Monographs Details: Cassia spruceana Benth.
Authority: Irwin, Howard S. 1966. Contributions to the botany of Guiana. IV. Legumonosae Caesalpinioideae. Mem. New York Bot. Gard. 15: 112-128.
Family:Caesalpiniaceae
Scientific Name:Cassia spruceana Benth.
Discussion:

C. sagotiana Benth. in Martius, Fl. Bras. 15 (2) : 93. 1870.

In commenting on some trees seen in Obidos, Para, Ducke (1922)5 suggests that C. sagotiana might be reinterpreted as a “geographical variety” of C. spruceana. Bentham (1871)6 had distinguished the two species, then known only by the respective types, by the former having more obtuse and coriaceous leaflets, less veined above and usually whitish beneath; the flower smaller, the intermediate anthers with longer basal lobes, etc.

All specimens available, including isotypes, have been examined, with special reference to Bentham’s characters. A summary of observations is presented in Table 1.

The two further characters used by Bentham, leaflet thickness and color contrast on the different blade surfaces, were noted by inspection as varying greatly in the materials under consideration. Because expression of the former character is governed at least in part by ontogenetic changes and because the latter cannot be judged with satisfaction from exsiccatae, no mensural values were determined.

The measurements given in Table 1 indicate that while the type specimens of C. spruceana and C. sagotiana differ in small degree, subsequent collections, admittedly few, from intervening and adjacent areas tend to reduce the validity of these characteristics as taxonomic criteria. C. spruceana, in the sense adopted here, is a widespread species showing not unexpected variability, none of it thus far suggesting the geographical correlation which might be used as the basis for infraspecific categories as suggested by Ducke.

The cited specimen is a first report for Amapa.