November 8, 2015
TROPICAL STICKLEAF STICKING TO EVERYTHING
Some interesting botanical sleuthing got started this week when some slenderly club-shaped, inch-long (3cm) items turned up sticking to hairs on my legs and arms, as shown at http://www.backyardnature.net/n/15/151108mu.jpg.
In the picture's top, right corner the narrow, pointed, hairy, fingerlike objects are a flower's dried-up sepals, so the club-shaped thing has to be a maturing ovary or fruit. Moreover, since the sepals arise atop the fruit and not below it, the fruit is one of that minority of species whose flowers produce "inferior" ovaries -- ovaries with sepals, petals and sexual parts at their tops instead of the more common location at the ovaries' bottoms. This was worth noting because it automatically excluded most flowering-plant families from consideration.
When plants producing the sticky ovaries were tracked down I was surprised, because they looked like what's shown at http://www.backyardnature.net/n/15/151108mv.jpg.
Earlier when I'd passed those plants I'd not given them a second look because, with such flowers bearing five orangish-yellow petals, it looked like one of the weedy, hard to distinguish mallow species, and I figured I'd already identified all the ones in this area. But mallows, which are members of the Mallow or Hibiscus Family, don't produce inferior ovaries. Looking closer at a flower I confirmed that the sticky fruit could be nothing but a a classic inferior ovary with its sepals, petals and sexual parts arising atop the ovary, like a hirsute cucumber, as shown at http://www.backyardnature.net/n/15/151108mw.jpg.
However, a peep into the blossom seemed to insist that the flower really was a mallow, because it looked like its numerous stamens united at their bases, surrounding the female part, as shown at http://www.backyardnature.net/n/15/151108mx.jpg.
It wasn't as confusing as it sounds because in botany it's a big deal whether a flower has an inferior or superior ovary, so it was clear that, despite outward appearances, our plant had nothing to do with mallows. Looking for more features of the mystery plant I saw that on mature plants the fruits were held at the tips of long, gangling stems -- the better to bring the fruits into contact with hairy mammals -- as shown at http://www.backyardnature.net/n/15/151108my.jpg.
A very close look at the fruits' spines revealed an unusual kind of grappling structure fixed atop each spine, shown at http://www.backyardnature.net/n/15/151108mt.jpg.
Instead of simple hooks, the spines' tips bear four or five backward-pointing points that catch on hair or fiber.
Since only a minority of plant families produce flowers with inferior ovaries it wasn't hard to figure out that our plant belonged to the small, little known, New World Loasa Family, a family of 15–20 genera and about 200–260 species, native to the Americas and Africa. It's a family known especially for the peculiar hairs investing its species, and sometimes the hairs are stinging ones. In the Yucatan we host two members of the Loasa Family. We've already looked at the other one, a vine bristling with hooked hairs, Gronovia scandens, profiled at http://www.backyardnature.net/yucatan/gronovia.htm.
This second species is MENTZELIA ASPERA, distributed in fairly to very dry places from southern Arizona through Latin America to Paraguay in South America.
The US Department of Agriculture seems to have settled on the English name Tropical Blazingstar for Mentzelia aspera, but I see nothing blazing-starish about it. Another English name sometimes used is Tropical Stickleaf, and that's fine, though it's the fruits that stick and not the leaves. The Spanish language supplies lots of names, including the evocative Amor Seco, meaning "dry love," and the homey Lagaña de Gato, a gato being a cat and lagañas being those dry, crusty grains that sometimes turn up at the corners of your eyes after a long night of sleep.
Traditional healers in Mexico use the plant variously as a medicine -- to encourage fertility in Guanajuato, to expel the placenta during childbirth in Puebla, and other such uses. It seems to be a plant that has caught people's attention, maybe as it caught mine.
Often in the Newsletter I've expressed astonishment at the many different kinds of morning glories found in this area. Morning glories are viny members of the Morning Glory or Sweet Potato Family, the Convolvulaceae. Since the Maya tend to regularly chop down and burn the forest, there are plenty of standing dead trees and short trees and bushes perfect for morning glories to climb over, sometimes forming large areas where everything is smothered beneath them.
