Henry N. Andrews

A New Species of Sawdonia with Notes on the Origin of Microphylls and Lateral Sporangia

A new species of Sawdonia is described from Middle Devonian rocks of northern New Brunswick. The fossils consist of compressions in which axial emergences and sporangia are well preserved. The emergences vary considerably in size and form and are found on both axes and laterally borne sporangia. The sporangia are about 4 mm in diameter and contain large numbers of spores. The plant differs from the only previously described species, S. ornata, in the nature of the emergences on the axes and their presence on the sporangium wall. We also have more information concerning the spores than is presently available for S ornala. A brief review of other microphyllous plants is included with reference to the evolution of the microphyllous leaf.

Early devonian flora of the trout valley formation of northern maine

Abstract The data on the plant fossils of the Trout Valley Formation of north-central Maine, U.S.A., are summarized. Evidence from lithological correlation, from plant megafossils and paleopalynology suggest a late Early Devonian (Emsian) age for the Formation. Plant megafossils present are several species of Psilophyton, Pertica quadrifaria, Kaulangiophyton akantha, Prototaxites sp., Drepanophycus sp., Taeniocrada sp. and Thursophyton sp. The microfossil assemblage, through poorly preserved, contains Deltoidospora sp., Apiculiretusispora sp., Emphanisporites rotatus, E. annulatus, Clivosisporites cf. C. verrucata, Grandispora sp. and a chitinozoan, Sphaerochitina sp. The ancient landscape is suggested as having been an area a few square miles in extent with modest relief and comparable to a modern brackish or fresh-water marsh. Three other floras, one in Maine, a second in New Brunswick, Canada, and a third along the coast of Gaspe Bay, Quebec, are thought to have been at least partially contemporaneous with the Trout Valley flora.

American coal-ball floras

ConclusionInterest in American coal-ball floras has increased perceptibly in the past few years, and some attempts have been made in this brief review to point out current lines of research and what may be expected during the next decade or two. Two other topics might have been considered, namely, a detailed comparison with the European fossils, and a stratigraphic compilation of the American floras. Such considerations would, I believe, be premature at present. We have many genera and a considerable number of species in common with those found in the European coal balls; it is also evident that there were certain elements in the American scene that did not occur on the other side of the Atlantic. Such a comparative picture is, however, only beginning to crystallize. The tendency to date has been to describe those fossils that are new, especially conspicuous and well preserved, and we are still a long way from the end of this “cream-skimming” stage. With continuation of such studies, which are now in progress in four or five laboratories, and the integration of botanical and geological interests, we should ultimately be able to work out a very interesting picture of the sequence of Upper Carboniferous floras and contribute notably to an understanding of the evolution of certain pteridophytic groups and the early seed plants.

A New American Species of Bowmanites

A well-preserved Bowmanites cone is described from the McLeansboro group (upper Pennsylvanian) of Berryville, Illinois. The fossil is a small homosporous cone, about 3 mm. in diameter, and consists of seventeen whorls of appendages. Each whorl consists of six bracts, above which are borne six pairs of sporangia, each attached at its distal end to a recurved forking sporangiophore. The vascular system of the axis is a small triarch structure. The epidermal cell walls of the bracts are strongly sinuous and those of the sporangia slightly so. The spores are monolete and smooth walled.

A Crossotheca from Northern Illinois

During a collecting trip to the famous nodule-producing strip mines south of Chicago, in April, 1947, a specimen of Crossotheca was obtained which displays both fertile and sterile portions of a frond in organic connection. From a comparison with the American and British fossils assigned to this genus our specimen appears to represent a new species. A good deal of interest has been shown in Crossotheca and supposedly related fossils since it is felt that they are microsporangiate fructifications of certain Pteridosperms. The general problem of the affinities of these fructifications has been considered at length by a number of previous workers and need not be repeated in detail here. About a dozen species of Crossotheca have been described, and while certain of these are imperfectly known with reference to the structure of the synangia, the morphology of the sterile foliage, and the general organization of the frond, it is evident that it was a large and varied genus. Judging from the work of Lesquereux, Kidston, Crookall, and others it seems clearly established that in some species the sterile portion of the fronds was of the Pecopteris type and in others of the Sphenopteris type. It is not possible to make satisfactory comparisons with all of the previously described species since in some instances spore measurements are not given or the sterile pinnules have not been found attached.

