Solanum sessile Ruiz & Pav.

  • Authority

    Knapp, Sandra D. 2002. section (Solanaceae). Fl. Neotrop. Monogr. 84: 1-404. (Published by NYBG Press)

  • Family

    Solanaceae

  • Scientific Name

    Solanum sessile Ruiz & Pav.

  • Type

    Type. Peru. Huánuco: Muña, Ruiz & Pavón s.n. (lectotype, MA, designated by Knapp, 1991a; isolectotypes, MA, frag. MPU).

  • Synonyms

    Solanum pulchrum Dunal, Solanum pulchrum var. peruvianum Dunal, Solanum dibrachiatum Van Heurck & Müll.Arg., Solanum marmellosanum Bitter, Pheliandra herthae Werderm., Solanum grandifolium C.V.Morton

  • Description

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    Species Description - Shrubs to small trees, 2-8 m tall; young stems and leaves glabrous to minutely puberulent with erect uniseriate trichomes ca. 0.1 mm long, these golden in dry specimens; older stems glabrate, occasionally with some scattered uniseriate trichomes; bark of older stems reddish-brown, later grayish. Sympodial units usually difoliate, geminate. Leaves very large, obovate, widest distal to the middle, usually in the distal third, glabrous above, occasionally with minute uniseriate trichomes along the veins beneath, this condition extremely variable; major leaves 15-40 x 9-20 cm, with 9-11 pairs of main lateral veins, these raised above, prominent and golden beneath, the apex acute, the base variable, from sessile and slightly cordate to acute; petioles 0-1 cm long, often broadly winged with the decurrent leaf base; minor leaves differing from the major ones in shape and size, orbicular to obovate, 2.5-13 x l .5-9 cm, the apex acute, the base rounded to acute; petioles ca. 5 mm long. Inflorescences terminal and overtopping the leaves at the shoot tips, later lateral and opposite the leaves, complex and many-times furcate, 6-25 cm long, 20-100-flowered, sparsely to densely puberulent with erect uniseriate trichomes like those of the young stems and leaves, the trichomes 0.1-0.3 mm long, golden in dry specimens; pedicel scars irregularly spaced 1-5 mm apart, corky and slightly raised from the inflorescence axis. Buds globose and completely enclosed in the calyx when quite young, later the corolla exserted and the buds long-ellipsoid, the corolla ca. 2 times longer than the calyx tube. Pedicels at anthesis deflexed, white and fleshy, 0.6-1.1 cm long, tapering from the abrupt narrowing below the calyx tube to a slender base ca. 0.5 mm diam. Flowers with the calyx tube thick and woody, fleshy, white or greenish-white in live plants, broadly cup-shaped, 2.5-3.5 mm long, the lobes broadly deltoid, occasionally apiculate, the margins thickened and whitish in dry material, glabrous or minutely puberulent with erect uniseriate trichomes ca. 0.1 mm long; corolla white and fleshy, 1.5-2.5 cm diam., lobed 2/3 of the way to the base, the lobes planar at anthesis, the tips and margins of the lobes densely papillose with occasional uniseriate trichomes; anthers 3.5-4 x 1-1.5 mm, the tenninal 0.5 mm thickened and paler, poricidal at the tips, the pores teardrop shaped; free portion of the filaments 0-0.5 mm long, the filament tube 0.5-1 mm long; ovary glabrous or pubescent with minute, golden, uniseriate trichomes ca. 0.1 mm long; style in long-styled flowers 0.8-1 cm long, in short-styled flowers ca. 1 mm long, straight; stigma capitate, minutely papillose. Fruit a globose, green berry, 1-1.5 cm diam., in dry specimens woody and hard; fruiting pedicels erect and woody, 1-1.7 cm long, occasionally deflexed due to the weight of the fruits and the size of the inflorescence, 1.5-2 mm diam. at the base, thicker at the apex, ca. 3 mm diam.; calyx lobes slightly accrescent and woody in fruit. Seeds pale tan, ovoid-reniform, 2.5-4 x 2-3 mm, the surfaces minutely pitted. Chromosome number: n = 12 (vouchers Knapp & Mallet 6207, 6316, 6391, 6569).

