PLANT FRAGMENTS FROM DEVONIAN BEDS IN CENTRAL YUNNAN, CHINA

B y J. H su

(With 5 Plates, one Map and 5 Text-figures)

A bstra ct The paper describes 45 specimens of plants collected from Devonian beds at several localities in the districts Lihsien, Kunming, Ch’iiching and Luch’iian of Central Yunnan, China. It is unfortunate that most of the fossils are -too frag: mentary to furnish specific identifications. They are preserved as casts, moulds and incrustations in various kinds o f sandstones and shales. Specimens referable to Protolepidodendron scharyanum Krejci are the commonest in this collection. Tceniocrada cf. dubia Kr. and W., Asteroxylon cf. elberfeldense. Kr. and W., and cf. Zosterophyllum are o f great Interest and are here recorded for the first time from Asia. Other fossils are provisionally referred to Drepanophycus spinceformis Go ppert, Protopteridium minutum Halle, Barrcmdeina, Hostimella, Protolepidodendron 1 arborescens Sze, Leptophloeum australe McCoy, and Heleniella Theodori Zalessky. Several fragments show the . decorticated, stems of some lepidophytic plants preserved in Jfaoma-state. A new species, ? Sublepidodendron sinensis is described. Attempts at cuticle preparations have been made, but do not yield good results. The-axis of Tceniocrada cf. dubia has revealed a cutinized epidermis, but hardly any details are visible; an interesting fact is that the vascular bundle contains tracheids with bordered pits. It is obvious that the flpra represented at these localities in the four districts in question is of Devonian aspect, and at least in each of the first' three districts it is of Lower to Middle Devonian affinities. Although1 the work is of much interest it is fair from satisfactory owing to the frfl.gmfint.ary nature of the material. However, it strongly suggests a promising field for further, investigations at these localities.

I. Introduction Previous records of Devonian plants in Asia Our knowledge of the Devonian flora in Asia is restricted to a few papers. Probably the first paper dealing with the Devonian plants of Asia •was made by Colani (1919). She recorded some specimens from Ta-nong-pou in Southern Yunnan, China, and Sui-mo-koa in Northern Tongking, Indochina. Unfortunately her specimens are too fragment­ ary to be identified.1 In 1927 Professor Halle, reported Arthrostigma' gracile Dawson from a Lower Devonian bed. at Chanyi. in Eastern Yunnan, China, and in 1936 he again described some interesting specimens of Protolepido-< dendron scharyanum Krejci,-Pro topteridiumjninutum Halle and Drepdnb- phycus spinceformis Goeppert l(= Arthrostigma 'gracile Dawson) 'from the district Ch’uching. 24 340 J. H SV

Kryshtofovicli in. 1927 recorded Psilophyton sp., Sporogonites exuberans Halle and Dawsonites arcuatus Halle from Turkestan, Central Asia. .Later on Zalessky (1936) described Psilophyton'princeps from Ufal (Stockmans, 1940, p. 9); Dr. H. C. Sze (1936) reported a Devonian plant, Protolepidodendron ? arborescens Sze from Tiaomachien in Central Hunan. In 1941 he again reported Psilophyton princeps Dawson and ? Hostimella sp. from Chaotung in Eastern Yunnan. From the above summary of the literature it would seem that the Devonian flora of Asia is very poor as compared with that of Europe; but this may- be due only to the fact that very little work has yet been devoted’ to it. I was tempted to take up the present work in the hope of extending our meagre knowledge o.f the subject by describing some collections from China. Occurrence o f the present specimens In 1943 I receiyed 45 specimens of plants collected from Devonian' beds at several localities in the districts'of Lihsien, Kunming, Ch’iiching and Luch’iian of Central and Eastern Yunnan, China (see map). These fossils, like most Devonian material, are also fragmentary; they are preserved as casts, moulds, and incrustations in various . kinds of sandstones and shales. Most of them sire represented only by naked axes of vascular plants but some possess leaves, spines 'or leaf-cushions. The specimens from the district of Lihsien were collected by Professor Y. C. Sun and Mr. C. V. Ku o f the National South-Western Associated University, Kunming, from several localities in the P’oshi region. The fossils labelled T8, Tl5, Tl8f and T1$J. are from a series' of Devonian beds at Itate and Ludouchuan. The different horizons are designated T8’ Tl5l etc. respectively. According to the opinion of the collectors, the bed Tg may be of Upper Devonian and the rest are Middle Devonian (Ku, unpublished paper). The specimens labelled Rs, WH2, CD zp_d, PSW5, PSW8, and PWVia were collected from some Middle Devonian beds at other' localities in P’oshi. The specimens from Kunming were collected by Mr.. P. S. T’shong of the National University of Yunnan from some Middle Devonian beds at Chintien, about 12 km. east of the city of Kunming. Specimens from the district Ch’iiching were collected by Professor Y; C. Sun from beds of Middle or Lower Devonian age at several loca­ lities. There is one specimen from a Devonian bed in Luch’iian. Acknowledgment This work was carried out at Lucknow during the years 1944-46 under the guidance of Professor B. Salmi, F.R.S.; to whom I am extremely grateful. I owe-, valuable criticisms and .suggestions to Professor T. G. Halle of Stockholm and Professor C. A. Arnold of Ann Arbor (Michigan). I wish to express my thanks to Professor DEVONIAN PLANTS FROM CENTRAL YUNNAN 341

