leafy liverwort and its gemmae.
Deep Woods Preserve, Hocking County, Ohio.
December 27, 2008
Along with the much more numerous mosses and the much less numerous hornworts, liverworts are a type of bryophyte. Bryophytes are little plants that are usually described as "non-vascular" because they lack the specialized plumbing --water-carrying xylem and food-carrying phloem --that characterizes all the other true plants. Compared to mosses, most liverworts have more intricate leaves, but by contrast the liverwort spore-producing stage of the life cycle is simpler and more short-lived than the corresponding sporophyte of mosses.
Mixed with mosses on a moist shaded sandstone ledge in a hardwood forest in southern Ohio is a lovely little leafy liverwort Diplophyllum apiculatum (family Scapaniaceae). Somewhat flattened, it has deeply two-lobed leaves that spread out in two rows on opposite sides of a horizontal stem, and these leaves are "conduplicate," i,.e, the rear edge is folded underneath and extends forward.
Diplophyllum apiculatum, approx. 25X microscope view (original).
Diplophyllum apiculatum, approx. 40X microscope view (original)
Diplophyllum, like many plants, can reproduce in two ways: (1) sexually through an intricate process involving spores and eggs and sperm, and (2) asexually, wherein a plant produces exact copies of itself. The asexual reproductive structures of this liverwort are small 1-2 celled "gemmae" produced abundantly at the tips of many branches. Diplophyllum gemmae are distinctively angular.
Diplophyllum apiculatum gemmae, approx. 400X microscope view (original)
Air freshener is not very precise botanically!
This air freshener says on it that it's a "Royal Pine" freshener. But the conifer pictured on the package has single (not bundled) needles. That feature, together with the pendant (drooping) cones indicates the picture is actually a spruce (genus Picea, family Pinaceae). Moreover, spruce generally smells like cat urine, and pine is not a whole lot better, being faintly turpentine-like. The best-smelling conifer is fir (genus Abies, also in the Pinaceae).
Air freshener with an identity crisis!
(Gas station shop in Marion, Ohio.)
Butternut Walnut Hazelnut
Deep Woods Preserve, Hocking County, OH
December 27, 2008
Butternut (Juglans cinerea, family Juglandaceae) is a beloved hardwood tree that is becoming scarce throughout much of its range because of a fungus disease that causes twig and stem cankers that eventually kill the tree. Sometimes called "white walnut," butternut is a close relative of black walnut, which is very common. In the winter, trees can be identified by their twigs. Juglans twigs in general are distinctively stout, with a prominent terminal bud and monkey-face leaf scars.Twigs of two Juglans species. Left: butternut (J. cinerea). Right: black walnut (J. nigra).
How can you tell the two species apart by their twigs? Two main ways: (1) the terminal bud of butterut is proportionally longer than that of black walnut, and (2) the upper edge of the butternut leaf scar has a velvety moustache-like ridge that is lacking on black walnut.
Another intriguing Juglans twig feature involves the pith (the softer cylinder in the center of the twig,composed of a different cell type than the woody xylem that comprises most of the twig). After making a longitudinal section with a razor blade, you can see the pith is chambered, i.e., hollow with cross-partitions.
Contrary to what you might expect knowing that butternut wood is much lighter colored than black walnut, butternut pith is substantially darker!
Chambered pith of two Juglans species. Left: butternut (J. cinerea). Right: black walnut (J. nigra).
Another woody plant that is distinctive in the winter, if by chance it has some persistent fruits, is American hazel (Corylus americana, family Corylaceae). The typically paired nuts look like big-lipped talking heads facing away from each other, maybe.
Fruits of American hazel. Deep Woods Preserve, Hocking County, OH. Desember 27, 2008.
Honey-locust et al. addition to "Dirty Trees"
Norway maple addition to "Tree Flowers"
(originally published in OBELISK, the newsletter of the
Ohio Moss and Lichen Association )
Some of the most intriguing mosses are like pixies: small, cute, and appearing for a short time only. Ephemeral mosses tend to appear on disturbed open ground. Farm fields and moist spots in paths through open woods are good places to look for them. You need to get on your knees and keep the hand lens busy. Most or all of them are acrocarps, also called “cushion mosses,” i.e., mosses that consist of separate upright stems bearing sporophytes at their tips. In a manner analogous to the woodland spring wildflowers that burst forth during April before leaf-out shades them, ephemeral mosses generally occur when the potentially overtopping wildflowers or crop plants are absent.
many species, their timing of occurrence is either
during spring or fall, but not both seasons. One of the most commonly
species, somewhat larger than the other plants mentioned in this
the “urn moss,” Physcomitrium
(family Funariaceae). It is a spring ephemeral with distinctive broad
clustered at the base of the plant, and abundantly produced sporophytes
with a long seta (stalk) bearing a capsule shaped like a
child’s toy top. P. pyriforme
is known from 51 of
Physcomitrium pyriforme. Hocking County. May 7, 2006
Interestingly, there is another plant, smaller but otherwise nearly identical in appearance that occurs in the same habitats (fallow fields, roadside ditches, etc.) as does Physcomitrium but it most often fruits in fall, and is only rarely seen in spring. This is Tortula (formerly Pottia) truncata (family Pottiaceae). While the Ohio Moss Atlas shows only five county records for this species, it is probably much more common, at least in regions with calcareous soils. The apparent rareness is probably an illusion due not to actual scarcity, but rather because naturalists don’t tend to crawl around on the ground as much in November as they do in May.
