(Salix is related to an ancient name for Willows. Caroliniana is geographic.)
Premature post-plop this week due to attending the Orange Bowl in Miami tomorrow preempting usual blog composition time. Go Blue. You can’t spend much time in Kiplinger Nature Preserve, or anywhere near water wordwide without Willows. There are over 500 species just about everywhere. This is the third Willow appearance in the blog. In earlier episodes CLICK and CLICK we looked at them as sources of salicylic acid. Two remarkable facts reappear from hosts of blogs past.
- Salicylic acid (named for the Willow genus Salix) is essentially aspirin. Ancient patients around the world chewed two Willow sticks and called in the morning.
- Salicylic acid exists in Willows and in all or most other plants as an airborne hormone functioning to “spread the word” of pathogenic attack, urging nearby plants into a defensive mode. Paul Revere hormone: the fungi are coming! The signal travels on the breeze. Now, a plant would have no “interest” in warning other separate inviduals. Plants have no kindly intentions so far as I know. BUT: Perhaps Willows super-produce salicylic acid because some species spread into huge clones, in a genetic sense a single individual sprawled across the marsh. When you “warn” the surrounding stems you are warning yourself.
Today a new chapter on Willows, their sticky oozings. To ease into the stickum, first a little evolution. If botanists of an earlier era got it right, the history of Willows seems to go like this:
Once upon a time, the ancestors of Willows depended on insects for pollination, possessing the trappings associated with buggy blossoms: fragrance, colorful petals, nectar. But somewhere along the line ancestral Willows ditched all that and switched to wind, as is true of many trees.
Modern Willow flowers look like standard wind-flowers, arranged into spikes (called catkins) with no petals to turn a passerby insect’s head. Usually the male and female flowers are on separate trees—so often seen in insect-pollinated species.
That’s all good until we notice bees and wasps visiting the Willow flowers with gusto. Buzz off. You guys aren’t supposed to be here! Or could it be that Willows decided ixnay on the indway, and returned to insect-pollination? That’s what botanists think.
What’s weird about resuming the insect habit is that Willows had already given up their advertising equipment, and remade it “from scratch.” Look closely, there is color, not in petals as in the distant past, but now in bright yellow anthers (pollen sacs) on the male flowers. The female flowers do not have much color, however. Scent? The male flowers smell sweet. If the females do, my sniffer has trouble detecting it.
New bright color. Scent. Does it seem the male flowers have regained more bug-attractiveness than the females, at least as a human sees it? The male flowers do appear to draw a lot more insects. The male bush can be buzzing. Not sure why this disparity is so, but it seems (repeat, seems) maybe the male flowers vastly outnumber the females, and thus load up hordes of insect pollen-carriers, only a fraction of these required to visit the relatively sparse female flowers.
The interesting part of an insect dependence mulligan is renewed nectar. Both the males and females have it, but oh oh, here is a problem, isn’t nectar usually made on petals or on the ovary of most flowers? Yes, but Willows have no petals, and the bee-loved males have no ovaries. In both the males and females each flower has one or two nectar glands outside flower’s base, oddly positioned. The oddness is best explained as new, replacement nectar glands accommodating the late return to feeding insects. They are substitutes. Let’s say I throw away my stylish Macys hat, then move to the hills and get cold ears. I make a new hat from skinned skunk.
Now to stretch it all to the point of pain. No evidence. Just a hunch about how the trees managed to remake nectar glands at the flower bases. Willows are glandular all over. You want a gland, we have plenty. There are so many glands on a Willow, providing the flower bases with new ones seems “only natural.” Read on:
Most notably, every tooth on every sawtooth leaf has its own gland, a hundred glands per leaf, also on the stipules. Botanists have pondered the purposes of these leaf-tooth secretions, and maybe they attract defensive insects to the foliage, or maybe they deter herbivory, and perhaps they coat the tender leaf margins in protective varnish, and ossibly they secrete excess water. Perhaps combinations of these functions differ in different species. Who knows, maybe the leaf goo helps volaralize that salicylic acid. In any case, Willows are oozing all over, so if a part of the plant, flower bases for instance, needs nectar to get back into the insect game, it may have been pre-ordained. Repeat, this is a hunch and only a hunch. (A good one though.)
In one intensively studied species, the tooth-tip gland extrudes its product in a thin filament, like linguini out of a pasta machine. CLICK HERE to see the spaghetti.
Why does it do a thing such as that?