Y. C. Sun, Messrs. C. V. Ku, and P. S. T’shong for kindly collecting the specimens for me on my request. I am also grateful to the University of Lucknow for granting me a research scholarship during my stay in India.

II. D escription A . Specim ens from P’oshi in the district of Lihsien Some specimens were collected by Professor Y. C. Sun of the National Peking University and Messrs. C. V. Ku, T. S. Han, and L. G. Hu of the Geological Survey of Yunnan from several localities in P’oshi. Most of them are too fragmentary and poorly preserved to be identified. Under careful examination and comparison, the following fossils were determined • Protolepidodendron scharyanum Krejci, Taniocrada cf. dubia Kr. and W., cf. Drepanophycus spincs- formis Goeppert, and cf. Asteroxylon elberfeldense Kr. and W. A somewhat spinous axis probably recalls the thorny branch of Psilo­ phyton princeps Dawson. Some ribbed axes are referred to the stem of Protopteridium minutum. Several casts and incrustations represent the axes of some unknown plants with branches, spines and long ridged.or short rhombic leaf-cushions. v 1. Protolepidodendron scharyanum Krejci (PI. I, Figs. la, 2-5; PI. Ill, Figs. 25-26; Text-fig. 1) Five specimens referable to Protolepidodendron scharyanum were obtained from four different beds exposed in the P’oshi region,' which shows that this species was probably a common plant at the time in these localities. The shoots of this plant are covered with leaves. Each leaf con­ sists of a large decurrent leaf base, generally of an oblong shape, from which arises an elongated limb tapering rather rapidly to a slender elongated point. In well preserved leaves this point is seen to be continued into a peculiar delicate minute forked apex (PI. I, Figs. 3-5). When the forked apex is not clearly seen or is not preserved the1 leaf has tthe appearance of a spine. The decurrent leaf base forms a well marked cushion on which the lower end of the free limb is sometimes seen marked by two converging lines.. The degree of decortication and the quality of preservation make it difficult to define the character of the leaf cushions. But generally they have a narrowly oblong outline. In places especially thicker parts of the axis, the leaf limbs appear to have dropped off and the outlines of the cushions are more clearly exposed (PI. I, Figs. la, 5; PI. Ill, Figs. 25-26). They are generally rather crowded together, concealing from view the' entire or almost the entire surface of the stem. . The arrangement of the leaves is not always very clearly shown. The main question at issue is whether the arrangement is spiral or whorled. This question being of some little importance from, the point 24a J. HSi)

Map showing the localities from which the material here described was collected.

