As I mentioned before, the winter has presented me with wonderful opportunities to observe some interesting characteristics of the ferns and lycophytes. I’ve been aware of growth constrictions in temperate lycopods for a long time, but I had to see these evergreen plants growing in the snow to actually process the information. Constrictions on the lateral branches result from a change in growth speed through the seasons of the year (reminding us of the annual rings of trees).
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- D. obscurum – habitat1
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- D. obscurum – habitat2
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- D. obscurum – habitat3
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- D. obscurum – habit1
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- D. obscurum – habit2
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- D. obscurum – habit3
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- D. obscurum – growth constriction adaxially
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- D. obscurum – growth constriction abaxially
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- D. obscurum – growth constriction
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- D. obscurum – stem
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- D. obscurum – strobilus
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- D. obscurum – strobili
Yes – these are really cool. Interesting that some species form them, and others do not. I imagine it must be the result of differential growth restriction among taxa. For example, constrictions are a really good character for some Diphasiastrum species. You also see it in some of our Huperzias, not to mention Dendrolycopodium.
Good observation!