Authors: IlChan Oh AL Anderberg J Schönenberger A A Anderberg
Publish Date: 2008/02/12
Volume: 271, Issue: 3-4, Pages: 177-197
Abstract
We investigated seed morphology in 34 species of the genus Lysimachia and in 14 species and two subspecies of six additional genera Anagallis Ardisiandra Asterolinon Glaux Pelletiera Trientalis which have been shown to be closely related to or are placed within Lysimachia in previous molecular studies We studied seed shape seed coat structure and seed coat surface patterns Three major types of seed shape were identified 1 sectoroid 2 polyhedral and 3 coarsely rugose with concave hilar area In addition seeds may be keeled or winged The outer layer of the seed coat is either spongelike and adhering only loosely to the inner seed coat or it is thin and tightly adhering to the underlying tissue Seed surface patterns can be divided into six main types 1 reticulate 2 tuberculate 3 vesiculose 4 colliculate 5 undulate or 6 poroidalveolate Seed surface patterns are mostly congruent with molecular phylogenetic relationships A reticulate surface pattern is diagnostic of eg Lysimachia subgenera Palladia and Hawaiian Lysimachiopsis Mapping seed characters onto a recent phylogenetic tree reveals that they provide potentially synapomorphic character states for various subclades of Lysimachia Salient examples include a rugose seed shape which turns out to be synapomorphic for the clade comprising the genus Pelletiera plus Asterolinon linumstellatum and a spongelike outer seed coat layer which characterizes a clade with Lysimachia vulgaris L thyrsiflora and L terrestris with an analogue that apparently evolved in parallel in Trientalis europaea We also discuss possible habitat factors that may have favored the independent evolution of particular seed types such as winged seeds in various lineages
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