of view of the affinities of the genus,'we shall describe this feature in some detail. On the’ narrowest axis*the leaves appear to be spirally placed with their bases contiguous and covering the whole surface of £he stem (PL I, Figs. 3, 5). In the thicker proximal.parts o f the same shoots some leaf cushions are seen separated from each other by DEVONIAN PLANTS FROM CENTRAL YUNNAN 343 narrow strips of the stem (PI. I, Fig. la; PI III, Fig. 25), but the arrange­ ment is still clearly a spiral one. Still thicker stems show the cushions clearly separated from each other and (at least in one specimen, see PI. I, Fig.. la) there is a vague suggestion of something like a verticillate arrangement, though the verticils (if such they are) are placed obliquely across the stem—a fact which may indicate that here also the arrange­ ment, may after all be a spiral one. Figs. 2 and 3 of PI. I show two fairly well-preserved young leafy shoots, 2 • 1 cm. and 1 -2 cm. long. PI. I, Figs. 4, 5 show another young leafy shoot, with both ends broken, which is about 1 -5 cm. long. In these slender shoots, the axes are only 0 -5-1 mm. thick and are preserved as thin flattened incrustations in a grey sandstone of the bed Tisr (p. 12). This carbonised crust is raised into a series of ridges which represent the decurrent bases o f the crowded spirally placed leaves and cover the entire surface of the stem. At a first glance the leaves look like spines, but under careful examination they are seen to be slender, more or less flexible blades bent in various directions. In a few of the leaves the bifid apex so characteristic of the genus Protolepido- dendron is also fairly clearly preserved, leaving little doubt as to the affinities of the plant {cf Krausel and Weyland, 1932, p. 391, Fig.. 1). In the. older shoots which are 4-7 mm. thick (PI. I, Fig. la; PI. Ill, Figs. 25a, 25b and 26), the leaf cushions are shorter and fusiform. In passing across the axis four to six leaf cushions may bej met with, and between them narrow strips of the stem surface are exposed. It is a pity that none of these older stems have any of the leaf limbs pre­ served, but a comparison with Halle’s PL 2, Fig. 2 (1926) strongly supports the reference to Protolepidodendron scharyanum. The fragment shown in PI. I, Fig. 1 a represents the thin flattened incrustation of a shoot in a calcareous sandstone PSW8 (p. 12)5- The leaf cushions • are represented by narrowly oblong depressions. The arrangement varies between spiral and verticillate. The fragments shown in PI. Ill, Figs. 25a, b represent the internal casts of shoots, preserved in a grey sandstone PSWs (p. 12). They are 6 mm. in breadth. The leaf cushions are elevated lenticular in shape and about 2-4 mm. long. Their arrangement is also more or less between spiral and verticillate. In passing across seven to eight leaf cushions may be met with, and between them narrow strips of the stem surface are also exposed. In the specimen shown in PL III, Fig. 26 also, the scars, of leaf cushions, although poorly preserved, are very similar to those shown in Halle’s PI. 2, Fig. 7 (1936), except that in my specimen the leaf limbs are not, preserved. It is found in a coarse yellow sandstone bed T15 (p. 12) in which any well preserved fossil impressions could hardly be expected. The leaf scars are represented by obovate depressions, with their upper end somewhat flattened or even a little concave (Text-fig. 1). The contour of the lower end is not clear. Two faint longitudinal lines arise.from the upper end, dividing the leaf scar into .three more or less equal portions and'disappear just after passing the middle of 344 J. HSU

the scar. Such scars are also arranged spirally, and in passing across the stem about 7-8 of them may be met with (compare Halle’s PL 2 Fig. 7).

/

Text-fig. 1. Protolepidodendron scharyanun Krejci. Leaf scars.

The fragments shown in Pl. V, Fig. 49 from Ch’iiching and in PL IV, Fig. 42c from Kunming again present a very close resemblance with Halle’s PI. 2, Fig. 2 (1936).

1 2. Taniocrada cf. dubia Kr. and W. (Pl. I, Fig. 11; Pl. II, Fig. 20-24; Text-figs. 2a-c) Fig. 11 of Pl. I and Figs. 20-25 of Pl. II show some yellowish ribbon-like plant fragments resembling very closely the specimens described as Taniocrada dubia (Krausel and Weyland, 1930,p. 42, Pl., 9,sFig. 4; Stockmans, 1940, pp. 46-47. Pl. 1, Fig. 7; Pl. 9, Figs. 4-4a) and almost border on identity. They were found in a grey sand­ stone bed Tl8c, one of the lower beds of the strata of Itate «.na Ludonduan (p. 12). They are preserved in the form o f thin flattened incrustations up to 1 mm. in thickness, with a distinct slender straight carbonised central strand. It. appears to me that in T. cf. dubia the stem was not a flattened ribbon as suggested by Krausel and Weyland (1930, pp. 36-38) in the case of T. decheniana, but more or less cylindrical.* The fragments measure about 1 *2-1 -6 cm. broad and the central strand about 1 -4-1 -8 mm. wide. Usually the latter is displaced a little from its, median position. The slender lateral branch (PL I, Fig. 11) arises at an acute angle with the main axis below the point of forking. . The surface of the fragments is not quite 'smooth, but shows a number of short longitudinally placed groove-like scars^ca. 0-6-1 mm. long (Pl. II, Fig. 22) which appear to indicate that the stem was covered with elongated spine-like emergences. The distribution of these spines

