MG Hirsuteness - Whats the advantage?

Whilst in school I was taught to look at attributes of things as evolutional advantages or disadvantages. Pretty much everything we see from an evolutional point of view is an advantage as disadvantages don't last very long in the gene pool.

Upon perusing my many macro pictures of morning glory I began to wonder why some are very hairy and some not. It occurred to me that the hairy ones might have originated in rather dry climates and produced hair to collect dew for hydration or to direct rain to where it is needed most or actually keep water droplets from touching vulnerable parts. I also thought that the hairs might be some sort of armor against bugs as well, making it difficult to get to the yummy parts.

The picture is a bud of a very hairy Sunrise Serenade which got me thinking about hirsuteness again. So, whats the advantage?


X

I was wondering last fall, looking at the seed pods, if certain varieties were more hirsute than others or if it just varied from plant to plant. The blooms were long gone, but I found a whole range from smooth to very hairy pods & sepals.

Here are some large, dark, and very hairy pods:

and here are some pods at the other end of the spectrum -- smaller, paler, and nearly hairless.

As far as I know, the mix along my fence row of MGs was all I. purpurea... is it possible to ID different cultivars by their pods?

(I know this is a bit off the original topic -- but I've also got the "what's the advantage" question percolating away...)

The hairyness in the pictures are confined to the sepals and are probably incidental. It would be interesting to go back and compare the hairyness of the two different plants. My guess would be that the 2nd one was probably not as hairy.

I am sure there are indicators of genus in the shape of pods and perhaps species by looking at the sepals.

X

This message was edited Mar 24, 2007 4:50 PM

My recollection (sorry, no photo evidence) is that the stems and what remained of the leaves on these vines matched the hairyness (or un-hairyness) of the sepals...

I'm sure the hairs must make it more difficult for sucking/chewing insects to reach the tasty surfaces of the plant. African violet leaves can become very hairy as a response to the presence of cyclamen mites, so that may be an adaptive/defensive response.

X - it looks like you've answered most of your own questions...

The degree of hirsuteness has been asociated with humitity and temperature regulation as well as defensive mechanisms against herbivores...the same basic functions also apply to the degree of hirsuteness of the seeds...

The hairs are often associated with glandular structures which may secrete various types of repellents and/or attractants...there are also different types of special glands that are not clearly associated with hairs...

Ipomoea cordatotriloba has more hairs in the higher latitudes and is mostly hairless (Ipomoea cordatotriloba var. torreyana) the closer the wild plants occur to the equator...


critterologist - The presence or absence of any hairs and the exacting characteristics of any hairs on the fruiting parts of Convolvulaceae is a major key in determining identities...

The characteristics of the fruiting parts are used in conjunction with the structural features present on other relevant parts of the plant e.g.,leaf and stem characteristics,root structure and overall habit to determine taxanomic identity...although recent genetic analysis does not always support the traditional structural keys...

There's always something thought provoking for those who enjoy thinking...

TTY,...

Ron

Ron... so, are my pods with the hairy sepals and those with the smooth sepals both from I. purpurea, or did I have another species in my mix?

critterologist - It's usually alot easier to determine identity on living material as dried out parts incur distortion that makes ID's more difficult,but,I'd say the darker pods here
http://pics.davesgarden.com/pics/critterologist_1174766432_891.jpg
look like Ipomoea nil
and the lighter pods here
http://pics.davesgarden.com/pics/critterologist_1174766486_118.jpg
look like Ipomoea purpurea...

If you still have the pods and can take a closeup of the seeds for comparison >I'd like to see what they look like...

TTY,...

Ron

The only pods I've seen that actually have hair on them are the I Grandifolia. Otherwise it always seem confined to the sepals.

X

X, your photos are amazing. The detail is phenomenal.

Joanne

Thank you Joanne. Most of the credit should go to the camera, a Sony DSC-H5. It allows me to get up close. You can check out my web page to see more if you wish.

www.xeramtheum.com

X