Happily, I continue to find new morning glory species. For example, this week the exceptionally hairy one turned up shown at http://www.backyardnature.net/n/15/151108mm.jpg.
Not only the abundant long, stiff and somewhat orangish hairs but also the compound leaves with leaflets arising from the petiole tip (digitately compound) make this species distinctive and easy to identify. The flowers however, are structured like those of a lot of morning glories, as shown in a broken-apart blossom at http://www.backyardnature.net/n/15/151108mn.jpg.
This is the Hairy Woodrose, MERREMIA AEGYPTIA, despite the Egyptian part of the name a native of Mexico and tropical America in general, but invading much of the world's tropics. The genus Merremia is a lesser known genus, set apart from better known genera largely because of its pollen grains. Unlike the big morning glory genus Ipomoea, which this plant looks a lot like, Merremia flowers produce pollen grains without spines. Also, anthers in Merremia flowers tend to twist, though in our blossoms they were fairly straight.
This morning glory's twining stems are especially tough, in fact in some African countries being used to tie together poles in house frames. In certain parts of Africa the dried leaves are used as a dressing for burns. The plants must contain some kind of powerfully active compound, because it's known to cause diarrhea in small stock when large quantities were eaten.
SPURRED BUTTERFLY PEA
In this area during much of the rainy season/summer, along roads and other open places, frequently there's a vine with leaves divided into three leaflets and bearing large flowers structured like typical Bean Family blossoms, except that they're upside-down. It's the Butterfly Pea, shown at http://www.backyardnature.net/yucatan/butt-pea.htm.
I haven't seen that species in blossom for awhile, but nowadays a very similar vine is blossoming, also with leaves consisting of three leaflets and bearing upside-down Bean-Family-type flowers, as shown at http://www.backyardnature.net/n/15/151108ce.jpg.
Comparing the two vines we get to enjoy two "variations on the butterfly pea theme," for this is a second butterfly pea species. This later-flowering one is smaller and more delicate that the other. It's the Spurred Butterfly Pea, CENTROSEMA VIRGINIANUM. Centrosema species sometimes are distinguished by the shape of their sepals and the bract below the calyx, so a photo showing that is at http://www.backyardnature.net/n/15/151108cf.jpg.
You can see from the species name virginianum that this species also occurs in the US. In fact, I knew it well during my early botanizing days. It's distributed widely from the eastern US south through Mexico and Central America to Argentina in South America, plus the Caribbean islands, and it's been introduced in tropical West Africa.
You might wonder why a genus would turn its flowers upside-down -- and if you need a review of how a right-side-up bean flower presents itself, look at the Kudzu flower at http://www.backyardnature.net/fl_beans.htm.
If you remove one side of our present butterfly pea flower's top "hump," it'll start to make sense. What's inside our flower's hump is shown at http://www.backyardnature.net/n/15/151108cg.jpg.
Imagine a pollinator landing on the large flat surface below the hump -- the "landing pad." Dark lines on the landing pad converge toward a pale area beneath the hump, so the pollinator is drawn there. As the pollinator forces its way under the hump, the stamens with their filaments fused into an arching cylinder shove their anthers down to dust pollen onto the pollinator's back. Therefore, it's all designed to facilitate pollination.
Moreover, in that picture, notice the small, pale stigma extending just beyond the stamens' anthers. It's positioned to be the first sexual part touched by a visiting pollinator, to receive pollen from other flowers before the stamens bestow their own pollen, to be carried to another blossom
So, one advantage of butterfly pea flowers being upside-down is that the large petal known as the "keel" or "standard," which usually just rises at a blossom's top, in this upside-down condition forms a fine landing pad.
Also in the hump picture, notice that one stamen stands apart from the others, whose filaments are joined into an arched cylinder surrounding the style. In the Bean Family very often you meet this configuration of 9 + 1 stamens. Such stamens are said to be "diadelphous." I'm unsure what the advantage to having diadelphous stamens might be, unless it's simply to provide a second opportunity for a visiting pollinator to be doused with pollen. Interestingly, most Bean Family members with flowers all grouped into a single cluster with no outlying members are mostly pollinated by organisms visiting to eat pollen, while blossoms attracting pollinators searching for nectar normally produce diadelphous stamens.
