Solanum pubescens Willd., Phytographia 1: 5. 1794.

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

35. Solanum pubescens Willd., Phytographia 1: 5. 1794.

Figs 3D , 4D , 59

Solanum calycinum Nees, Trans. Linn. Soc. London 17(1): 60. 1834. Type. India. Sin. loc., "Herb. Madr. 237", Anonymous s.n. [Wallich Catal. Suppl. n. 237] (lectotype, designated here: GZU [GZU000255511])

Solanum neesianum D.Dietr., Syn. Pl. (D. Dietrich) 1: 697. 1839, nom. illeg., non Solanum neesianum Wall. ex Nees, 1834. Type. Based on Solanum calycinum Nees

Solanum esenbeckii Steud., Nomencl. Bot. ed. 2, 2: 602. 1841, nom. illeg. superfl. Type. Based on Solanum calycinum Nees

Solanum conanthum Dunal, Prodr. [A. P. de Candolle] 13(1): 127. 1852, nom. illeg. superfl. Type. Based on Solanum calycinum Nees

Type.

Cultivated. " Habitat in Indiae hortis, arboretis solo argilloso rarius", Anonymous s.n. (lectotype, designated by Hepper 1987, pg. 369, as “type”: B [B-W04313-010]) .

Description.

Erect shrubs to 5 m tall, unarmed. Stems erect, terete, stellate-pubescent and sticky glandular; pubescence of very short-stalked multangulate trichomes mixed with sessile porrect-stellate trichomes, the multangulate trichomes with more than 10 rays, the rays 0.4-0.5 mm long, the porrect-stellate trichomes with 6-8 rays, 0.4-0.5 mm long, the midpoints to 1 mm long, all trichomes usually glandular tipped and the plants sticky; new growth densely glandular-pubescent, the trichomes tangled, soon deciduous and the stems glabrate; bark of older stems greyish white. Sympodial units plurifoliate, the leaves not geminate. Leaves simple, unlobed, the blades 2.5-12 cm long, 1.5-7 cm wide, ca. 1-1.5 times longer than wide, ovate to broadly triangular, widest in the lower third, chartaceous, more or less concolorous, unarmed, the leaves of lower stems much larger than those of distal branches; adaxial surface evenly and densely pubescent with sessile and very short-stalked porrect-stellate trichomes, the rays 4-8, to 0.5 mm long, glandular at the tips, the midpoints 2-4-celled, to 2 mm long, glandular at the tips; abaxial surface with similar porrect-stellate trichomes, but these denser especially along the veins; major veins 3-4 pairs, densely pubescent especially abaxially; base abruptly truncate to cordate, somewhat oblique; margins entire or slightly sinuate, not lobed; apex acute; petioles 1-4 cm long, 1/2 of the leaf blade length, unarmed, more densely glandular stellate-pubescent than the stems, but the trichomes of the same morphology. Inflorescences to 3 cm long, internodal and lateral, unbranched, with 5-12 flowers, only 1 or 2 flowers open at any one time, densely glandular pubescent with mixed multangulate and stellate-porrect trichomes like those of the stems; peduncle 0.3-0.5 cm long; pedicels 1.2-1.6 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, spreading at anthesis, glandular stellate-pubescent like the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 1-3 mm apart. Buds elongate ellipsoid and tapering, strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect. Calyx with the tube 2-2.5 mm long, conical, the lobes 3.5-5 mm long, ca. 1.5 mm wide, long-triangular to lanceolate, apically acute, densely stellate-pubescent abaxially with mixed glandular multangulate and porrect-stellate trichomes like those of the pedicels. Corolla 2-2.2 cm in diameter, violet or deep purple, stellate, lobed 3/4 of the way to the base, minimal interpetalar tissue present, the lobes 6-7 mm long, 4-4.5 mm wide, spreading at anthesis, mostly glabrous adaxially or with a few stellate trichomes along the petal midvein, densely stellate-pubescent abaxially with densely tangled sessile trichomes where exposed in bud, these densest at the tips. Stamens markedly unequal, with 4 short and one long and curved; long anther 7.5-9 mm long, 1-1.5 mm wide, strongly curved and tapering, short anthers 5-7 mm long, 1-1.5 mm wide, straight, all anthers yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube minute, glabrous; free portion of the filaments ca. 0.5 mm long, glabrous. Ovary conical, glabrous; style 9-10 mm long, strongly curved inwards and held adjacent to the long anther, glabrous; stigma capitate or slightly clavate, the surfaces minutely papillose. Fruit a globose berry, several per infructescence, 1-1.6 cm in diameter, orange-red when ripe, the pericarp thin and shiny, glabrous; fruiting pedicels 2.5-3.5 cm long, ca. 1.5 mm in diameter at the base, 2-2.5 mm in diameter at the apex, somewhat woody, spreading to pendent from weight of berries; fruiting calyx not accrescent, the lobes often breaking off. Seeds 20-30 per berry, 4-5 mm long, 3.5-4 mm wide, flattened reniform, yellowish or reddish brown, the surfaces minutely pitted, the testal cells with sinuate margins. Chromosome number: 2n = 24 ( Chennaveeraiah and Krishnappa 1971; Rao and Rao 1987).

Distribution

(Fig. 60 ). Solanum pubescens occurs from India to Saudi Arabia and Yemen on the Arabian Peninsula.

