Monographs Details: Strychnos nigricans
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 nigricans
Description:Distribution and Ecology - Mexico: Jalisco: Mc Vaugh 20978 (fruits) (Mich); Tabasco (mun. Macus-pana), Gilly & Hernandez 384 (fruits) (Mich). British Honduras: Peck 832 (GH). Guatemala: Alta Verapaz, Krukoff s.n. (Apr. 1963) (fruits), Steyermark 44933 (US). Nicaragua: Zelaya (near El Recreo), Standley 19416 (F), 19788 (F). Brazil: Para: planalto between Xingu and Tapajos, Froes 32488 (fruits). Minas Gerais (Viçosa), J. C. Kuhlman 2515 (US). São Paulo (native to Jard. Bot.), Moyses Kuhlmann 2728 (US). Rio de Janeiro (Serra Tingua), Schott 5486 (W) (type coll.)Distribution: As I presently interpret this species, it has been collected in Mexico (Jalisco, Vera Cruz and Tabasco) ; British Honduras (where it is common) ; Guatemala (Izabal, Huehuetenango and Alta Verapaz) ; Nicaragua (Zelava) , and Panama (Canal Zone).

Discussion:Strychnos brachistantha Standley, Field Mus. Publ. Bot. 12: 412. 1936. Local name: “Ichbolay” (Alta Verapaz, Guatemala). The type collection of S. nigricans is from Serra Tingua, Rio de Janeiro, Brazil and it was not seen by us in 1942. We have accepted Sandwith’s and Ducke’s interpretation of this species (1: 316). The type collection is in flower. The type collection of S. brachistantha (Schipp S-899 from Temash River, British Honduras) is also a flowering specimen. In our monograph we placed S. mattogrossensis and S. mattogrossensis var. sarmentosa (type coll, of these two are from Matto Grosso, Brazil) under S. nigricans. We described the differences between S. nigricans and S. brachistantha (pubescence of inflorescences and leaf-blades) in our key (1: 306) and under S. nigricans (1: 315), and we stated under S. brachistantha: “this species is so similar to S. nigricans that its specific rank should be held under suspicion until further studies are made in the geographical distribution of both entities, especially in the critical zone of south-eastern Colombia.” In our monograph and all subsequent papers, veiy little attention was paid by us to the fruit characters and we so stated in 1942 (1: 258). Our keys were based exclusively on flower and vegetative characters. Ducke is quite correct in criticizing us on this point and he is also quite correct in pointing out the reasons why we were neglecting fruit characters (31: 12), one being that fully mature fruits were very poorly represented in the herbaria, and another reason being that my important Strychnos collection from the basin of the upper Rio Solimoes was made in the dry season at which time only a few immature fruits were available. From 1942 to 1955, mature fruits of many species were newly collected and at the time when Ducke was working on his paper on Strychnos (31), mature fruits of 45 Brazilian species were available to him for studies. It became apparent that in nigricans-brachistantha complex there is an entity with large fruits and thick shells and also an entity with small fruits and thin shells and they are excellently illustrated in Ducke’s paper (31). Ducke tentatively applied the name of S. brachistantha to the entity with large fruits and thick shells and S. nigricans to the entity with small fruits and thin shells and he left it to “bureau-botanists” to be concerned with the nomenclature, adding that a “field-botanist” studies plants and not names (31: 47). The name of S. nigncans cannot be applied to the small fruited entity with thin shells as the type coll, of it (in flower) is from the State of Rio de Janeiro where up to date no small fruited entity has been collected. It is necessary therefore to reinstate S. mattogrossensis as a valid species and interpret it as a small fruited entity with thin shells. The type collection of S. mattogrossensis (Moore 6725) is in flower but the type collection of S. mattogrossensis var. sarmentosa is in fruit. They are from the same locality and I interpret S. mattogrossensis as of the same entity as S. mattogrossensis var. sarmentosa. Presently I have no alternative but to reduce S. brachistantha (with reluctance) to the synonymy of S. nigricans. Originally I thought that their ranges are widely separated, but a recent collection (Froes 32488 with large fruits and thick shells) from the State of Para (planalto between Rio Xingu and Rio Tapajos) Brazil exploded this criterion. In their flower and vegetative characters they are very close, and we have separated them in our key on rather weak characters (1: 306). I have not seen a single collection of S. nigricans from Southern Brazil in fruit, but fruits were well illustrated by Ducke. They were drawn from J. G. Kuhlmann 1584, collected near Viçosa, Minas Gerais, Brazil. It is not clear however as to why this specimen is not cited by Ducke elsewhere in his paper (31: 45). It is quite likely that once this complex with large fruits and thick shells presently treated as S. nigricans is well studied in the field as well as on the basis of cultivated plants grown from seeds collected in Central America, and as well as from the Amazon basin and from Southern Brazil, two or more entities will be recognized. Of 22 specimens from Mexico and Central America, which were available to me to date, only five are in fruit (Gentle 3181 and Lundell 6266 from British Honduras and three recent collections cited in this paper). Only one collection in fruit (Froes 32488) is available from the Amazon basin. According to Ducke (31:45) four collections of this species in fruit from Southern Brazil were seen by him and they are as follows: Brazil, Minas Gerais (Viçosa), J. G. Kuhlmann s.n. (Herb. Viçosa 1515 and Jard. Bot. Rio 45535). Rio de Janeiro (Itatiaia, alt. 800 m, Parque National), Brade 17544 (with immature fruits). São Paulo: Moyses Kuhlmann 2608 (near São Paulo, forest reserve of Inst, de Bot.) ; Hoehne s.n. (Inst, dc Bot. 12894) (Cabreuva). Thirteen specimens sterile or in flower from Minas Gerais, Rio de Janeiro and São Paulo, were seen by me. Therefore they are from the same States as the specimens in fruit seen by Ducke. For information on the position of this species in Ducke’s key made on the basis of fruit characters, see (33: 85, 86, under S. brachistantha). The largest fruit of this species seen by me from a collection from Guatemala measures 5.0 cm in diam. with a shell 5.1 mm thick.
Distribution:Mexico North America| Honduras Central America| Guatemala Central America| Nicaragua Central America| Panama Central America|