* I am indebted to Professor Halle for the suggestion that even in T. decheniana the . stem may have been cylindrical and not ribbon-like. DEVONIAN PLANTS FROM CENTRAL YUNNAN 345 is irregular and is . not affected by the pressure o f the mid-rib. This fact supports the idea that v they mark the impressions of narrow, rathe stiff spine-like emergences and goes distinctly against any idea o f a submerged habit for T. dubia such as was suggested in the case of T. decheniana by Krausel and Weyland (1930, pp. 36-37, Fig. 25 of p. 36). The scars are too numerous and too clearly preserved to be mistaken for accidents of preservation. At the same time a transfer preparation made by Walton’s method (1930), shows a membrane which must be a cuticle (because it was insoluble in HF, Schulze’s solu­ tion and dilute KOH), but unfortunately no cell structures are preserved. The central carbonised strand was macerated in. Schulze’s fluid for two days and again treated with 10% KOH for 5 minutes. Some fragments of tracheids were obtained. They are 15-22/a in width, with uniseriate round pits which are sometimes more or less clearly bordered and show the elliptical pores ca.. 4 (x long on the two

sides of the wall crossing at an angle (PI. II, Figs. 23-24 and Text-figs. 2a-2c). The borders are not well preserved, being shown only as a blackish thick rim round the aperture (Pl. II, Figs. 23-24). Some­ times the pits are elliptical and more or less extended horizontally across the tracheid wall, give'a scalariform appearance (Text-fig. 2a). The occurrence o f bordered pits is rather interesting, for it was hardly expected in such a slender vascular strand. To some slight extent it supports the view that T. dubia was not a submerged aquatic. As we know, only scalariform and simply pitted tracheids had so far been found in the central strand of T. decheniana (Kr. and W. 1930 p. 4, Fig. 5). . From the stratigraphical point of view also these specimens are very interesting. All the specimens named under the genus Tceniocrada are recorded only from the Lower Devonian (Krausel and Weyland^ 346 / . HSU 1930; Steinmann and Elberskirch, 1928; Stockmans, 1940; Croft and Lang, 1942; Corsin, 1933; andDorf and Cooper, 1943).* The speci­ mens previously described as T. dubia were also found only in the Loyrer Devonian of Germany (Krausel and Weyland, 1930) and Belgium (Stockmans, 1940). So that, judging from this kind of plant, the lower beds of the strata o f Itate and Ludonduan would, probably be Late Lower Devonian.

3. cf. Drepanophycus spinceformis Goepp. (Pl. I, Figs. lb, 6-8) There are four specimens, all fragmentary and poorly preserved which are doubtfully referred to Drepanophycus spinceformis Goepp. They will be described individually, as their specific identity is not at all clear. (a) The best fragment (Pl. I, Fig. 6) is a short axis about 1 cm- long, bearing 4 or 5. spines apparently in a spiral manner. The longest spine is about 3 mm. long and nearly half as broad at the base. This is preserved in a thin, flattened incrustation in a blackish grey shale PWVia (p. 12). After the surface of the specimen was treated with Schulze’s solu­ tion for one day on the rock and 2% KOH was applied for 1 minute most parts of tjie carbonised surface of the branch were bleached and some thin blackish lines were brought out prominently in both the axis and the spines (shown by an arrow in-Fig. 6). In the spines these lines are medially situated running from the tip to the base. Unfortu­ nately this is the. only specimen which I possess; otherwise I would have tried to study whether the black lines are vascular or not The spines may be compared with those of Drepanophycus spinceformis (Halle, 1936, Pl. 1, Fig. 1-2; Lang, 1932, Pl. 1, Figs. 1-3). (b) Pl. I.' Fig. 8 also shows a piece of a carbonised spinous young branch, preserved in a thin flattened incrustation in a grey sandstone PSW5 (p. 12). The spines are rather minute, resembling rose prickles. (c) Pl. I, Fig. 7 shows another young branch of the same type preserved in a. similar condition in a grev sandstone o f the Tl9c bed (p. 12) which is the lowermost bed o f the Itate and -Ludonduan Devonian Series. But (b) and (c) appear very likely to be the young branches of Drepanophycus spinaeformis comparable with specimens figured by Krausel and Weyland (1935, p. 183, Fig. 7). (d) PI. I, ^ig. 1 b shows a comparatively sjender stem bearing crowded spirally arranged leaves. It appears very likely, to be a young branch o f Drepanophycus spinceformis comparable with the specimen

