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N I923 Drs Krausel and Weyland published a paper on the lDevonian Flora of the neighbourhood of Elberfeld1. This work, though containing much of interest, was to some extent a preliminary notice; since then important new researches have been carried out, and the authors' second paper, published this summer2, is the most considerable contribution to Devonian palaeobotany since the Rhynie discoveries. It is on this second paper that the following remarks are based. The specimens came from several localities near Elberfeld. Use was made of various public and private collections especially those of Herr Piedboeuf, who gave much help. The new finds seem to have been chiefly made in the quarry at Kirberg. The horizon is that of the "Honseler Schichten," belonging to the lowest division of the upper Middle Devonian. It is a fortunate circumstance that the plant remains, while showing the external habit, are often partly petrified, allowing of anatomical investigation. Owing to the nature of this petrification no thin sections could be made; polished surfaces were therefore examined, in reflected light, with good results. Five plants are described. Others still remain to be investigated. The plants dealt with are: Asteroxylon elberfeldense n. sp., Aneurophyion germanicum K. and W., Hyenia elegans n. sp., Calamophyion primaevum n. gen. et sp., Cladoxylon scoparium n. sp. The Asteroxylon is of great interest, for comparison with the now well-known Rhynie species. Branching, naked axes, formerly referred to Hostiimella, are extremely common in the deposit. The ends of the shoots are sometimes circinate. In two cases a sporangium was found terminating a branch. It is now shown that these "Hostimella" branches pass over below into spiny stems, of the Psilophy5on type. Still lower down, the thorny axes are continuous with stems bearing

Asteroxylon Mackiei was a plant of more complicated organisation and larger size than either Rhynia or Hornea, which have been described from the silicified peat-bed at Rhynie in the two preceding papers of this series. The generic name refers to the stellate outline of the xylem of the stem as seen in cross section, while the specific name commemorates the original discovery of the plant remains by Dr Mackie.

Selaginella harrisiana ap. nov. is described from the Permian (Kungurian) Upper Coal Measures at Victoria Pass, N.S.W. It resembles Selaginella selaginoides in its leafy parts but has a long leafless rhizome recalling Asteroxylon. The present evidence suggests that the herbaceous and arborescent ly copsids are taxonomically remote.

The remarkable growth of paleobotany within recent years is revealed in the expanded body of literature and by the increase in number of languages in which it is written. New techniques are involved in the use of cuticles and the electron microscope. Precambrian rocks, once regarded as essentially without fossils, have been found to contain a variety of micro-organisms, and compounds believed to be decomposition products of chlorophyll have been identified in rocks three billion years old. Some new ideas have developed concerning the morphology and relationships of some of the very old vascular plants. The original reconstruction of Psilophyton embodied more than one plant, and Asteroxylon now appears to be a lycopod. The Hyeniales and Pseudosporochnus belong to the Cladoxylales. Archaeopteris and Callixylon are the foliage and woody trunks of the same plant which has been designated a “progymnosperm”. Seeds now appear to have been recognized in the Upper Devonian, and a considerable number of primitive seeds have lately been found in the Lower Carboniferous calciferous sandstone. Decreased coal mining has curtailed the supply of Carboniferous compressions. In North America outstanding progress has been made in the study of petrified plants in coal balls. Studies of the Glossopteris flora have been extended into Antarctica. Continental drift seems to be the only hypothesis that satisfactorily explains the position of the fragments of ancient Gondwanaland at the present time. Reinvestigations of the inflorescences of Cycadeoidea have shown that the structure of the staminate disc was originally misinterpreted. It is a complex synangium that encircles the gynoecium, rather than being a whorl of pinnate stamens. The occurrence of angiosperm leaves in the Lower Cretaceous of Greenland is questioned. Some investigators now believe that angiosperms originated at high altitudes in the tropics during the Permian Period. Others would derive them from the Glossopteridae during the same period. Fruits and seeds have proved quite useful in accurate determination of Tertiary angiosperms. Petrified woods create special problems in identification and nomenclature.

Summary An investigation of the cuticle of Psilophyton princeps Dawson from the original locality in Canada has revealed the presence of stomata on the epidermis of the stem. This epidermis resembles in a general wily that of the petrified members of the Psilophytales from the Rhynie Chert, but the stomata differ in the presence of cuticular thickenings and the epidermal cells are usually papillate and not ridged. In the numerical distribution of stomata on the stem, Psilophyton agrees with Asteroxylon rather than Rhynia. There is no evidence that the highly cuticularised spines are homologous with the traumatic intumescences of Rhynia, and they differ from the slightly larger and less spine-like leaves of Asteroxylon, with which a closer comparison is possible, in the absence of stomata.

This part of the account of our examination of the plants preserved in the silicified peat-bed of early Old Red Sandstone age found at Rhynie will be devoted to the consideration of a number of general questions concerning the four Vascular Cryptogams which it has yielded.1. In the first place the morphological characters of Rhynia Gwynne-Vaughani, R. major, Hornea, and Asteroxylon will be reviewed and the attempt made to reconstruct the external appearance of these plants as they grew. In relation to this a few additional features of the plants will be described.2. This will lead naturally to a consideration of the general bearings upon plant-morphology of the facts mentioned in this series of papers.

In Part I a general account was given of the silicified peat-bed found at Rhynie, and one vascular plant was described in detail under the name of Rhynia Gwynne-Vaughani. Further study has shown that there are two species of Rhynia which we now distinguish as Rhynia Gwynne-Vaughani and Rhynia major. The account in Part I applies to both these species. Along with them there occurs a plant of similar grade of organisation to Rhynia, though quite distinct from that genus: this we name Hornea Lignieri. Asteroxylon Machiei, on the other hand, which will be described in the next part, was a plant of larger size and much more complex morphology.We are thus now able to establish the existence and main features of four archaic Vascular Cryptogams from the Rhynie bed. In the present paper additional notes on R. Gwynne-Vaughani are given, and R. major and Hornea Lignieri described in detail. In conclusion, the morphological bearings of the facts will be briefly considered.

Asteroxylon mackiei was first described from the Rhynie Chert by Kidston and Lang1, but the nature of its reproductive region has remained uncertain, since the peculiar leafless axes and small pear-shaped sporangia, which they provisionally assigned to the plant, have never been found connected to its leafy stems.