Issued in Río Lagartos, on the northern coast of
Yucatán, MÉXICO
in Ría Lagartos Biosphere Reserve

June 14, 2015

I was camping in the salt marshes where during most of the year there's shallow water but now, despite recent rains, it's still dry and open. Here and there dense tangles of Buttonwood Mangrove and Poisonwood formed islands of woody vegetation, or hammocks. That morning as the sun came up an oriole landed in a Buttonwood beside my tent, as shown at http://www.backyardnature.net/n/15/150614oo.jpg.

In this area whenever you see an orangish (not yellowish) oriole with an orangish back, you know two things: First, it's a mature male, because females and immatures are more yellowish. Second, you need to pay close attention, because we have two very similar species in which the males have orangish backs, and one of them, the Orange Oriole, is endemic just to the Yucatan Peninsula. The other, the Hooded Oriole, is much more generally distributed, found from the southwestern US through most of Mexico to northern Belize. So, which was this?

Most of us find it hard to distinguish the two species if the birds are yellowish immatures or females, even when they offer good views and stay still. In those birds the field mark to look for is the Orange Oriole's straight bill, to be compared to the Hooded Oriole's slightly down-curved bill. So, in the above picture, is the bill straight or curved? A better look is provided at http://www.backyardnature.net/n/15/150614op.jpg.

It's straight most of the way, but then curved toward the tip. Field guides show Orange Oriole beaks a little curved at the tip, so the beaks aren't absolutely straight, but Hooded Oriole beaks aren't really too curved, either. Also, the black face masks on Orange Orioles are a little less extensive than those on Hooded Orioles, but that's hard to judge. Other such vague, intergrading differences also could be mentioned, which helps someone familiar with the birds, but leave beginners wondering.

Happily, when you have male adults like ours, all these ambiguous field marks can be ignored, for only the adult male Orange Oriole's back is orange; adult male Hooded Oriole backs are black or blackish. Our orange-backed bird is definitely an endemic Orange Oriole, ICTERUS AURATUS, whether its bill is straight or not, or its face mask more or less extensive.

This endemic species is fairly common in our area wherever open areas with scattered trees occur. The farther south in the Peninsula you go, the less common they become. At the Inaturalist.Org website the Spanish description of the bird describes the Orange Oriole as the only species within the genus Icterus that nests colonially. In the field they often wander with other oriole species.

Orange Orioles look like Hooded Orioles, but their song is a pretty, varied series of clear, plaintive whistles similar to the Altamira Oriole's.

Wit such similar-looking species, sometimes you wonder whether the two forms really deserve to be called distinct species. In this case, the Orange Oriole's behavior makes it clear that it's a real, separate species.


We've already looked at Black-necked Stilts. However the other morning one walked by so gracefully and prettily reflected in the calm salt-marsh water that I just had to photograph him, as shown at http://www.backyardnature.net/n/15/150614st.jpg.


I've mentioned that sometimes masses of minnow-sized, grayish-brown fish appear at the water's surface in pools, such as where the estuary's brackish water flows back and forth beneath culverts in the levee south of town separating the estuary and the mangroves. We've seen that these schools are mostly Yucatan Gambusias with a few Yucatan Mollies. Rainwater Killifish, LUCANIA PARVA, also are part of the mix, shown at http://www.backyardnature.net/n/15/150614lu.jpg.

These look a good bit like Yucatan Gambusias, which you can compare at http://www.backyardnature.net/mexnat/gambusia.htm.

But notice that the Rainwater Killifish's mouth is narrower, more "puckery," and that each of the killifish's scales is two-toned, highlighting each scale. The species is very flexible in its water requirements, occurring in marine, brackish and freshwater. FishBase.Org and similar sites describe the species as living coastally from Massachusetts south to Mexico's northern Gulf of Mexico, which doesn't include here. However, the 2010 Peralta-Meixueiro and Vega-Cendejas work I often refer to reports them as present in Ría Lagartos Estuary, in both seawater and brackish estuary water, as well in hypersaline waters at the estuary's eastern end.

Rainwater Killifish feed on tiny crustaceans such as copepods and cyclopoids, mosquito larvae, small worms, and mollusks. Our fish were about 1½ inches long (4cm), and that's within the range of adult lengths.