Ecology and habitat.

Solanum pubescens is found in a variety of dry forest types, such as thorn forest, often occurring in open areas and along roadsides, from 300 to 1,000 m elevation.

Common names and uses.

India. sonde, hucchu sonde, savadangi, cherichunda (Malayam), kaattu sundai kaai (Tamil), usthi kaai (Telugu) (https://www.flowersofindia.net). It is recorded as being used for bowel and joint pains (see https://www.flowersofindia.net).

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (996,977 km2, LC); AOO (272 km2, EN). Like many other spiny solanums in tropical Asia, S. pubescens is widely distributed in a variety of habitats, although the AOO suggests some concern, this is a common species.

Discussion.

Solanum pubescens is morphologically similar and probably closely related to S. vagum , sharing with that species zygomorphic flowers at anthesis, heteromorphic anthers and shiny berries on erect or slightly pendulous pedicels. Hepper (1987) treated material of S. vagum from Sri Lanka as S. pubescens in the "Revised Handbook to the Flora of Ceylon". Solanum pubescens differs from S. vagum in its glandular pubescence, its narrowly elliptic leaves with attenuate bases and slightly smaller, violet (rather than white) flowers. In S. pubescens the lamina of young leaves is obscured by the dense covering of glandular stellate to multangulate stalked trichomes with elongate midpoints and the leaves are described as "oily to touch" ( Singh 1988), while in S. vagum the pubescence of adaxial leaf surfaces is of very sparse sessile stellate trichomes with midpoints usually equal to the rays, and the lamina is clearly visible. The two species are sympatric in southern India.

Solanum pubescens and S. vagum share a zygomorphic androecium, with one anther distinctly longer than the rest. From herbarium sheets it appears that this difference becomes more pronounced with flower age. Post-anthesis anther expansion occurs in the unrelated S. turneroides Chodat (Brevantherum clade, see Stern et al. 2013) of southern South America. Buds of the African species S. somalense Franch. also have the anthers of more or less equal length that become different with age ( Vorontsova and Knapp 2016). This phenomenon needs study with populations in the field and lab.

The Solanaceae from Nees van Esenbeck’s personal herbarium are held in Graz at GZU ( Stafleu and Cowan 1981). The sheet in GZU is the only one we have found of the Wallich Herb. “Madras” gatherings cited in the protologue of S. calycinum . We therefore designate it (GZU000255511) as the lectotype of S. calycinum .

Dunal (1852) coined the replacement name S. conanthum for S. calycinum Nees citing "non Dunal" in reference to his own S. calycinum (= S. macrocarpon L. of Africa, the Gboma eggplant, see Vorontsova and Knapp 2016) that is a later homonym of Nees van Esenbeck’s name.

Specimens examined.

See Suppl. materials 1-3.

Figures

Figure 3. Diversity of inflorescences and flowers in tropical Asian spiny solanums A lax, spreading inflorescences and stellate flowers of Solanum violaceum (Sampath Kumar et al. 126945, India) B condensed, recurved inflorescences and stellate flowers of S. multiflorum (Sampath Kumar et al. 126950, India) C inflorescences and large stellate flowers of S. involucratum (field photograph, unvouchered, Vietnam) D inflorescences and stellate flowers of S. pubescens with unequal stamens, one long and recurved (Sampath Kumar et al. 126956, India) E large rotate flower of S. insanum with abundant interpetalar corolla tissues (Sampath Kumar et al. 126918, India) F many flowered inflorescence and infructescence of S. pseudosaponaceum (field photograph, unvouchered, Philippines) G many flowered inflorescences of S. torvum; flowers with well-developed interpetalar corolla tissues (Suksathan et al. PS 3815, Thailand) H small stellate flowers of S. viarum (Sampath Kumar et al. 126944, India). Photograph credits: A, B, D, E, H X. Aubriot C M. Nuraliev F D. Tandang G D. Pedersen.

Figure 4. Diversity of fruits and seeds in tropical Asian spiny solanums A large oval fruit of Solanum insanum (Sampath Kumar et al. 126918, India) B condensed infructescence and small rounded fruits of Solanum hovei (field photograph, unvouchered, India) C large rounded hairy fruit of S. involucratum with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) D small rounded fruit of Solanum pubescens with elongated calyx lobes (Sampath Kumar et al. 126956, India) E rounded fruit of Solanum cyanocarphium with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) F small rounded fruit of S. trilobatum in transverse cut (Meeboonya et al. RM 242, Thailand) G rounded fruit and accrescent calyx of S. praetermissum in transverse cut (field photograph, unvouchered, Vietnam) H oval fruit of Solanum virginianum in transverse cut (field photograph, unvouchered, India). Photograph credits: A, B, D, F, H X. Aubriot C, E, G M. Nuraliev.

Figure 59. Solanum pubescens Willd. A herbarium specimen collected in India (Wight 2629 b, BM 000900098) B habit (Sampath Kumar et al. 126956, India) C inflorescence (Sampath Kumar et al. 126956, India) D immature fruit (Sampath Kumar et al. 126956, India). Photograph credits: A CC-BY, © copyright The Trustees of the Natural History Museum, London B-D X. Aubriot.

Figure 60. Distribution of S. pubescens.