A Note on the Nodal Anatomy of Ankyropteris glabra Baxter

Considerable interest has been centered in the Carboniferous genus Ankyropteris since it presents, so far as I am aware, the earliest known instance of axillary branching. A comprehensive understanding of the genus may be gained from the works of Scott (1912), Holden (1930), Read (1938), Baxter (1951) and others cited in these papers. It is the purpose of this note to supplement the description of A. glabra Baxter (1951) with particular reference to the nodal anatomy. The specimen of A. glabra described here was found in the same collection of coal balls from which Baxter obtained the type specimen,the Indiana No. 5 coal about 10 miles north of Booneville, Indiana. This species was delimited from previously described species of Ankyropteris on the basis of the lack of multicellular hairs and the origin of the axillary branch from the stem above the point of departure of the leaf trace. When compared with conceivably related species I believe the difference is actually more clear cut. In A. grayi Scott, for example, the stele is much more angular, the central mixed pith is more conspicuous, and the trace at the point of departure from the stem stele is triangular, being quite in contrast to the more or less round (in transverse section) trace of A. glabra. Similar differences clearly delimit A. glabra from A. corrugata (Holden, 1930). On the basis of the type specimen Baxter pointed out that in A. glabra the petiole (phyllophore) trace departs from the stem before the axillary stele, the latter remaining attached to the stem stele for another centimeter. In contrast to this, in A. grayi a single triangular trace departs from the stem stele and then divides into two, one trace becoming differentiated into the petiole trace and the other into the axillary branch trace. The specimen under consideration consists of a stem about 12 cm. long bearing the basal portion of two petioles and associated branches. The internodal distance is 7 cm., corresponding to that cited for the type specimen. Since the anatomy of the two nodes differs somewhat from each other as well as from the type specimen it may be convenient to consider them separately.

Notes on a Visit to Leningrad and Moscow

DURING the past three years I have received a considerable amount of literature from paleobotanical colleagues in the USSR, particularly from Leningrad and Moscow. Because I planned to spend several months in Europe during the summer of 1958 it seemed an opportune time to try to arrange at least a short side-trip to those two cities. I was motivated by a desire to become personally acquainted with some of the Russian botanists, to have an opportunity to see some of their collections, laboratories and working conditions in general, and finally, by the usual curiosity about the country itself. My visit of ten days was so short a time that I could expect to learn only a little. Nevertheless, I have never received so much education in a similar period and my purpose in submitting these brief notes is twofold: to pass along some of my interesting experiences and to encourage other American botanists to visit the USSR. My brief experience may be taken for whatever it is worth, but I am certain that a greater exchange of botanists between the USA and USSR can have only beneficial results.

A Fossil Araucarian Wood Fro Western Wyoming

A few years ago the senior author made a collection of silicified woods from the Gros Ventre Canyon in western Wyoming. We were attracted to the region partly by some petrified log fragments on display outside the Jenny Lake Post Office, which were said to have been collected in the canyon, and partly by a landslide that presents a conspicuous scar on the lower end of the canyon, a landmark readily seen from the vicinity of Teton Park. Although two visits to the slide area failed to reveal anything of paleobotanical interest, certain regions farther up the canyon proved more productive. Approximately twelve miles up the road there is a second and considerably older slide now partially concealed by a fairly heavy vegetation. When this older landslide occurred the Gros Ventre Canyon was blocked and a lake formed in Cole Hollow. At the time of our 1936 visit a petrified trunk some three feet in diameter was exposed approximately 200 yards from the south bank of the river. The slide area was subsequently followed up to its apparent origin, a point about one mile from the river (Mt. Leidy quadrangle, R 112 W, T 42 N). There, a small badlands area, some few acres in extent and light gray color, is quite prominent when viewed from the opposite side of the valley. Sections of silicified trunks and small twigs are comparatively abundant in the gullies, weathering out of rocks of Cretaceous age. A more precise determination of the horizon is not possible at present, since neither the stratigraphy nor paleontology of the region has been studied in detail. Very small-scale coal-mining operations have been carried out on the opposite side of the river, likewise in Cretaceous strata. A seam some four feet thick outcrops about one-half mile north of the river and has been exploited in the past. The seam includes a number of bands of sandy clay some of which contain fern and dicot