And who knows why the fish is named "Rainwater"?


In last month's May 31 Newsletter we looked at young Yucatan Mollies with just a sprinkling of powder-blue spots on their tail fins, shown at http://www.backyardnature.net/mexnat/poecilia.htm.

Nowadays I'm seeing larger, more colorful fish, the powder-blue spots now covering all their tail fins, the bodies' white spots more vivid, and now their entire front ends are flushed with orange, as seen at http://www.backyardnature.net/n/15/150614po.jpg.


On very thin soil atop limestone in the transition zone between savanna and mangrove nowadays there's a scrubby, super-spiny, feathery-leafed, small tree that even at a distance looks like it could be nothing other than an acacia. Usually its branches mingle with those of similarly gnarly, similarly spiny neighboring trees, but one individual about belly high grew in a savanna/cow-pasture producing the amazingly wide, flat-topped form shown at http://www.backyardnature.net/n/15/150614bm.jpg.

Up close it's the big, white, broad-based spines that get your attention, as you can see at http://www.backyardnature.net/n/15/150614bh.jpg.

In that photo, something else to notice is that the flowers are orangish-yellow and that they occur in unusually small, spherical heads. The twice-compound leaves also are strikingly small. You can see how small the heads are in a picture with my finger in the background for scale at http://www.backyardnature.net/n/15/150614bk.jpg.

Its one of the "ant acacias," an acacia that does what it can to make ants feel at home, probably so ants will rush out and bite anything thinking about nibbling the leaves. A close-up of a leaf with numerous pinnae and four dimpled, nectar-producing glands on its petiole, with an ant supping at the lowest gland, is shown at http://www.backyardnature.net/n/15/150614bf.jpg.

Another shot closer up showing an intently feeding ant and sharp stipular spines at a petiole base is at http://www.backyardnature.net/n/15/150614bj.jpg.

Last season's brown, dried-up legume husks remain on the tree, tightly curled into such unkempt-looking clusters that you wonder why the tree keeps them, shown at http://www.backyardnature.net/n/15/150614bi.jpg.

The tree's well armored, splotchy trunk is shown at http://www.backyardnature.net/n/15/150614bl.jpg.

So many acacia species exist -- ten taxa listed for the Yucatan Peninsula -- that identifying them can be tricky. Luckily I know an Acacia expert in Germany, Dr. Wolf-Achim Roland, who seems happy to look at acacia pictures, so I just sent our pictures off to him.

Of course it's dangerous to identify things just from pictures, but Dr. Wolf figures we probably have ACACIA GLOBULIFERA, which he calls Vachellia globulifera, because he's one of those who believe in splitting up the noble, old, huge and well-known genus Acacia into hard-to-remember genera like Vachellia. I continue to use Acacia because I think the genus is so well established that it deserves to stay together, no matter what the genes say, and many experts believe the same. You can read all about the big "Acacia Name Change Debate" here

Anyway, Acacia/Vachellia globulifera sometimes is known as the Globular Acacia, and it occurs from southern Mexico to Honduras.

Acacias are members of the Legume Family, and as such possess mycorrhiza on their roots that fix atmospheric nitrogen so that other living things can use it. Bees were buzzing the flowers as I photographed, and the soil in that area was so thin atop the limestone that all plants provided a great service just by being there, holding what little soil there was in place, photosynthesizing and producing cool shade instead of yielding their spots to naked, lifeless, hot rock.


Even before last week's first good rain of the rainy season, already many woody species were flowering and/or issuing new leaves. Now that it's rained, so many plants are greening up that it feels like a very hot spring up north. One robustly flowering small tree or shrub caught my attention this week because I'd never seen it before, and its red clusters of small flowers were unusual.

On very thin soil atop limestone, at the edge of the mangroves where during the rainy season sometimes the area must be flooded, its gnarly branches mingled so indiscriminately with those of other usually-spiny woody species that any portrait of the plant would just show a jumble of zigzagging limbs. However, a branch seen against the sky was a pretty thing, shown at http://www.backyardnature.net/n/15/150614en.jpg.

The clusters of red flowers, so eagerly patronized by our aggressive Africanized honeybees that I would get near some trees, are shown at http://www.backyardnature.net/n/15/150614eo.jpg.

