Solanum gonocladum Dunal, Prodr. [A. P. de Candolle] 13(1): 93. 1852.

Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), PhytoKeys 231, pp. 1-342 : 1

22. Solanum gonocladum Dunal, Prodr. [A. P. de Candolle] 13(1): 93. 1852.

Figs 68 , 69

Solanum poecilochromifolium Rusby, Bull. New York Bot. Gard. 4: 419. 1907. Type. Bolivia. sin loc., sin. dat., M. Bang 2515 (no herbaria cited; lectotype, designated here: NY [00172135]; isolectotypes: K [K000585519], NY [00172134], US [00027749, acc. # 1324710]).

Solanum bangii Bitter, Repert. Spec. Nov. Regni Veg. 10: 552. 1912. Type. Bolivia. La Paz: vic. La Paz, 10,000 ft., 1889, M. Bang 64 (lectotype, designated by Barboza et al. 2013, pg. 264: BM [BM000778230]; isolectotypes: BR [BR0000005538201, BR0000005538539], G [G00343455], NY [00172113], PH [00030385]).

Solanum atricoeruleum Bitter, Repert. Spec. Nov. Regni Veg. 10: 563. 1912.

Solanum atricoeruleum Type. Bolivia. La Paz: sin. loc., 3,800 m, Apr 1910, O. Buchtien 2964 (no herbaria cited; lectotype, designated here: US [01919650, acc. # 1133279]; isolectotypes: NY [00139058], US [01919649, acc. # 700119]).

Solanum nanum Bitter, Repert. Spec. Nov. Regni Veg. 10: 564. 1912. Type. Bolivia. La Paz: sin. loc., 3,800 m, Apr 1910, O. Buchtien 2963 (no herbaria cited; lectotype, designated here: US [00027700, acc. # 133298]; isolectotypes: GOET [GOET003481], US [00027465, acc. # 1133278; 01014276, acc. # 700118], NY [00172103]).

Type.

Bolivia. La Paz: circa Roma de la Paz, A. D’Orbigny 1541 (lectotype, designated here: P [P00335462]; isotypes: G [00359947], P [P00335463], W [acc. # 1889-0127571]) .

Description.

