Nectar sugar composition in the subfamily Alooideae (Asphodelaceae)

HPLC analyses of nectar samples from 82 species of the genera Aloe, Astroloba, Chortolirion, Gasteria, Haworthia, Kniphofia, Lomatophyllum and Poellnitzia have shown that the sugar composition of nectar is remarkably invariable within each of the genera. In the Alooideae, distinct suprageneric groups can be distinguished, based only on the relative proportions of sucrose, glucose and fructose. Three nectar types are present in the subfamily: (1) an alooid type (in Aloe, Kniphofia, Lomatophyllum and Poellnitzia) with less than 5% sucrose and equal proportions of glucose and fructose; (2) a gasterioid type (in Gasteria only) with sucrose dominant and equal proportions of glucose and fructose; (3) a haworthioid type (in Astroloba, Chortolirion and Haworthia) with sucrose dominant but with much more glucose than fructose.