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Pollen morphology in Psychotria (Rubiaceae, Rubioideae, Psychotrieae) and its taxonomic significance. A preliminary survey
Author(s) -
Johansson Jan Thomas
Publication year - 1993
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/j.1756-1051.1993.tb00004.x
Subject(s) - pollen , biology , rubiaceae , reticulate , botany , psychotria , morphology (biology) , aperture (computer memory) , taxonomy (biology) , inflorescence , zoology , physics , acoustics
The pollen morphology in 168 species of Psychotria (Rubiaceae, Rubiodeae, Psychotrieae) has been investigated using light microscopy and, for 61 of the speices, scanning electron microscopy. Transmission electron microscopical studies have been carried out for seven of the species. Psychorria is very heterogeneoous pollen morphologically and pollen grain characteristics cannot be used for the delimination of the basis of aperture morphology, thickness of exine, size of lumina, muri, columellae and bacula, and sculpture. A key to the identificantion of the pollen types is presented and all types are issstrated. The pollen grains in Psychotria are usually 3–to 5colporte, 3‐to 5‐colpate or inapertuarate, rarely 2–4‐or 5‐porate, and have an exine that vanes widely in thickness. The sexine is reticulate, microreticulate, tectate‐perforate, rugulate or intectate, and smooth or sculptured. Exine morphology presents important characters for the taxonomic subdivision of Psychotria . Previous intrageneric classifications are in part supported by pollen morphology, but contradictions between this and other sets of charactes, such as inflorescence features. are common.