Small shrubs to 1 m high, often caespitose, the base markedly woody. Stems terete, with a very leafy appearance, moderately pubescent with white eglandular, simple few-celled uniseriate trichomes to 0.5 mm long, these usually strongly antrorse; new growth densely white pubescent with eglandular simple uniseriate trichomes like those of the stems; bark of older stems pale greenish or greyish brown. Sympodial units plurifoliate, the leaves not geminate, often clustered in groups of different sizes at the nodes giving the plant a very leafy appearance. Leaves simple, the blades 0.9-8 cm long, 0.3-3.2 cm wide, narrowly elliptic to elliptic, widest at or just above the middle, membranous to chartaceous, concolorous; adaxial surfaces sparsely to moderately and evenly (to very densely in extremely small-leaved plants) pubescent with white eglandular simple few-celled uniseriate trichomes to 0.5 mm long; abaxial surfaces similarly pubescent, but the trichomes denser along the veins; principal veins 4-5 pairs, more densely pubescent than the lamina abaxially; base attenuate, decurrent along the petiole but not along the stem; margins entire or very occasionally with a few scattered teeth to ca. 1 mm long, ca. 1 mm wide; apex acute to slightly obtuse, with the ultimate tip rounded; petioles absent and the leaves sessile from the attenuate bases, the winged portion to 1 cm long. Inflorescences opposite the leaves, forked (occasionally unbranched, e.g., Nee 34108), 2-6(-10) cm long, with 20-30 flowers borne in the distal half of the branches, evenly pubescent with antrorse white eglandular simple few-celled trichomes ca. 0.5 mm long like those of the stems; peduncle 1-3 cm long; pedicels 0.9-1.4 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, rather stout-looking, evenly pubescent like the rest of the inflorescence, spreading at anthesis, articulated at the base; pedicel scars evenly spaced 1-3 mm apart. Buds ellipsoid, the corolla ca. halfway exserted from the calyx before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 2-2.5 mm long, cup-shaped, the lobes 1.5-2 mm long, 1.2-1.5 mm wide, usually shorter than the tube, deltate to short-triangular with rounded tips, usually drying black, evenly pubescent with white eglandular simple few-celled uniseriate trichomes ca. 0.5 mm long, these usually somewhat antrorse, the sinuses thinner and in dry material appearing somewhat scarious. Corolla 1.3-2 cm in diameter, pale purple to violet with a yellow central star, stellate, lobed ca. halfway to the base, the lobes ca. 5 mm long, 3.5-6 mm wide, spreading at anthesis, adaxially glabrous, abaxially densely pubescent-puberulent where exposed in bud with eglandular simple uniseriate trichomes to 0.2 mm long or less, the interpetalar tissue glabrous. Stamens equal; filament tube minute; free portion of the filaments 1-1.5 mm long, with a few transparent tangled simple uniseriate trichomes at the base; anthers 4-4.5 mm long, 1.5-1.75 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 7-8 mm long, straight (curved in bud), long-exserted beyond the anther cone (sometimes exserted from the closed corolla in bud), densely pubescent in the lower half; stigma large capitate, the surfaces minutely papillate, green in live plants. Fruit a globose berry, 0.8-1 cm in diameter, greenish yellow when ripe, the pericarp thin, more or less shiny, translucent, glabrous; fruiting pedicels 1.4-1.5 cm long, ca. 0.7 mm in diameter, ca. 1.2 mm in diameter at the apex, somewhat woody, strongly deflexed at the base with a distinct kink at the very base so the fruits almost point back towards the main stem, not persistent; fruiting calyx not markedly accrescent, the tube 2-3 mm long, appressed on the berry, the lobes 2-2.5 mm long, spreading, with the tips reflexed and markedly rounded. Seeds 20-40 per berry, ca. 2 mm long, 1.2-1.5 mm long, flattened and teardrop shaped, reddish brown, the surfaces minutely pitted, the testal cells sinuate in outline. Stone cells 4-6 per berry, 2 apical ca. 1 mm in diameter, the rest (2-4) equatorial or scattered, ca. 0.7 mm in diameter, all cream-coloured. Chromosome number: not known.

Distribution

(Fig. 70 ). Solanum gonocladum is a high elevation Andean species, occurring from central and southern Peru (Depts. Ancash, Ayacucho, Cusco, Junín, Moquegua, Puno), Bolivia (Depts. Chuquisaca, Cochabamba, La Paz, Potosí) into northern Chile (Region XV [Arica y Parinacota]).

Ecology and habitat.

Solanum gonocladum is a plant of open spaces, often occurring in rocky landslides and outcrops; it is most commonly collected in puna or pre-puna habitats from (1,500) 2,600 to 4,000 m elevation.

Common names and uses.

Peru. Cusco: chinchi-chinchi (Herrera 2178); Moquegua: ñuccho hembra, ñuccho con pelo (Montesinos 920). No uses recorded.

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 541,223 km2 [LC]; AOO = 284 km2 [EN]. Solanum gonocladum occurs widely in the high Andes and is often a plant of open, disturbed areas. It has been recorded from protected areas in Bolivia (e.g., Parque Nacional Tunari).

Discussion.

