Solanum mite subsp. hexazygum Bitter:
Bolivia (South America)

Solanum semievectum Bitter:
Peru (South America)

Solanum quinquefoliolatum Bitter:
Brazil (South America)

Solanum mite Ruiz & Pav.:
Bolivia (South America)
Ecuador (South America)
Peru (South America)
Brazil (South America)

Solanum huallagense Bitter:
Peru (South America)

Solanum apiculatibaccatum Bitter:
Peru (South America)
Brazil (South America)

Throughout the Amazon basin from Colombia and the E slopes of the Andes in Peru and Bolivia to the mouth of the Amazon in Brazil, from nearly sea level to 1500 m.

Habit

Small single-stemmed shrub to 1 m tall, often growing in large colonies in open places. Stems ca. 1 cm in diameter, green, white-lenticellate, very woody at the base, when dry usually hollow, extremely variable in pubescence, from glabrous to densely pubescent with simple uniseriate trichomes 1-1.5 mm long, these drying white and cateniforme.

Sympodial Structure

Sympodial units unifoliate.

Leaves

Leaves pinnate, 10-50 x 7-25 cm, elliptic to obovate, with 2-5 pairs of leaflets, the leaflets not always perfectly opposite, the pubescent reflecting that of the entire plant, glabrous to densely pubescent both adaxially and abaxially with simple uniseriate trichomes on the veins and the lamina, the trichomes 1-2 mm long, white, leaves glabrescent with age, but not markedly so, leaves rarely purple abaxially; petiole 5-15 cm long; lateral leaflets elliptic to obovate, 7.5-15 x 2.3 cm, with ca. 12-14 pairs of primary veins, the base attenuate, markedly oblique and enlarged basiscopically, the apex acute to acuminate; petiolule 2-3 mm; basal leaflets usually somewhat smaller than the laterals, but similar in shape; terminal leaflet obovate, usually much wider than the laterals, 9-15 x 3.5-8(-10) cm, the base attenuate, usually winged and decurrent onto the rachis, the apex acute to acuminate; petiolule winged onto the rachis.

Inflorescences

Inflorescence axillary, 0.5-5 cm, 1-8 arising from an axil, occasionally once-branched, bearing 5-10 flowers at anthesis, with up to 100 scars, pubescence as the rest of the plant, glabrous to densely pubescent. Buds globose, ca. 2 x 2 mm, exserted from the calyx tube. Pedicels at anthesis 4-6 mm long, filiform nodding.

Flowers

Flowers with the calyx tube 1-1.5 mm, broadly conical, abruptly narrowing to the pedicel, the lobes 1-1.5 x ca. 1 mm, deltate, glabrous to sparsely pubescent with simple uniseriate trichomes abaxially; anthers 1-1.5 x 1-1.5 mm, poricidal at the tips, papillose abaxially, the free portion of the filaments 0.5-1 mm long, the filament tube 0.05 mm; ovary conical, glabrous; style 3-4 mm long, glabrous or minutely papillose in the lower half, some flowers short-styled and the style included in the anther cone; stigma capitate to slightly clavate.

Fruits

Fruit a globose, occasionally somewhat apically pointed, green berry, 0.8-1.2 cm in diameter, 1-1.2 cm long, the surface smooth; fruiting pedicel 0.8-1 cm long, nodding.

Seeds

Seeds 2.3-3.0 x 1.6-2.3 mm, ovoid-reniform, brown, 35-60 seeds per fruit; epidermal cells sinuous and irregular, with anticlinal thickenings but without projections.

Type collection for Solanum mite subsp. hexazygum Bitter
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): O. Buchtien
Year Collected: 1907
Locality: San Carlos, Mapiri., La Paz, Bolivia, South America
Elevation (m): 700 to 700

Type collection for Solanum mite subsp. hexazygum Bitter
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): O. Buchtien
Year Collected: 1909
Locality: San Carlos, Mapiri., La Paz, Bolivia, South America
Elevation (m): 700 to 700

Solanum mite is a member of the Solanum mite group of section Pteroidea in the Potato clade (Bohs, 2005). Based on morphology (Knapp & Helgason, 1997), S. mite is sister to S. chamaepolybotryon.

Solanum mite is the most common of the species of section Pteroidea, forming large thickets in treefall gaps in the primary and secondary forest and along streams and roads in partial shade. Like S. anceps, it is basically an Amazonian species, but unlike S. anceps, S. mite occurs only in the southern part of the Amazon basin, not extending far north of the N bank of the Rio Amazonas. Solanum mite is superficially similar to both S. conicum and S. uleanum, but can be differentiated easily from those species by its rounded fruit, pendant at maturity. Solanum mite can be hard to distinguish from S. conicum in flower, but the latter usually has larger flowers with the petals held planar at anthesis, while S. mite has tiny ones with strongly reflexed petals. Other differences from S. conicum are discussed with that species. Numbers of leaflets and size of leaves are extremely variable in S. mite, but leaflet shape is consistently obovate, with the terminal leaflet usually much larger and more enlarged in the distal third. The type specimen of S. pteleifolium (Martius s.n.) has ternate leaves with large, broad leaflets, There exist however a range of intermediates in both leaflet size and number: Maas et al P12838 from Acre, Brazil and Plowman et al. 6401 from near Leticia on the Colombia/Peru border approach Martius’s collection in their broader leaflets, but given the range of variability in S. mite, we prefer to take a broad concept of the species. Many of the minor variants have been described as separate species by Bitter (see synonymy), but the range of variation in S. mite as recognized here encompasses all of these.

Huge variability in leaf pubescence of collections made in the department of San Martín, Peru by Knapp in 1986, shows that pubescence density and occurrence are both quite variable within populations of S. mite. In this series of collections, made near Tarapoto, no differences in phenology or other ecological characteristics were observed, and no morphological differences other than pubescence were seen. The nature of inheritance of this character is not known, but is likely to be relatively simple.

In typifying synonyms of Solanum mite, we have selected specimens we have seen and have chosen those which are widely distributed. Bitter cited two herbaria in his original description of Solanum mite subsp. hexazygum, “herb. Buchtien” now housed at US, and “herb. Vratisl.” (either WRSL or BRA, either of which Bitter could have visited). We were not able to obtain a specimen from the latter, so have chosen to lectotypify this taxon with the US sheet. In describing S. huallagense, Bitter cited Spruce duplicates in K, BM and W. The sheet at K selected by Knapp & Helgason (1997) as the lectotype, is from the first set of Spruce’s duplicates and is annotated in Bitter’s hand. No lectotype has been selected nor neotype chosen for S. apiculatibaccatum as Bitter cited no herbarium in the original description and the only duplicate traced of Ule 9731 is a sheet at B [F neg. 2705], no longer extant.