm in diameter, white or pale purple to deep blue, stellate, lobed ca. 3/4 of the way to the base, the lobes 5-7 mm long, 1-3 mm wide, long-triangular, spreading or reflexed at anthesis, mostly glabrous adaxially but with a few stellate trichomes on the middle vein, densely stellate pubescent abaxially on parts exposed in bud. Stamens equal or slightly unequal with 2 slightly longer than the rest; anthers 5-5.5 mm long, 1-1.5 mm wide, not connivent to somewhat spreading, all tapering, dull yellow, glabrous, poricidal at the tips, the pores not elongating to slits with drying; filament tube minute, glabrous; free portion of the filaments ca. 0.5 mm long, glabrous. Ovary conical to globular, minutely glandular-puberulent at the top; style 6-8 mm long, with few stellate trichomes scattered at the base; stigma clavate, the surfaces minutely papillose. Fruit a globose berry, several per infructescence, 0.6-1 cm in diameter, red at maturity, pericarp thin, glabrous; fruiting pedicels 1.3-1.8 cm long, ca. 1 mm in diameter at the base, 1.5-1.8 mm in diameter at the apex, erect or slightly recurved, somewhat woody, unarmed; fruiting calyx lobes ca. 2 mm long, not markedly accrescent, but covering 1/4 of the berry and not reflexed, unarmed. Seeds 5-25 per berry, 2-3 mm long, 2-3 mm wide, flattened reniform to rounded, brownish orange, the surfaces minutely pitted, the testal cells pentagonal in outline. Chromosome number: not known.

Distribution

(Fig. 56 ). Solanum procumbens is widely distributed from China and Indochina to Indonesia (Flores and Timor) and Timor Leste.

Ecology and habitat.

Solanum procumbens is a plant of open places in many forest types, often scrambling over other vegetation and on rocks, from sea level to 650(1,500) m elevation.

Common names and uses.

China. hai nan qie ( Zhang et al. 1994). Vietnam. cà gai, ( cây) cur’o’ng, trông ca dap ( Hul and Dy Phon 2014)

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (1,575,888 km2, LC); AOO (164 km2, EN). Solanum procumbens is widely distributed and occurs in many habitat types, including extremely anthropogenically disturbed ones.

Discussion.

Solanum procumbens is similar to S. trilobatum and S. camranhense in its habit as a small scrambling shrub, but in molecular analyses of Aubriot et al. (2016a) resolves as closely related to S. involucratum , a much more robust and morphologically very different plant. Solanum procumbens can be distinguished from S. camranhense in its usually 4-parted corollas, slender fruiting pedicels, and more lanceolate leaves with less truncate bases.

No specimens were cited in the protologue ( Hance 1868), so the lectotype we have selected for S. hainanense (BM00942492) is the better preserved of the two duplicates we have found and bears the Hance exsiccata number 13816.

Specimens examined.

See Suppl. materials 1-3.

Figures

Figure 55. Solanum procumbens Lour. A herbarium specimen collected in China in 1935 (Lau 5138, E 00320676) B habit (Wang et al. 2075, China) C inflorescence (Wang et al. 2075, China) D detailed view of a flower and prickles (Wang et al. 2075, China) E infructescence (Wang et al. 2075, China). Photograph credits: A Royal Botanic Garden Edinburgh B-E S. Knapp.

Figure 56. Distribution of S. procumbens.