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A survey of leaf flavonoids in the portulacaceae

1986; Elsevier BV; Volume: 14; Issue: 6 Linguagem: Inglês

10.1016/0305-1978(86)90044-x

1873-2925

B. L. Nyananyo,

Plant and Fungal Species Descriptions

A survey of 26 species in 12 genera of the Portulacaceae showed the presence of flavonoids in 24, and their absence in two, Hectorella caespitosa Hooker fil. and Lyallia kerguelensis Hooker fil. Of the 24 positive species, 16 are reported for the first time. In all 24 however, flavonols and flavones did not occur together suggesting that this dichotomy might be useful for classification at and below the generic level in the Portulacaceae, e.g. the genera Silvaea Philippi (syn. Philippiamara Kuntze), Ceraria Pearson & Stephens and Portulacaria Jacquin which were previously grouped together on palynological characteristics have now been shown to differ in their leaf flavonoids, subsidiary cells of the stomata and geographical location: Silvaea possesses flavones and is endemic to South America, while Ceraria and Portulacaria possess flavonols and are endemic to Africa. The dichotomy also occurs below the generic level. In Calandrinia H.B.K. and Portulaca L. the dichotomy amongst their species is supported by other new taxonomic characters from cytology, palynology, pubescence of surfaces, type of subsidiary cells surrounding the leaf stomata and seed morphology recently elucidated by the author.