Solanum gonocladum is an upright shrubby plant often with scrambling stems that are extremely woody at the base. The flowers are large in comparison to other South American morelloid species (to 2 cm in diameter, with anthers to 5 mm long) and the darkened spathulate calyx lobes that hug the base of the berry are diagnostic. It is usually a species of puna regions at high elevation, although Eyerdam 24741 (F, K) was collected at 1,500 m elevation. Solanum gonocladum is somewhat similar morphologically to S. interandinum , with which it shares spathulate calyx lobes and strongly deflexed fruiting pedicels but differs from it in its slightly larger flowers (1.6-2 cm in diameter versus 0.8-1.4 cm in diameter, with anthers 3-5 mm long versus 2.5-3 mm long), and larger berries (0.8-1 cm in diameter versus 0.6-0.8 cm in diameter). In both species the inflorescence often remains on older stems after flowers and fruits have fallen. In the consensus phylogeny of Särkinen et al. (2015b) S. gonocladum was part of a clade including S. pallidum and S. cochabambense (as. S. probolospermum ).

One collection from the Bolivian Department of Potosí (Wood 10648) is included here with some reservation. It is the only collection we have seen from this far south in Bolivia, and in the phylogenetic reconstructions of Särkinen et al. (2015b) it does not cluster with other accessions of S. gonocladum nor with S. salicifolium which it also somewhat resembles. Since the ploidy level of S. gonocladum remains untested and the accession could be clustering with one or the other parent if S. gonocladum is a polyploid, we hesitate to recognise this collection as a new taxon until further collecting in southern Bolivia reveals additional accessions.

In describing S. gonocladum , Dunal (1852) cited two specimens he had seen in Paris both collected by Alcide d’Orbigny ( d’Orbigny 1541 and 1536B); we have selected the more complete of these two gatherings at P ( d’Orbigny 1541, P003355462) that is annotated by Dunal and has the type locality on the original label as the lectotype for this name.

The protologue of S. poecilochromifolium does not cite a herbarium ( Rusby 1907); we have selected the best preserved of the duplicates of Bang 2515 at NY (barcode 00172135) with flowers and fruits as the lectotype.

Solanum bangii was lectotypified by Barboza et al. (2013) with the specimen of Bang 64 at BM (BM000778230). Other duplicates of Bang 64 were also used by Rusby (1895) to describe S. pallidum , so care must be taken in assigning lectotype status to duplicates of Bang 64 (see discussion in description of S. pallidum ).

Bitter (1912a) described both S. atricocoeruleum and S. nanum from collections made by Otto Buchtien in Bolivia but cited no specific herbaria. Both Buchtien 2964 and Buchtien 2963 pro parte were cited in the protologue of S. atricocoeruleum and only Buchtien 2963 pro parte was cited for S. nanum , differentiating the duplicate cited as being smaller. We have therefore selected Buchtien 2964 at US (barcode 01919650, acc. # 1133279) annotated by Bitter as S. atricocoeruleum as the lectotype for S. atricocoeruleum and Buchtien 2963 (US barcode 00027700, acc. # 133298, annotated as S. nanum by Bitter) as the lectotype of S. nanum . Other duplicates of Buchtien 2963 (e.g., GOET003481) were annotated by Bitter as S. atricocoeruleum . A number of collections with the collecting number Buchtien 2964 (e.g., B_10_0248774, HBG-511402, HBG-511403, HBG-511404) have collection dates in the 1930s, too late to be original material for S. atricoeruleum , despite bearing the same collection number.

Figures

Figure 68. Solanum gonocladum A habit with flowers and fruits B flowering habit with larger leaves C flowering habit with smaller leaves D woody base of stem with roots E detail of adaxial leaf surface F detail of abaxial leaf surface G detail of adaxial leaf surface (glabrous individual) H detail of abaxial leaf surface (glabrous individual) I bud J dissected flower K fully mature fruit with seed (A, E, F, K Buchtien 4454 B, I Buchtien 8665 C, D Buchtien 2964 G, H, J Buchtien 4452). Illustration by R. Wise.

Figure 69. Solanum gonocladum A habit B smaller habit C details of flowering and fruiting branches (A Buchtien 537 [E 00426360] B Buchtien 467 [E 00426359] C Balls 5892 [E 00426434]). Reproduced with permission of the Trustees of the Royal Botanic Garden Edinburgh.

Figure 70. Distribution map of Solanum gonocladum.