The spherical objects in that picture are unopened flower buds. Each open flower consists of numerous stamens, no corolla, and four calyx lobes, or sepals. No female parts -- no pistil with its stigma, style and ovary -- are visible, so these are unisexual male flowers, and on this and neighboring trees no female flower could be found.

At this point I realized that this might be something special, so I began "doing the botany" more seriously than usual. Here come lots of details, so hold on, or skip to the next entry... :

After searching maybe a dozen trees, finally a female flower was found on a tree with no male flowers. The female flower bore no stamens but rather an asymmetrical ovary with two very long, hairy stigmas atop a very short style, as shown at http://www.backyardnature.net/n/15/150614ep.jpg.

Another plant, hardly knee high, bore a single, more developed but hard to see fruit amidst its gnarly, lichen-covered branches, shown at http://www.backyardnature.net/n/15/150614eu.jpg.

The capsular fruit, which had lost its stigma lobes, is shown closer up at http://www.backyardnature.net/n/15/150614es.jpg.

The fruit was atop a short stem, or stipe, as shown at http://www.backyardnature.net/n/15/150614et.jpg.

The plant's leaves were immature but a few the size of a fingernail were emerging, and were developed enough to see that when fully formed they'd probably be widest above their middles, bear shallowly eared bases, pinnate venation and shallowly lobed or "crenate" margins, as seen at http://www.backyardnature.net/n/15/150614eq.jpg.

Held against the sky, certain glands and tufts of hairs in the axils between the midrib and veins become visible, as seen at http://www.backyardnature.net/n/15/150614ev.jpg.

Finally, the tree's pale, splotchy trunk showed that, though it didn't bear regular spines, it produced sharp-pointed, small branches that were "spinescent," as shown at http://www.backyardnature.net/n/15/150614er.jpg.

Many hours of looking on the Internet for pictures showing our little tree didn't turn up anything. Because of the unisexual flowers with many stamens and its capsular fruit, I guessed that the plant was a member of the big Euphorbia or Poinsettia Family, the Euphorbiaceae, and so I focused y search on that family. Luckily, a new website providing an interactive key to the world's genera of Euphorbiaceae has just opened up -- one of the best keys like this I've seen -- so I tried it. The key is at http://keys.lucidcentral.org/key-server/player.jsp?keyId=66.

Of the 1078 taxa considered by the key, simply by stating that our plant's sepals were red, the possible options were reduced to 12 taxa. A few more observations, especially that male flowers bore numerous stamens (more than ten) and the fact that our plant was in southeastern Mexico, led directly to one genus, a genus embracing only two species, both endemic only to Mexico, the unheard-of genus Enriquebeltrania. With our plant's leaves widest above the middle and with shallowly scalloped margins, it was clear we had ENRIQUEBELTRANIA CRENATIFOLIA, endemic just to the Yucatan Peninsula.

So, this is a wonderful find, a modest but pretty little tree or bush seldom seen, one who seems fixed on the flowering strategy of producing enormous numbers of pollen-laden male flowers, perhaps on the theory that with so many pollen-dusted bees flying around at least some will bump into the rare female flowers and pollinate them.

What interesting studies could be made on this little tree.


Not far from the Enriquebeltrania crenatifolia trees -- so also on very thin soil atop limestone bedrock that probably is flooded during the rainy season -- a similarly scrubby, much-entangled-with-other-bushes woody plant also was flowering, as shown at http://www.backyardnature.net/n/15/150614a5.jpg.

Up closer I was surprised to see that the tight clusters of little white flowers, exactly as with the Enriquebeltrania trees, consisted of nothing but greenish sepals spreading below clusters of male stamens, as shown at http://www.backyardnature.net/n/15/150614a6.jpg.

The sepals hairiness was unusual so I got a photo emphasizing that, shown at http://www.backyardnature.net/n/15/150614a7.jpg.

Leaves were emerging after last week's first rain of the rainy season, so you can see that they were pinnately veined, had slightly eared bases, that the bases were symmetrical, and that the blades' margins were without teeth or lobes -- entire -- at http://www.backyardnature.net/n/15/150614a8.jpg.