Pottia truncata. Marion County. November 5, 2007.
mosses have sporophytes with setae that are
moderately or very short. Bruchia
flexuosa, (family Bruchiaceae) is an elegant spring-fruiting
from 9 counties. The capsules, which are elevated slightly above the
leaves, have a broadly tapered neck that contributes to an unusual
shape reminiscent of a weather balloon. Like many ephemerals, Bruchia capsules
lack the lid-like operculum
that most mosses have, and thus the capsule ruptures irregularly to
Bruchia flexuosa. Marion County. May 9, 2008
Several other ephemeral mosses have setae so short they are barely discernable, and so the capsules are immersed in the uppermost leaves. One such species that is fairly robust (for an ephemeral) grows in dense patches: Astomum muhlenbergianum (family Pottiaceae). It is one of our few mosses with involute (upward-curling) leaf margins. The species has been reported from 12 Ohio counties.
Astomum muhlenbergianum. Marion County. March 27, 2008
A final example, among the tiniest of the tiny, is the aptly named genus Ephemerum (family Ephemeraceae), of which E. crassinervium is our most common species. It occurs, spring or fall, as scattered plants amidst a thin but sprawling alga-like growth stage called the protonema, and is known from only 8 counties in the State.
Ephemerum crassinerveum. Marion County. November 11, 2007.
Some other ephemeral genera to look for are Phascum (Pottiaceae), Aphanorregma (Funariaceae), Pleuridium (Ditricaceae), and Micromitrium (a genus very similar to Ephemerum, also in the Ephemeraceae). The “pixies” are fun to hunt, and seem to be a strikingly under-reported component of our moss flora. By looking closely at the ground at odd times of the year in places which seem quite unexceptional, it’s possible to meet some truly remarkable plants.
We took a trip to the sea, but we got there late!
(400 million years late)
Caesar Creek Lake State Park, Warren County, Ohio
During the upper Ordovician Period of the Paleozoic Era, southwestern Ohio was covered by a shallow sea. Limestones and shales from this area and adjacent portions of Indiana and Kentucky are extraordinarily rich in fossils. One of the best places to see them is at the spillway for the Caesar Creek dam. During the late 1970's the U.S. Army Corps of Engineers built the dam to impound the nearly 3000-acre lake. They also excavated a spillway to serve as a "safety valve" so that, in case there were ever a severe flood that could potentially overtop the dam, damaging the damn dam (sorry) in the process, the water would be shunted around it. I'm not sure whether there's ever actually been a flood that high, unless you accept creationist explanations for why we see the remains of sea creatures in places like this. Here's Google Maps view of the area (if it hasn't shown up, "refresh" your browser):
("refresh" browser if the map doesn't appear)
Aerial view of Caesar Creek Lake, dam and spillway.
(The spillway is at the south, bisected by Clarksville Road.)
The Corps graciously allows fossil collecting here, provided that you pick up a free permit and obey a few simple rules. The area is marked by an interpretive sign.
Caesar Creek Lake spillway interpretive sign.
Spillway detail, interpretive sign.
The spillway is about 2700 feet long, 500 feet wide, and it exposes, in total, approximately 70 feet of shale sedimentary rock strata. Fossils are likely to be found anywhere in the spillway.
Spillway panorama, taken at west end, facing east-northeast. November 2, 2008.
The early Paleozoic was a time when shelly marine creatures ruled the world. There are representatives of the same phyla as contemporary animals, but with strikingly different groups predominating. The most numerous shells are those of brachiopods (lamp shells). Superficially, they resemble clams (phylum Mollusca) but internally they are very different animals.
Brachiopod fossils. Caesar Creek, Novemner 2, 2008.
Although far less common than the brachiopods, there were indeed molluscs in the Ordovician. One group is gastropods (snails). Here are two specimens.
Fossil gastropod molluscs at Caesar Creek. November 2, 2008.
Another, more striking, mollusc was the cephalopod. This was a member of the same molluscan class as the squid and octopus of today, but it had an external shell. It must have looked like an octopus with a dunce cap. In his masterpiece "The Cartoon History of the Universe," imaginative cartoonist Larry Gonick depicted a cephalopod, which he calls a "shell-squid" in the following lighthearted manner.
Cephalopods were chambered internally. This partioning is reflected in some of the fossils, as shown below.
Fossil cephalopod mollusc, Caesar Creek. November 2, 2008.
Corals belong to an animal phylum that is well represented both in the Paleozoic seas and the present day. Along with jellyfish (nowadays more correctly termed "sea jellies" because they are not fish), sea anenomes and hydra, these animals are all predaceous carnivores who paralyze their prey using tiny toxin-tipped stinging devices (cnidocytes). Coral animals are individually small, and live in colonies within a stony (calcareous) matrix that they secrete. One of the most conspicuous and intriguing Ordovician corals is the horn coral, belonging to an extinct order.
Horn coral fossils. Caesar Creek. November 2, 2008.
An expecially common organism back then, similar to corals insofar as they are minute colonial animals that construct limey apartment houses, were the bryozoans (phylum Bryozoa). Bryozoans still exist today, but they are much less abundant now than they were back then.
Fossil bryozoan. Caesar Creek. November 2, 2008.
The phyum Echinodermata includes starfish (nowadays more correctly termed "sea stars" because they are not fish), sea urchins (which are not urchins), sea lilies (which are not lilies), and sea cucumbers (which, even though you can buy them to eat at the local Asian grocery store, are not cucumbers). Echinoderms have spiny skin and, as adults, 5-part radial symmetry. Crinoids were common in the Ordovician seas. Looking like flowers, a crinoids was anatomically like a starfish on a stalk. Fossil-hunters are rarely lucky enough to see the flowery tops, but screw-like crinoid stems are fairly frequent.
Crinoid fossils at Caesar Creek. November 2, 2008.
The Caesar Creek Visitor's Center, where you pick up the collecting permit, has a nice scientifically oriented gift shop that sells nature guides and a "Fossils of Caesar Creek" T-shirt.
Happy fossil hunters at Caesar Creek. November 2, 2008.