* I am indebted to Professor C. A. Arnold for correcting this stetement: he has • kindly informed me that Tceniocrada was originally described from Upper Devonian beds (see New York State Museum Report, Vol. 55, 1901). DEVONIAN PLANTS FROM CENTRAL YUNNAN 347 figured by Croft and Lang (1942, PL 9, Fig. 4). Our specimen is pre­ served in a thin, flattened incrustation in a calcareous sandstone PSWa (P. 12). 4. A spinous branch (Pl. I, Fig. 9) This is a poorly preserved specimen of a branch about 5 mm. broad preserved in an incrustation in a grey sandstone PSWs (p. 12). Some minute carbonised spots are seen scattered on the surface which seem at first sight to be impressed spines. They measure up to about 1 mm. but generally are short, bar-shaped, about 0-5 mm. long and 0*3-0-4 mm. wide, and arranged spirally along the axis. These spots are situated about 1 -2 mm. apart from each other left and right, but 2 mm. apart from those above and below. Some spots appear only like small black depressions that give'me an impression indicating that the appendages were somewhat rigid. To some extent the fossil recalls a branch of Psilophyton princeps Dawson but no comparison is possible because the spine-like bodies are arranged spirally on the axis in a regular manner which gives an impression that they may be leaves whereas the spines in Psilophyton are generally regarded as emergences. 5. Some ribbed axes (cf. Protopteridium minutum Halle) (PL III, Figs. 32-33,'34-35) Fragments of this kind are common in the lower beds of the Itate and Ludonduan Devonian series, but they are all too fragmentary to be identified. Most of them were found in the bed Tl8(. (p. 12). Some slender axes shown in PI. Ill, Figs. 32, 336 and 35 are marked by 4-7 prominent ribs on the exposed surfaces. The stoutest one measures about 7 mm. Another specimen found in the grey sandstone PWV19 (p. 12) (Fig. 34) is rather broader, measuring about 1 cm. in width. Some similar kind of axes were also found in Ch’uching (Pl. 5, Figs. 48, 53) which may belong to the same plant. Although the axis of Protopteridium minutum Halle was not de­ scribed as .ribbed, yet judging from the figures given by Halle (1936, Pl. 4, Figs. 1-2, 6-7), some axes.are distinctly marked by four or more ribs. Were the axes of Protopteridium minutum usually ribbed or were these ribs only seen on the decorticated stem? It is very difficult to judge without seeing the original specimens of Professor Halle. The specimens found in the bed T1?(- agree very closely with Protopteridium minutum Halle. But the identification should await the discovery of more reliable specimens. 6. cf. Asteroxylon elberfeldense Kr. and W. (PL II, Figs. 15-18 and Text-figs. 3 and 4) Pl. II, Fig. 15a shows a kind of plant with dichotomous branches.. It appears to be very common in the bed. The longest fragment 348 / . HSU measures about 8 cm. (Pl. II, Fig. 15a; Text-fig. 3). The axis is slender m a fairly uniform thickness of about 1 -5 mm. Most of the fragments are decorticated and show no trace of, leaves on the- surface, but

Text-fig. 3. cf. Asteroxylon elberfeldense Kr. and W. in a fe.w places some small leaves (?) are seen alternately and loosely arranged (Pl. II, Fig. 16). The shape is not clear; in a side view they are -at least 2 mm. in length. In a few places tr'aces of a central strand are seen running longitudinally through the stem (Pl. II, Fig. 16). On' the same piece of rock there is a hooked apex of a branch (Pl. H, Figs. 15c and 17 and Text-fig. 4). Judging from the nature and colour of the specimen, it seems without much doubt to be related to the dichotonfous branch.

