Notes on the genus <i>Cussonia</i> in South Africa

Abstract

Information gathered during studies of the genus Cussonia under field conditions is presented. The development of the inflorescences, and branch and leaf initiation, is given special attention. The subdivision of the genus Cussonia is discussed and the following new subgeneric taxa are created: Subgenus Cussonia (type species: C. spicata Thunb.) with two sections: Sect. Cussonia and Sect. Capitata Strey; Subgenus Paniculata Strey (type species: C. paniculata Eckl. Zeyh.); Subgenus Protocussonia (type species: C. natalensis Sond.). It is pointed out that the names C. kraussii Hochst. and C. chartacea Schinz have been misapplied to two undescribed species, and are synonyms of C. spicata Thunb. and Schefflera umbellifera (Sond.) Baill., respectively. Four new species are described viz. C. arenicola Strey, C. zuluensis Strey, C. nicholsonii Strey and C. sphaerocephala Strey.

The taxonomic significance of leaf anatomical characters in Cussonia and related genera (Araliaceae)

“…Simple uni‐digitate leaves, once‐compound umbels, well developed internodes, spherical fruits and short flowers characterise subgenus Protocussonia . This differs from Strey's (1973, 1981) diagnoses: subgenus Protocussonia with palmately compound leaves; subgenus Paniculata with paniculate spikes and palmate leaves; subgenus Cussonia with palmate to bi‐digitate leaves. These two systems were unfortunately based only on the southern African members of the genus.…”

“…The flowers are sessile or shortly stalked and subtended by one to three bracts. The fruits are fleshy and almost round or subglobose (Cannon, 1970, 1978; Strey, 1973, 1981; Bamps, 1974a,b; Reyneke, 1981, 1982). Previous studies of Cussonia (Harms, 1914; Strey, 1973, 1981; Bamps, 1974a,b; Reyneke, 1981, 1982) have shown it to be taxonomically complex and morphological characters to be variable and often confusing when used to distinguish species.…”

“…Baill. were formerly included in Cussonia (Viguier, 1906; Harms, 1914; Strey, 1973, 1981; Burtt & Dickison, 1975; Reyneke, 1981; Plunkett, Wen & Lowry, 2004). As these taxa display morphological similarities to Cussonia , such as leaves borne on the end of branches, a reduction in leaf complexity in the developing inflorescence and an inflorescence carried on terminal branches or stems, it seems clear that a leaf anatomical study should include members of these two genera.…”

“…(now Schefflera umbellifera ) were included in Neocussonia . Strey (1973) divided the genus into three subgenera, namely Cussonia , Paniculata Strey and Protocussonia Strey, based on leaf and inflorescence morphology. Subgenus Protocussonia is circumscribed as having simple, palmately lobed leaves, a panicle of umbels, compressed unilocular fruits and an absence of bracts.…”

“…Section Capitata Strey (of subgenus Cussonia ) has single umbels, racemes or spikes, whereas section Cussonia has once‐compound umbels of spikes. Reyneke (1981, 1982) proposed some changes to Strey's (1973) system, including elevation of section Capitata Strey to a subgenus and the creation of two sections within subgenus Capitata (Strey) Reyneke, namely Sessiliflora Reyneke and Pedicellata Reyneke. Reyneke (1981, 1982) placed more emphasis on the inflorescence morphology.…”