(1215) Proposal to conserve the name Cinchona dichotoma Ruiz & Pav. (Rubiaceae) with a conserved type

Abstract

Joosia is a genus of 11 species extending from Panama along Andes to northernmost Bolivia. Most of its species are rare or, at least, have very restricted ranges. The only widespread species, and only that is reasonably well represented in herbaria, is J. umbellifera H. Karst. (Fl. Columb. 1: 9. 1859), which occurs throughout range of genus. Karsten originally differentiated Joosia umbellifera from J. dichotoma (Ruiz & Pav.) H. Karst. (Fl. Columb. 1: 9. 1859) by occurrence in J. umbellifera of terminally clustered inflorescence branches and by features of leaf indumentum and stipule size. A similar conception of J. dichotoma as differentiated by relatively minor characters was held by Standley (in Publ. Field Mus. Nat. Hist., Bot. Ser., 13(6): 33. 1936). Steyermark (in Brittonia 27: 260-262. 1975) discussed interpretation of Cinchona dichotoma on basis of a then recent, nearly topotypical collection (Schunke 1100) that he assumed to be conspecific with original collection of C. dichotoma. The Schunke collection differs strikingly from Joosia umbellifera in having a large, spathaceous calyx. The original description of C. dichotoma did not mention calyx or other floral details, but accompanying plate (Ruiz & Pav6n, Fl. Peruv. 2: t. 197. 1799) depicts a small, five-lobed calyx with triangular, acute lobes, such as that of J. umbellifera. The original collection, although represented by ample material, does not clarify this point, having only mature and nearly mature fruits with badly withered calyces. Steyermark's identification seems to have been based on implicit assumption that only one species exists in Huanuco, and he concluded that the artist responsible for plate 197 ... interpreted broken remains of basal portion of calyx tube as calyx teeth. However, one of details of plate 197 (fig. 1) was not drawn from a mature fruit but from an ovary from which corolla had just been shed, and on which calyx should thus be reasonably well preserved. This figure, too, shows a small, lobed calyx. Steyermark cited no characters of original collection that would support his identification of Schunke collection with C. dichotoma.