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Pollen morphology of the Cordioideae (Boraginaceae): Auxemma, Cordia, and Patagonula

1990; Springer Vienna; Linguagem: Inglês

10.1007/978-3-7091-9079-1_9

0172-6668

Joan W. Nowicke, James S. Miller,

Plant and Fungal Species Descriptions

The subfam. Cordioideae comprises three genera: Auxemma (2 spp.), Cordia (c. 300 spp.), and Patagonula (2 spp.). Pollen of 47 species was examined in LM and SEM, and a selected group in TEM. Auxemma and Patagonula are 3-colporate and variously rugulose or irregularly striate. In Cordia 43 species were examined, including both forms of seven heterostyled ones. Six pollen types were found: sect. Cordia is 3-colpor(oid)ate with a striate-reticulate tectum; sect. Varronia is 3-porate reticulate; sects. Gerascanthus, Myxa, Rhabdocalyx, and Superbiflorae are 3-colpor(oid)ate and variously spinulose; C. aurantiaca and C. taguahyensis are 3-colpor(oid)ate and clavate; C. lauta is 3-porate and conspicuously clavate; and C. bordasii is 3-colporate and “rugulose”. In TEM most cordias have a disrupted foot layer/endexine interface. Pollen from the long and short styled plants is only weakly dimorphic in SEM and TEM. Most Cordioideae can be distinguished from most Ehretioideae by the pseudocolpi or pseudocolpoid depressions and rugulose tecta in the latter subfamily. The problems of measuring pollen grains are also discussed.