Solanum pseudosaponaceum Blume, Bijdr. Fl. Ned. Ind. 13: 702. 1826.

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

34. Solanum pseudosaponaceum Blume, Bijdr. Fl. Ned. Ind. 13: 702. 1826.

Figs 3F , 57

Solanum inaequilaterale Merr., Philipp. J. Sci. 1, Suppl. 236. 1906. Type. Philippines. CAR: Luzon, Benguet Province, Suyse to Panai, Oct 1905, E.D. Merrill 4807 (lectotype, designated here: US [00027616, acc. # 710478]; isolectotypes: K [K000195913], NY [00172282]).

Solanum torvum Sw. var. lasiostylum Y.C.Liu & C.H.Ou, Quart. J. Chinese Forest. 7(4): 151. 1974. Type. Taiwan. Sin. loc., "In southern parts at low altitudes", 1 Apr 1971, Y.C. Liu & C.H. Ou 540 (holotype: TCF).

Solanum lasiostylum (Y.C.Liu & C.H.Ou) Tawada, J. Phytogeogr. Taxon. 27(1): 36. 1979. Type. Based on Solanum torvum Sw. var. lasiostylum Y.C.Liu & C.H.Ou.

Type.

Indonesia. Java: Sin. loc., C.L. Blume s.n. (lectotype, designated here: GZU [GZU000255455]; isolectotypes: L [L0003669, L0003670]) .

Description.

Erect shrub to small tree to 8 m tall, armed. Stems erect, terete, prickly, usually densely stellate-pubescent; prickles to 5 mm long, to 5 mm wide at the base, straight to slightly curved, deltate, laterally flattened, pale yellow, glabrescent; pubescence of mixed sessile and variously stalked porrect-stellate trichomes, the stalks to 0.25 mm long, the rays 5-8, 0.25-0.5 mm long, the midpoints absent or up to 0.25 mm long; new growth densely stellate-pubescent with a whitish pubescence, bark black; bark of older stems brownish grey to black, glabrescent. Sympodial units difoliate to plurifoliate, the leaves not geminate. Leaves simple, entire to deeply lobed, the blades 8-17 cm long, 3.5-10.5 cm wide, ca. 1.5-3 times longer than wide, elliptic to ovate, chartaceous, strongly discolorous, unarmed or prickly with 1-6 prickles per leaf side, to 6 mm long, to 1.5 mm wide at the base, straight, awl-shaped, conical, pale yellow, glabrous; adaxial surface dark green, usually sparsely stellate-pubescent to glabrescent, sometimes moderately stellate-pubescent (e.g., Elmer 12879), the stellate trichomes porrect, sessile or stalked, the stalks to 0.25 mm long, the rays 4-9, 0.25-0.75 mm long, the midpoints to 0.5 mm long; abaxial surface light yellowish green, densely stellate-pubescent with trichomes like those of the adaxial surface, but more often stalked; major veins 5-7 pairs drying yellow; base short-attenuate to truncate; margins entire or shallowly to deeply lobed, the lobes 1-5 on each side, 0.5-4.5 cm long, deltate, rounded to apically acute, the sinuses extending up to 2/3 of the distance to the midvein; apex acute; petiole 1.5-4 cm long, 1/5-1/3 of the leaf blade length, moderately to densely stellate-pubescent with porrect, sessile trichomes like those of the blades, unarmed or prickly with 1-3 prickles like those of the stems. Inflorescences 3-5.5 cm long, apparently lateral, forked to 3 times branched, with ca. 10-40 flowers, 1-8 flowers open at any one time, densely stellate-pubescent with porrect trichomes like those of the stems, unarmed; peduncle 0.5-1.5 cm long, unarmed; pedicels 0.7-0.8 cm long, ca. 0.75 mm in diameter at the base, ca. 0.75 mm in diameter at the apex, erect, unarmed, densely stellate-pubescent with porrect trichomes like those of the inflorescence axes, articulated at the base; pedicel scars spaced 0.5-2 mm apart. Buds ovoid to ellipsoid, strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect. Calyx with the tube 0.5-0.75 mm long, campanulate, the lobes 1-1.5 mm long, 0.5-0.75 mm wide, deltate, apically acute to acuminate, unarmed and densely stellate-pubescent abaxially with trichomes like those of the pedicels. Corolla 1-1.5 cm in diameter, purple, stellate, lobed ca. 1/2-3/4 of the way to the base, the lobes 4-7 mm long, 2-4 mm wide, deltate, spreading at anthesis, adaxially glabrous but with a few stellate trichomes at the lobe tips, densely stellate-pubescent abaxially on parts exposed in bud. Stamens equal; anthers ca. 5 mm long, ca. 1 mm wide, tapering, yellow, connivent, glabrous, poricidal at the tips, the pores not lengthening to slits with age; filament tube ca. 1 mm long, glabrous; free portion of the filaments 0.5 mm long, glabrous. Ovary globose, with minute glandular hairs and few stellate hairs in the lower half; style 7-8 mm long, slender, curved at the apex, densely stellate pubescent in the lower half; stigma capitate, minutely papillate. Fruit a globose berry, several to many per infructescence, 0.7-1 cm in diameter, the pericarp smooth, thin, red when mature, glabrous; fruiting pedicels 1-1.5 cm long, 1 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, woody, erect, unarmed; fruiting calyx lobes expanding to 2.5 mm long, 1/3 the length of the mature fruit, broadly deltate, reflexed, unarmed. Seeds 25- -more than 100 per berry, 2-3 mm long, 1.5-2 mm wide, flattened-reniform, dull yellow, the surface minutely pitted, the testal cells sinuate in outline. Chromosome number: not known.

