Field of Science

Little non-showy flowers abound in the spring - look closely.

Most people fail to notice flowers that are associated with wind pollination because generally they lack showy flower parts.  Sometimes people notice the pollen-producing flowers if they are aggregated together to form long dangly catkins or aments.  At one time botanists thought that the rather cone-like aments were primitive because they were more like the cones of conifers.  But this idea was falsified in the early part of the 1900s.  So people notice the long dangly catkins on my filbert, Corylus americana, but fail to see the small but rather showy pistillate flowers.  Actually the only part you can see are the bright red, somewhat feathery, stigmas that stick out of the buds to pick up pollen.  So here you are both types of flowers, dozens of pollen flowers and 2-3 pistillate flowers.  TPP does not like calling them male and female although that is common enough usage, but wrong.  Lots of temperate deciduous trees use wind pollination; they flower in the spring before leaves expand an get in the way of pollination.  Welcome to the early allergy season.  


Roger Latour said...

Two questions:

If wind pollinated (not disputing the fact...) why are the stigmas so brightly colored?

And you got me curious: Why is it wrong to call them male and female?

Anonymous said...


the red colour in the style (sometimes pink or purple) is due to anthocyanin pigments. These are known to have a UV protective role in some situations. It seems reasonable to assume that this might be their function here. Interestingly, style pigmentation is variable in Hazel(it can be yellow) but red pigmentation is closely linked genetically to self-incompatibility. So red coloured 'female' flowers require cross pollination.

I am sure that the Phactor will explain the male/female flower problem....he did post on it some time ago.


Roger Latour said...

I didn't know about that UV protection. This brings another question though: why some flowers requires it and some don't!

It is also interesting that self-incompatibility would somehow (who for!?) be signaled by pigments.

The same bi-modal (red/yellow) pigmentation is to be found in Silver Maple (Acer saccharinum). Perhaps this is an all-together different phenomena: introgression from Red Maple?

If you have a link to the male/female flower problem, I'd be grateful. Thanks!

The Phytophactor said...

Almost all stigmas of wind-pollinated trees are red like those above, and sometimes certain glandular areas, nectaries, a red also. Pigmentation might be related to that function somehow but TPP doesn't know. I'll consult my book on plant pigmentation by David Lee, but it's in my office right now. This particular filbert is not self-incompatible. The male/female thing is a bit tricky to explain, but here's a link to a partial explanation.

Roger Latour said...

I had a faint memory of having read something somewhere about that male/female thing. It was on your blog!

Thanks for the refresher!

The Phytophactor said...

The PHytophacter exists to explain such things, so you are most welcome.