Tuesday, February 28, 2012

Hellebores under the covers

I posted a photo of my garden's first Hellebore flower of the season a few weeks ago.  Now the plant is covered in blooms.  I like this plant more and more every year.  Now, I am finding out the flowers are really pretty interesting from an intellectual standpoint, too.

Ken Druse in his book Planthropology writes this about the hellebore:  "The female stigma of a hellebore flower is ready to accept pollen from another flower a week or more before its own male anthers have produced their fertile grains.  Even before the flower opens, bees push their way into the swollen buds in search of pollen, which they do not find, but deposit some from the last ripe anthers they visited."  This is described as a strategy to avoid self-pollination, to keep mixing up the gene pool as much as possible.  

The photo above shows several hellebore flower buds.  The top bud is tightly furled, and I doubt a bee would be able to force its way inside.  The middle bud is a bit looser.  The petals are still closed but not so tightly and there is empty space inside.  I guess this is the stage that Druse is talking about.  The lower flower was also just a bud, not an open flower, at a similar stage to the middle one, when I forced open the petals and peeled one back so I could take a look inside.  You can see the anthers clustered close together, with the five pistils sticking out the center.  If you look back at my earlier post, you'll see the anthers are much more spread out.  It seems to make sense that when they are producing pollen they would be more spread out.  I don't see anything noticeably different about the female parts. 
Avoiding self-fertilization is a good strategy, but hellebores are prolific self-seeders, and although this is  the only plant I have that has produced flowers, I found many seedlings of it this past summer.  Perhaps my neighbors have some hellebores close by, but I think it's much more likely that the plant does self-pollinate when necessary and this strategy is just a way to give pollen from another plant (or another flower on the same plant?) better chances.  The last photo shows the faded first flower of the season, the same as the one pictured on February 15.  Now all its anthers have fallen off, and the ovary at the base of the stigma appears to be beginning to swell.  Maybe I'll get more new plants again this summer!