ISSN:
1615-6110
Keywords:
Angiosperms
;
Caryophyllaceae
;
Silene latifolia
;
S. alba
;
S. pratensis
;
Geographic variation in pollen morphology
;
clinal variation
;
detrended correspondence analysis
;
character incongruence
;
pollen dimorphism
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Reticulate and microechinate pollen forms withinSilene latifolia (S. alba, S. pratensis) were first described from N. America, where the species is an introduced weed. A previous study showed that the two forms also exist in Europe and intergrade along a zone roughly congruent with intergradation zones in seed morphology and flavone glycosylation genotypes. The present survey of pollen from herbarium specimens is more extensive and covers localities from nearly the whole of the species' native Eurasian and North African range. The first axis of a detrended correspondence analysis (DCA) of qualitative characterstate data for 11 pollen morphological characters shows a gradient between the two extreme exine types, reticulate and microechinate. When mapped, the co-ordinates of pollen samples on this axis indicate a broad zone of intergradation which coincides approximately with the somewhat sharper transition between low- and high-tubercle seeds in C. and N. Europe, but becomes diffuse in Italy and the Mediterranean region and diverges from the seed transition zone in SW. Asia and the Middle East. The biological significance of the pollen morphs is unknown; the variation pattern in pollen morphology, unlike that in seeds, is not consistently correlated with macroclimate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00937197
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