Monographs Details: Solanum leptorhachis Bitter
Authority: Knapp, Sandra D. 2002. section (Solanaceae). Fl. Neotrop. Monogr. 84: 1-404. (Published by NYBG Press)
Family:Solanaceae
Synonyms:Solanum macrotonum Bitter
Description:Species Description - Slender shrubs with arching, planar branches, 1-2 m tall, young stems zigzag, glabrous or puberulent with minute uni- or bicellular golden trichomes ca. 0.01 mm long; older stems glabrate, greenish-yellow. Sympodial units unifoliate, not geminate except on the basal, non-reproductive nodes. Leaves elliptic, widest at the middle, glabrous and matte above, glabrous or minutely hispidulous on the veins beneath, the blades 9-15(26) x 4-6(14) cm, with 8-10 pairs of main lateral veins, these parallel to one another and at right angles to the midrib, the apex acuminate, the base obtuse, then sharply attenuate, decurrent on the petiole and stem; petioles 0.5- 1.7 cm long, slightly winged from the decurrent leaf bases. Inflorescences opposite the leaves, long and slender, filiform, 1-8 cm long, bearing 1-2 flowers at a time, but with up to 25 pedicel scars, glabrous or minutely puberulent with trichomes like those of the young stems; pedicel scars widely and unevenly spaced, 3-7 mm apart. Buds globose, glabrous or minutely puberulent, greenish-white, becoming obovoid just before anthesis. Pedicels at anthesis threadlike and hanging, 1.5-2 cm long, tapering from the calyx tube to a filiform base ca. 0.2 mm diam. Flowers with the calyx tube broadly conical, ca. 1 mm long, glabrous or minutely puberulent, lobes rounded, 0.5-1 mm long, papillose at the tips; corolla pale greenish-white, translucent, 5-8(11) mm diam., lobed ca. 2/3 of the way to the base, the lobes planar or slightly reflexed at anthesis, papillose at the tips; anthers ca. 2.5 x 1 mm, poricidal at the tips, the pores teardrop shaped; free portion of the filaments less than 0.5 mm, the filament tube ca. 0.5 mm long; ovary glabrous; style 3-4 mm long, straight; stigma bright green in live specimens, small-capitate, minutely papillose. Fruit a globose berry, 0.8-1 cm diam., greenish-yellow when ripe; fruiting pedicel greatly elongated and hanging, 3.5-4 cm long, tapering from a basal diam. of ca. 0.5 mm to an expanded apex 3-4 mm diam. (this much more apparent on live specimens). Seeds pale tan, ovoid-reniform, ca. 3 x 2 mm, the surfaces minutely pitted, the margins somewhat incrassate. Chromosome number: n = 12 (voucher Knapp & Mallet 6160).

Discussion:Solarium leptorhachis is most closely related to S. tenuiflagellatum of montane coastal Venezuela, sharing with that species extremely long inflorescences, flowers with the corolla lobes planar or only slightly reflexed at anthesis, and fruiting pedicels three to four times their length at anthesis and greatly expanded and corky at the apex. Plants collected at higher elevations (Boeke & Loyola 2179, Luteyn & Lebrón-Luteyn 6490, Zak 1113, 1283, 1285) have larger, apparently thicker leaves and larger flowers than more typical plants. This species is a relatively common component of the understory, often growing in old light gaps and along small streams under closed canopy.

In Tinalandia, near Santo Domingo, Ecuador, the leaves of Solarium leptorhachis are fed upon by the larvae of the ithomiine butterfly Pteronymia glauca (see Table XI), and the plants are often severely defoliated by these caterpillars.

The specimen collected in Tumbes, Peru (Simpson & Schunke V 429), consists of a few apparently virally infected sucker shoots with very small, deformed leaves and very short inflorescences.
Distribution:Colombia South America| Nariño Colombia South America| Valle del Cauca Colombia South America| Ecuador South America| Azuay Ecuador South America| Carchi Ecuador South America| Cotopaxi Ecuador South America| Esmeraldas Ecuador South America| Guayas Ecuador South America| Imbabura Ecuador South America| Los Ríos Ecuador South America| Pichincha Ecuador South America| Peru South America| Tumbes Peru South America|