Saturday, June 5, 2010

Asplenium pinnatifidum

Another new fern for me in Governor Dodge was Asplenium pinnatifidum (this was a great field trip!). This is another exciting one for several reasons. First, it's a polyploid, and I have a soft spot for polyploids - the group I study has lots of them, and they're just neat. Second, over a year ago I wrote about finding four species of Asplenium on another field trip, and that it was cool because they were all members of the "Asplenium triangle" of hybridizing and interrelated Asplenium species in North America. Well, A. pinnatifidum is another member of that complex. It is thought to be an allotetraploid (meaning that it's two genomes were contributed by two different parental species). The triangle figure is below, modified from the figure in the Flora of North America, volume 2. In the figure, the solid circles represent diploid taxa, the open circles are fertile polyploids, and the triangles are sterile hybrids. A. pinnatifidum falls on one of the lines connecting two diploids, which are its two putative parents, A. rhizophyllum and A. montanum:

Below are the A. pinnatifidum individuals we found at Gov. Dodge, as well as a habitat shot of the sort of rock crevices we found them in. They weren't in the best shape, and apparently some of them had actually been out-planted there in an attempt to rejuvenate an existing, natural population. Hopefully this was just a bad year or season, and they'll pick up again soon. It's neat to come across such a rarity.

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