Wood anatomy of Cussonia and Seemannaralia (Araliaceae) with systematic and ecological implications

Abstract

The wood structure of two related African genera, Cussonia Thunb. (15 of 21 species) and the monotypic Seemannaralia R.Vig. (Araliaceae) is examined. The considerable diversity in wood anatomical characters within these taxa is mostly related to environmental factors; taxonomic groupings or phylogenetic relationships seem to be less important. The shortening of vessel elements and fibres, an increase in vessel number per group, a decrease in vessel diameter and a reduction in the number of bars of perforation plates, are associated with the more temperat species. The changes in vessel grouping show a significant correlation with rainfall. The placement of the simple-leaved Cussonia species in the subgenus Protocussonia and the isolated position of C. paniculata Eckl. & Zeyh., the only member of the subgenus Paniculatae, are supported. Many Cussonia species share a very low fibre to vessel element length ratio. Despite the basal position of Seemannaralia relative to Cussonia revealed by molecular data (Plunkett et al. 2004), its wood structure is more specialised in terms of the Baileyan major trends in wood evolution. This discrepancy may be the effect of a long-term adaptation of tropical ancestors of Seemannaralia to drier biomes.

Systematic and ecological wood anatomy of NeotropicalSchefflera(Araliaceae), with an emphasis on theDidymopanaxgroup

“…and Seemannaralia R.Viq. (De Villiers et al, 2012) and in tree floras from humid environments in Brazil, when compared with those of semi-arid and arid habitats (Alves & Angyalossy-Alfonso, 2000). Thus, the loss of scalariform perforation plates could be considered an ecological trend rather than solely a latitudinal one.…”

A Review of Botany, Therapeutic Value, Phytochemistry, and Pharmacology of Cussonia Paniculata

“…The genus Cussonia Thunb. comprises about 22 species which are mainly trees or shrubs or occasionally subshrubs recorded in grasslands, woodlands, and forests of sub-Saharan Africa, the Arabian Peninsula (Yemen), and the Comoro Islands [40][41][42][43][44][45][46]. C. paniculata is widely used as a decorative and ornamental plant, as the species is frost-resistant and therefore recommended for rockeries, bonsai, and other gardens [42,[47][48][49][50][51][52][53][54][55].…”

Cussonia Spicata Thunb. In Tropical Africa: Phytochemistry, Pharmacology, and Medicinal Potential

“…The genus Cussonia Thunb. comprises about 22 species which are mainly trees or shrubs or occasionally subshrubs recorded in grasslands, woodlands, and forests of sub-Saharan Africa, the Arabian Peninsula (Yemen) and the Comoro Islands [20][21][22][23][24][25][26]. Cussonia spicata is widely used as herbal medicine in tropical Africa [27][28][29][30][31].…”