Distribution

(Fig. 58 ). Solanum pseudosaponaceum is widely distributed from South China (Fujian, Guangdong, Hainan provinces), Taiwan and Ryukyu Islands of southern Japan to the Philippines, Indonesia (Sulawesi, Java) and Indochina (Cambodia, Laos).

Ecology and habitat.

Solanum pseudosaponaceum is found in pristine or secondary rainforests as well as in open wasteland, usually growing on sand or limestone; from 20 to 2,450 m elevation.

Common names and uses.

China. shan qie ( Zhang et al. 1994); Guangxi: tain tin ke tsz shue (Tsang 23902); Hainan: dithoulat (Lois, Lau 157), shan ke (Tsang 874). Indonesia. Java: tokokka, magay ( Blume 1826). Philippines: qumit (Ifugao, Conklin 217). Taiwan: mao zhu wan tao hua ('twigs are fluffy, many flowered, pink like peach flowers’)

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (2,387,194 km2, LC); AOO (160 km2, EN). Solanum pseudosaponaceum is widely distributed across tropical Asia, and where it occurs apparently grows in large populations at forest edges and other disturbed habitats.

Discussion.

This species was treated as S. macaoense Dunal in the "Flora of China" ( Zhang et al. 1994), however, the type specimen of S. macaoense (Callery 28/29, P00055495) is clearly conspecific with S. torvum , making S. pseudosaponaceum the oldest and correct name for this taxon. Solanum pseudosaponaceum is one of the few Torva clade species occurring outside of the Americas ( Aubriot et al. 2016a). It shares with the American members of the clade a shrubby habit, usually branched inflorescences, and hermaphroditic flowers. In common with S. poka , S. peikuoense and S. torvoideum , it has red berries; members of this clade native to the Americas have green to yellowish green mature fruits (e.g., S. chrysotrichum , S. torvum ). For characters useful in distinguishing S. pseudosaponaceum from other members of the Torvum clade see descriptions of S. poka and S. torvum .

The specimen (Martin 1383) treated as S. asperolanatum Ruiz & Pav. in Hul and Dy Phon (2014) is a juvenile plant of S. pseudosaponaceum ; in the absence of any inflorescences, it is difficult to place, but the pubescence and prickles accord better with it being identified as S. pseudosaponaceum than S. chrysotrichum (another determination on the sheet at P). Solanum pseudosaponaceum is only known from a few collections in Indochina. Solanum asperolanatum is an Andean endemic and does not occur in tropical Asia.

The disjunct distribution of the Torva clade is most likely due to long-distance dispersal ( Dupin et al. 2016; Echeverría-Londoño et al. 2020), but from a single event, all species included in phylogenetic analyses ( Aubriot et al. 2016a) are each other’s closest relatives.

The specimen in Nees van Esenbeck’s herbarium ( Stafleu and Cowan 1981) at GZU (GZU0005524455) is annotated "Blume leg." and has an original label with the common name “Tokkoka” cited in the protologue. We have selected this as the lectotype for S. pseudosaponaceum because it is clearly from Blume’s herbarium and has additional information from the protologue on it. The two collections in L here recognised as isolectotypes bear minimal labelling, and none of them has any locality or common name information; one of them (L0003669) has been previously annotated as “lectotype” by an unknown user or by L herbarium staff.

In the protologue of Solanum inaequilaterale ( Merrill 1906) two collections were cited, Merrill 4807 and Elmer 6204, the latter with the comment "appears to be a form of this species". We have selected the best preserved of the duplicates we have seen of Merrill 4807 (US [00027616, acc. # 710478]) as the lectotype for this name, as Merrill unequivocally accepted this collection as his new species.

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 57. Solanum pseudosaponaceum Blume A herbarium specimen collected in Taiwan in 1864 (Oldham 342, BM 000846375) B fertile stem (field photograph, unvouchered, Philippines) C open fruit with seeds inside (field photograph, unvouchered, Taiwan) D inflorescence (field photograph, unvouchered, Philippines) E infructescence (field photograph, unvouchered, Philippines). Photograph credits: A CC-BY, © copyright The Trustees of the Natural History Museum, London B, D, E D. Tandang C M. - I. Weng.

Figure 58. Distribution of S. pseudosaponaceum.