  • Discussion

    With the exception of Solarium oppositifolium, S. sessile is the most widespread and variable of the species of this group. It is most closely related to S. obovalifolium (Cordillera de la Costa, Venezuela) and S. monadelphum (E Andean slope, Peru). Solanum sessile differs from the former in its much more complexly branched inflorescences, larger, fleshier flowers, and large, obovate, usually sessile leaves. It differs from S. monadelphum in its larger leaves, inflorescences, and flowers. Solanum sessile rarely grows in the riverbed habitat of S. monadelphum. In the forests of Quincemil (Dept. Cuzco, Peru), intermediates between S. sessile and S. monadelphum occur (see discussion of S. monadelphum). The most distinctive features of S. sessile are its large, branched inflorescences, and large, fleshy flowers.

    Solanum sessile is a widespread species, with several well-marked geographical races. These are briefly described here.

    1) Populations from near Muña, in middle-elevation central Pem, have strongly sessile leaves, congested inflorescences with little or no axis between the flowers, and very large, fleshy flowers. Ruiz and Pavón’s collection of Solanum sessile is from this area, an isolated Andean valley in the department of Huánuco.

    2) In areas of central Pem (not including the above area

    near Muña), plants are quite similar in appearance to the preceeding form, but the inflorescences are open and many-times branched, with somewhat smaller flowers. Most collections from middle-to high-elevation Pem are of this form.

    3) More northern, lower-elevation populations in Peru, Ecuador, Colombia, and Venezuela consist of plants with sessile leaves, the two leaves of the geminate pair markedly differing from one another, elongate, branched inflorescences, and pubescent berries. These populations have been called Pheliandra herthae and Solanum grandifolium. 4) Low-elevation Brazilian populations with open branched inflorescences and glabrous berries are of two types: a) those with sessile leaves have been called Solanum marmellosanum; and b) those with petiolate leaves have been called

    S. pulchrum.

    5) Plants from southeastern Pem and adjacent Brazil are almost completely glabrous, have sessile, geminate leaves, and glabrous berries. These populations grade into and are perhaps hybridizing with Solanum monadelphum.

    6) Plants from high-elevation Venezuela have coriaceous, sessile leaves that are often somewhat auriculate, and large open inflorescences.

    Many other forms of even more local occurrenc e could be described. To give formal names to the elements of this complex mosaic of variation would be co unterproductive, and would only serve to confuse an already confusing situation. The above well-marked forms grade into one another, and the collection sample is quite small for this forest species. Although perhaps difficult for the field botanist, it is more realistic phylogenetically to leave this complex pattern under the name of Solanum sessile until detailed work is done on the complex.

    Individuals of Solanum sessile are most likely andromonoecious, as they bear both long- and short-styled flowers. Few berries are set on any given inflorescence, lending support to this hypothesis. The sym-podial structure of S. sessile is quite variable (see above and description). Some plants have difoliate, geminate sympodia, while others appear to have plurifoliate sympodia (for discussion of sympodial types, see Morphology). This difference largely depends on the part of the plant taken to make the specimen in question. If only the most recent inflorescence is taken, the sympodia appear plurifoliate, and the inflorescence terminal, with no shoot growth continuing. On the other hand, if a lower node is taken, the inflorescence appears to be opposite the leaf, and the sympodium difoliate and geminate. Solanum sessile is a good example of the difficulties involved in using inflorescence position to identify species in sect. Geminata. This single species has been placed in two subgenera due to this variability.

  • Common Names

    maikuanim, mun sauk, sacha congompe, sanango

  • Distribution

    On the eastern slope of the Andes from Colombia to Bolivia, extending into Amazonian Brazil. A species of wide altitudinal range, from 100 m in the Amazon basin to 1800 m on the slopes of the Andes in central Peru and Venezuela.

    Venezuela South America| Barinas Venezuela South America| Mérida Venezuela South America| Colombia South America| Caquetá Colombia South America| Putumayo Colombia South America| Ecuador South America| Napo Ecuador South America| Pastaza Ecuador South America| Zamora-Chinchipe Ecuador South America| Peru South America| Amazonas Peru South America| Ayacucho Peru South America| Cusco Peru South America| Huánuco Peru South America| Junín Peru South America| Loreto Peru South America| Pasco Peru South America| San Martín Peru South America| Ucayali Peru South America| Bolivia South America| Cochabamba Bolivia South America| La Paz Bolivia South America| Pando Bolivia South America| Santa Cruz Bolivia South America| Brazil South America| Acre Brazil South America| Amazonas Brazil South America|