Only three or four of these shrubs were found and none bore female flowers or fruits. Still, with the similarity of the male flowers to those of the Enriquebeltrania trees, I figured that this was probably a member of the Euphorbia or Poinsettia Family, the Euphorbiaceae, so off I went to the wonderful interactive key to the world's genera of that family at http://keys.lucidcentral.org/key-server/player.jsp?keyId=66.

With that key, just by using features clearly seen in the pictures, and the fact that we're in southeastern Mexico, the possibilities were narrowed to three genera of which only one looked anything like our plants, the genus Adelia.

Two Adelia species are listed for Ría Lagartos Biosphere, and of those two species the one with leaves like ours is ADELIA OAXACANA, sometimes in English literature known as the Oaxaca Adelia, Oaxaca being a southern Mexican state and pronounced like "wa-HA-ka."

To firm up the ID, an Adelia male flower on the Internet was found looking very much like ours, with exceptionally long-hairy sepals. That picture appears at http://malpighiales.myspecies.info/taxonomy/term/133/media.

Adelia oaxacana is described as present in arid regions of central and southern Mexico, so it's much more commonly distributed than the Enriquebeltrania trees around it, but where I found it much less common.


We've already met the False Tamarind, what the Maya call Tsalam, LYSILOMA LATISILIQUUM, especially noticeable during the early dry season in December when large, flat, blackish and curiously flaky legumes hang in bunches from their branches, as shown in our picture at http://www.backyardnature.net/n/11/111211ts.jpg.

Nowadays False Tamarinds are flowering prodigiously, their white flower bunches very conspicuous, fragrant and bee-buzzed, as shown at http://www.backyardnature.net/n/15/150614ad.jpg.

Normally the trees' branches mingle with branches of other trees and the tree's form is more or less treelike, but here you can see that when given a chance in our arid climate, instead of competing with neighbors for resources, it likes to sprawl into open areas.

A close-up of its flower bunches, which are pure white when they first develop but fade to yellowish after a day or so, is at http://www.backyardnature.net/n/15/150614aa.jpg.

A flowering head atop a slender stem, or stipe, suggestive of acacia flower heads, is at http://www.backyardnature.net/n/15/150614ab.jpg.

In fact, False Tamarind's flowers and leaves are so similar to those of acacias that I don't know why the two genera are separated, and some experts have wondered that, too. I understand that the main differences are technical features of the legume-type fruits. Another difference might be shown at http://www.backyardnature.net/n/15/150614ac.jpg.

That's a compound leaf's petiole shooting off toward the picture's top, right corner, with a single raised gland on it, rather like petioles of some of the ant-attracting acacia species. But notice the single, yellowish-green, fingernail-like stipule at the petiole's base, arranged horizontally at the picture's middle bottom. That's a bit unusual and not something I recall among the acacias.

Anyway, nowadays the False Tamarind's fresh, green leaves and fragrant, powder-puff clusters of flowers contribute to the landscape's springy feeling.


On very thin soil atop limestone bedrock at the edge of the mangroves a chest-high bush with semi-succulent leaves bore several yellow, plump, plum-like fruits, as shown at http://www.backyardnature.net/n/15/150614ic.jpg.

Biting into the fruit, the juicy flesh was a little acidy, a little bitter, but not bad. However, most of the fruit's interior was occupied by a large, spherical seed, as shown at http://www.backyardnature.net/n/15/150614id.jpg.

Once I saw the seed I realized that this was a bush and fruit that normally I encounter on sandy beaches. It was the Icaco or Cocoplum, introduced on our page at http://www.backyardnature.net/yucatan/icaco.htm.

This shrub's fruits were a little smaller and yellower than I was used to, and the leaves' petioles were reddish, which I didn't recall seeing on other plants. This particular beach-loving plant was in soil that much of the year is waterlogged, but which for the last few months had been extremely dry, and it often happens that plants under drought stress lose some of their green pigments causing remaining pigments to produce different colors.

Several Icaco subspecies and varieties are recognized, and often "coastal forms" and "inland forms" are spoken of. Wikipedia's page for the species refers to a "... coastal form being round, up to 5 cm in diameter, pale-yellow with rose blush or dark-purple in color, while that of the inland form is oval, up to 2.5 cm long, and dark-purple." Also the inland form is described as having reddish leaves. Our reddish-leafed, yellow-fruited individual doesn't match this description, but it's clear that Icaco is a variable species, and we're confirming that.