MEXICAN BEAUTYBERRY WITH BLACK FRUITS
As is the case now, in October of 2010 at woods edges along roadsides in the Pisté area there were numerous shrubs with dense, attractive clusters of white fruits. The shrubs were Mexican Beautyberries, Callicarpa acuminata, and you can see their handsome flowers and fruits at http://www.backyardnature.net/yucatan/beautyb.htm.
Something noted on that page is that "Callicarpa acuminata nearly always is described as producing very dark purple or black fruits, while our bushes' fruits have been white for two months and show no sign of darkening." For the last five years I've wondered about that.
Nowadays more information about Mexican Beautyberry is available. The species' fruit picture posted by CICY, the Yucatan's Center for Scientific Investigation, shows white fruit, and the Wikipedia author for the species admits that sometimes white fruits are produced. And this week I found Mexican Beautyberries bearing black fruits mingling with those producing white fruits, which is a situation I've not seen mentioned in the literature.
You can see a nice cluster of elderberry-black fruits of the type apparently most common over the rest of the species' distribution at http://www.backyardnature.net/n/15/151108cc.jpg.
Green fruits maturing directly to dark purple or black with no white intermediate stage apparent are seen at http://www.backyardnature.net/n/15/151108cd.jpg.
Most authors simply ignore our white-fruited plants, often calling Callicarpa acuminata Black Beautyberry. An online database for taxonomy, Tropicos, lists four varieties of the species, without describing them, so maybe we have mingling varieties here. That would be unusual, though, since usually mingling varieties interbreed with one another, and tend to form intermediate organisms, not intermingling ones.
In the old days the Beautyberry genus Callicarpa was placed in the Verbena Family but nowadays usually it's assigned to the Mint Family, though its herbage doesn't smell minty and the fruit isn't deeply four-lobed.
While looking for medicinal uses of Callicarpa acuminata, in Google Books I stumbled upon a 2003 publication by Marianna Kunow, published by UNM Press (University of New Mexico), entitled Medicine: Traditional Healing in Yucatan. It describes the practices of curanderos, or traditional herb doctors, right here in Pisté. Kunow writes of Callicarpa, "to cure diarrhea and vomiting. Soak a bunch of leaves in cold water with a little sugar. Drink daily until cured." The local Maya call the bush X Pukim
STORY ABOUT A NAMELESS SNAKE
In 2006 near Telchac Pueblo here in the Yucatán, and again in 2011 on the road leading into Hacienda Chichen, I photographed incredibly small snakes, sometimes known as thread snakes. I had problems identifying them but ended up calling them Goudot's Thread Snakes, Leptotyphlops goudotii, which no one challenged for years.
But then this year when I was at Yaxunah, visiting a neighboring town with Internet connection, a letter came in from a specialist in thread snakes at a university in the US, saying that my page needed to be updated. However, I only got to scan that mail's subject box and return address, before it and all other mail was deleted by a computer virus. This was when I was downloading mail only every few weeks, so many mails were lost.
Since regaining access to the Internet I've been trying to track down the person who sent that message. Finally this week I found him, but he asked that certain information be kept secret, since he's months from publishing his work and doesn't want his data circulating before it's issued officially.
The part of the story I can pass on is that the thread snakes I photographed here in the north-central Yucatan belong to a species not yet recognized by science. They have no official name. In the past, sometimes they were noticed and collected by several people, but they were misidentified as another similar species, which was the case with me. This new species constitutes a small "island population" geographically isolated from similar species. The individual from which the description of the species will be formally published in Latin, the "type specimen," was collected here at Chichén Itzá.
So, how about that? We've run into something very interesting, but didn't know how interesting it was until someone told us, which often is the case. You can see my pictures -- one taken back when I didn't have a good camera and the other a snapshot taken before the snake disappeared without my getting the usual close-up -- on our "Nameless Thread Snake" page at http://www.backyardnature.net/yucatan/nameless.htm.
FEATURED ESSAYS FROM THE PAST:
"Frog Eggs & Religions," from the February 8, 2004 Newsletter, at http://www.backyardnature.net/n/p/040208.htm
"Persimmon Pudding & My Big Gamble," from the May 24, 2009 Newsletter, at http://www.backyardnature.net/n/p/090524.htm
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.