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The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Tuesday, February 24, 2009

Sex determination in Dicranum

My name is Frida and I started my PhD project a couple of months ago, which is about dwarf males in Homalothecium lutescens. I have recently finished Robin W. Kimmerers book "Gathering Moss" and find it excellent, I feel so privileged to be able to work with these fantastic organisms. But there is one thing that puzzles me. In the chapter "Sexual Asymmetry and the Satellite Sisters" she writes (about Dicranum):

"When a fertilized female produces spores, those spores are without gender. Each one is capable of becoming a male or a female, depending on where it lands. If a spore drifts to a new rock or log that is unoccupied, it will germinate and grow up to be a new full-size female. But should that spore fall onto a patch of Dicranum of the same species, it will [...] become trapped there, where the female will control its fate. The female emits a flow of hormones which cause that undecided spore to develop into a dwarf male..."

Has anyone heard of this "physiological sex determination" in Dicranum? Or anything in general about complex sex expression in Dicranum? The closest I get is the 1956 dissertation by Loveland but even there he cannot confirm that spores that germinate on "normal" substrate all become females, only that they look like sterile females. I have e-mailed Kimmerer about the reference but she can't find it.

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