The big, columnar, densely spiny Sabucán cactus often is seen bearing lumpy, greenish fruits, as shown on our page for the species http://www.backyardnature.net/yucatan/sabucan.htm.

The flowers, however, seldom are seen. Apparently they open only briefly, maybe only for one night, and until now I've been unable to catch one. However, one morning this week one was still open, as shown at http://www.backyardnature.net/n/15/150614pc.jpg.

Even this flower appeared to be closing up in mid-morning.


A week after the first rain broke our long, hot dry season, Rain Lilies appeared, exactly as they did in hot, arid southwestern Texas during our stay there. Moreover, the plants looked the same. You might find it interesting to review the Texas Rain Lily, Zephyranthes chlorosen, at http://www.backyardnature.net/n/h/rainlily.htm.

Now look at the Rain Lilies that popped up from very thin, soil atop limestone bedrock here, at the edge of the mangroves, at http://www.backyardnature.net/n/15/150614ze.jpg.

Closer up we see that, just like the Texas species, this lily's flower tube is extremely long and slender, with its attachment to the stem marked only by a slight bulge where its base is embraced with a brownish spathe, as shown at http://www.backyardnature.net/n/15/150614zf.jpg.

When distinguishing the various rain lily species up north, it was important to notice whether their stigmas emerged from the corollas' mouths, or stayed well within the corolla tubes. A close-up showing that the roundish stigma head of our flower emerges from the corolla tube, just like the Texas species shown above, is at http://www.backyardnature.net/n/15/150614zg.jpg.

In fact, this turns out to be the same species we had in Texas, ZEPHYRANTHES CHLOROSEN, though our Yucatan population seems to consist of a tiny island of them just along the Peninsula's coast. The main population occurs in the south-central US, mostly in Texas and arid northern Mexico, with our Yucatan plants being "disjunct" populations. Who knows how this arid-land-loving plant made the jump across the Gulf of Mexico?

In much of Texas this species is fairly common, at least after certain good rains, but here our populations are regarded as at risk because only four populations are known here, and the populations are widely fragmented. They are not listed for the Biosphere Reserve, so this is a good find.


Beside the coastal road between Río Lagartos and Las Coloradas a chest-high weed was prodigiously flowering and fruiting even though it'd done most of its growing during the very hot, rainless dry season. It's shown at http://www.backyardnature.net/n/15/150614cn.jpg.

This looked like the Horseweed, CONYZA CANADENSIS, commonly seen along roadsides and in first-year abandoned fields in much moister parts of the US. But, up to 40 or more Horseweed species, genus Conyza, are recognized, so maybe this was a special, tropical, look-alike species, and I'd better "do the botany."

First, I looked closer at the plant's flowering area, finding flowering, fruiting, and mature, empty heads all intermingled, as shown at http://www.backyardnature.net/n/15/150614co.jpg  

The flowering heads, typical of the big Composite or Daisy Family, consisted of closely packed, cylindrical disc flowers surrounded by ray flowers with very short, white, flat corollas, all enclosed in a greenish "involucre" consisting of overlapping, narrow bracts, or phyllaries, as seen at http://www.backyardnature.net/n/15/150614cp.jpg.

Something to notice in that picture is that the green phyllaries are hairless, or "glabrous." This feature is very important in distinguishing the various horseweed species likely to be found here, for the other species bear definitely hairy phyllaries.

When a breeze passed by, several tiny, white-parachuted, cypsela-type fruits were blown from their fruiting heads. Some cypselae with their white prachute-hairs, or bristles, are shown on the tip of my finger at http://www.backyardnature.net/n/15/150614cq.jpg.

The plant's leaves were twisty from lack of rain, but you can see their general form -- slender with a few obscure teeth and sometimes developing a lobe or two -- at http://www.backyardnature.net/n/15/150614cr.jpg.

Three horseweed species are listed for the Biosphere Reserve, and one of those is the same Horseweed common along North American roads, CONYZA CANADENSIS. Despite the Canada in its name, Horseweed is native throughout North America from southern Canada south through all of the US into much of Central America, plus it's invasive in much of the rest of the world.

