Monographs Details: Strychnos froesii Ducke
Authority: Krukoff, Boris A. 1965. Supplementary notes on the American species of Strychnos VII. Mem. New York Bot. Gard. 12: 1-94.
Scientific Name:Strychnos froesii Ducke
Description:Distribution and Ecology - Distribution: Known from the basins of the lower Rio Tapajos and of the lower Rio Xingu in the State of Para, also from the basin of the lower Rio Negro (near Manaos), in the State of Amazonas, Brazil.Brazil: Para: basin of the lower Rio Tapajos (planalto de Santarem), Froes 31016, 31328; basin of the lower Rio Xingu, Froes 32169 (Rio Jaracu, munic. Porto de Moz), 32154 (lagoa de Macapichi, Porto de Moz), 32395 (en frente Souzel), Amazonas: basin of the lower Rio Negro (on Rio Taruma, near Manaos), Ducke s.n. (August 8, 1941), 2272 (June 1, 1950; from the same plant as the type collection), Froes 24919 (US, type coll.), Ducke 2320 (K).This is a giant bush-rope provided with tendrils which abounds in high forest on terra-firme. Fruits near Manaos were collected in June, flowers in the basin of Rio Xingu in November. Fruits and seeds of this species were described by Ducke (31: 36). For information on its position in Ducke’s key made on the basis of fruit characters see (33: 86).

Discussion:There is not the slighest doubt that S. javariensis, S. diaboli and S. Froesii are distinct species. S. javariensis can be immediately distinguished from the two others on the striking vegetative characters (leaves resemble somewhat those of S. Castelnaeana of Breviflorae), whereas, S. Froesii can be immediately distinguished from the two others on the basis of its inflorescences. Its inflorescences are axillary, not terminal as in S. javariensis and S. diaboli. Nevertheless, the recently described S. Froesii caused considerable difficulties to Ducke and ourselves. This species was originally described on the basis of a fruiting specimen and wrongly placed in Intermediae, next to S. hirsuta which it does not resemble either in flower, fruit or vegetative characters. Its flowers were described by Ducke eight years later on the basis of Froes 32395 who finally placed it correctly with Longiflorae (33: 78). The first collection of this species (leaves of a young plant) made by Ducke on August 8, 1941, was sent to us for identification and we cited this through error under S. javariensis (2: 22) which it resembles in vegetative character of young plants only. Type Locality: Amazonas (basin of Rio Negro, on Rio Taruma, near Manaos), Brazil. This species was studied by Marini-Bettolo, Bovet and their coworkers. For the alkaloid content, toxicity, and curare action of the total extract, see (94: 856; 95: 1142, 1144). For rather extensive studies of the alkaloids of this species, see (96). In the summary the authors state that on extracting the plant a mixture of different alkaloids was obtained and 14 alkaloids were recognized by the use of chromatographic methods. The alkaloids which were characterized are as follows: “Alkadoids E, I, J, K (= C-dihydrotoxiferine), Toxiferine (C-toxiferine I), Fluorocurinine, Mavacurine” (108: 269). The above referred to work was done on stem bark collected by Ducke, one collection on Rio Taruma, near Manaos, Amazonas, Brazil in May 1953 and another collection also near Manaos in February 1952 (95: 1145; 108: 269).
Distribution:Brazil South America|