Maybe because Horseweed is a native American plant, America's indigenous people found good uses for it. They ate it, at least its young leaves and shoots, boiled, cooked with other ingredients, or dried for later use. Medicinally the traditional herbal uses are so many -- "antirheumatic, astringent, balsamic, diuretic, emmenagogue, styptic, tonic and vermifuge," one source says -- that you just wonder. Indigenous Americans also boiled it in the waters making steam for sweat lodges, took it as a snuff to stimulate sneezing when they had colds, and burned it to create smoke to ward off flying bugs.

So, this is one of those tough, aggressive, yet useful beings that might survive global warming and all other upcoming human-made disasters. One does well to tip a hat to it and wish it the best.


Even the Salicornias are flowering, a Salicornia being a weird looking, much branched, succulent, salt loving (halophytic) plant commonly found here at the edges of salt marshes and sometimes at the edges of mangroves, as shown among some rocks piled at the mangrove's edge at http://www.backyardnature.net/n/15/150614sa.jpg.

Sometimes Salicornias are known as Saltworts, Glassworts or Pickleweeds, but travelers I meet nowadays seem to be calling them Salicornias so that's what we'll use. They're SALICORNIA BIGELOVII, native to coastal areas of the eastern and southern US and southern California south along both of Mexico's coasts, and Belize.

Salicornia's flowers don't work hard to catch your eye. For example, take a look at some stems terminated by spikes of flowers at http://www.backyardnature.net/n/15/150614se.jpg.

In that picture several stems end in green, cylindrical, spike-type flowering heads, or inflorescences. One inflorescence has a few yellowish, sand-grain sized items attached. A close-up of some of those is at http://www.backyardnature.net/n/15/150614sd.jpg.

Up close it's clear that these are the male stamens poking from the stem. If you snap an inflorescence in two, inside you sometimes find immature anthers embedded in succulent flesh prior to their emergence, as shown at http://www.backyardnature.net/n/15/150614sf.jpg.

Salicornia's succulent inflorescences are segmented. When we read that in the genus Salicornia each segment consists of two 3-flowered groupings embedded in fleshy tissue of the segment above it, and that each of those six flowers per segment normally bears one or two stamens and an ovary with two styles, you wonder where all those parts are. Cutting the fleshy inflorescence lengthwise, or longitudinally, doesn't show much more, just an occasional anther preparing to emerge into the outer world. Pictures on the Internet show inflorescences with stigmas emerging but I can't find plants with stigmas, and will continue looking.

Some of our plants bear old inflorescences, shown at http://www.backyardnature.net/n/15/150614sb.jpg.

In that picture the center spikes bear mature fruits from which seeds can be shaken, shown at http://www.backyardnature.net/n/15/150614sc.jpg.

Those seeds look irregularly formed but if you know that Salicornias are members of the same family as Spinach plants, the Chenopodiaceae (newly lumped into the Amaranth Family), and you remember what Spinach seeds look like when you sow them in a garden, the seeds' shapes aren't surprising. Despite the seeds' tiny size, they're rich in oils. Experimental trials in the US have been made to harvest them on a large scale as a commercial source of vegetable oil. As oils go, Salicornia seed-oil has a high percentage of protein (35%), is highly polyunsaturated, exhibits a pleasant nut-like flavor, and has texture like olive oil, so you can see why there would be interest in it.

Salicornia bigelovii is a tetraploid, meaning that it has four times the chromosome number of the parent species from which it arose. One way tetraploid species can arise spontaneously in Nature is when during the process of meiosis sex germs are produced in which the chromosomes have failed to be reduced by half, as they should have been. This results in pollen grains or ovules having double the number of chromosomes than normal. When such "diploid" sex germs meet they produce tetraploid offspring of an entirely new species. You might enjoy reviewing Wikipedia's page describing this phenomenon.

Most tetraploid species display novel variations relative to their parental species, which might explain this species' surprisingly fleshy body. The body is so fleshy and salty tasting that I like to nibble on it as I walk the marshes, though I know that in large amounts its saponins can be poisonous.



"Plato and This Newsletter" from the October 3, 2010 Newsletter, at http://www.backyardnature.net/n/p/101003.htm

"The Picnic" from the July 12, 2009 Newsletter, at http://www.backyardnature.net/n/p/090712.htm


Best wishes to all Newsletter readers,


All previous Newsletters are archived at http://www.backyardnature.net/n/.