Text-fig. 4. cf. Asteroxylon elberfeldense Kr. and W. These fossils resemble closely, the specimens from Germany de­ scribed as Hostimella hostimensis Pot. et Bern, by Weyland (1925, pp. 40-41, Figs 1-2) and Asteroxylon elberfeldense by Krausel and Weyland (1926, pp. 118-126, Pl. 3, Figs. 2-6; Pl. 4, Fig. 6; Pl. 5, Fig. 6). Krausel and Weyland state (1926, pp. 123-24) that Hostimella hostimensis represents the young branches of Asteroxylon elberfeldense. DEVONIAN PLANTS FROM CENTRAL YUNNAN 349

At Pl. II, Figs. 15& and 18 there is a short axis in which a part of the external surface is preserved and is seen to be.densely covered.with scale-like” appressed leaves; while the more distal part of the same axis shows traces of a central vascular bundle (Pl. II, Fig.- 16). These facts, combined with the hooked apex just mentioned, seem to_ support the view that our plant is at any rate closely related to, if not identical with, Asteroxylon elberfeldense Kr. and W. 7. Hostimella-like dichotomous axes (Pl. Ill, Figs. 28, 29). Pl. Ill, Figs. 28-29 show some dichotomous branches, which are preserved as an incrustation • in a yellowish grey sandstone, labelled R5 by the collectors. The axes bifurcate repeatedly and have a shining surface with a fine reticulate longitudinal striation. The meshes appear to be elongate with the longer sides parallel to the direction of the axis. Most'probably they represent the epidermal cellular structure of the axis. There is no trace of spine or leaf attached to it. The width of the axis varies from 2 to 6 mm. The affinity is obscure. They may be named as Hostimella sp. but I prefer not to name them because of the imperfect preservation. 8. An axis with short rhombic leaf-cushions (Pl. IV, Fig. .38, 39) The rhombic outlines of the leaf cushions are preserved in a calca­ reous sandstone PSW8 as a thin carbonised crust. The rhombic areas measure about 1 mm. long and 2 mm. wide. Near the middle of some of the rhombic areas a short carbonised line is also seen but it is impossible to say what this represents. This tiny fragment is being figured here only because of the rhombic form of the leaf cushions, which vaguely suggests that the fossil may.be a lycopod,'possibly related to Lepto- phlceum australe McCoy (Walton, 1926, Fig. 1) which is known from the Middle Devonian to the Lower Carboniferous (Seward, 1910, p. 178; 1941, p. 144). 9. Axes with superposed long leaf cushions. (a) Type 1 (PL III, Fig. 31).—An internal cast of a shoot with super­ posed long leaf cushions was found- in a decayed yellow, clay labelled Gd sW (p. 12). . The whole specimen measures about 4 -8 cm.' long and 0-8 cm. wide. The long leaf cushions which measure- about' 2 mm. broad and 1 -8 cm. long are superposed on one another. Each leaf is contiguous with those to the right and left without leaving any part of the stem surface exposed. In passing across the axis 3-4 leaf cushions would be met. with. This specimen is slightly similar to the fossils figured by Krausel and Weyland (1933, Pl. 5, Figs. 1, 3, 4, 6) from the Middle Devonian of Germany under the name Barrandeina dusliana (Krejci) Stur. But the apex of the leaf cushions of the German specimens is rounded and broader, which shows that our specimens belong to a different species. 350 J. HSO (b) Type 2 (Pl. HI, Fig. 27).—Another internal cast of a shoot with superposed long leaf cushions was found in the calcareous sandstone PSWg. The axis is at least 8 nun. broad, marked by superposed long leaf cushions, about 0 •$ mm. wide and 5 mm. long, which rest closely against each other without leaving the surface of the stem exposed. Occa­ sionally the upper end of the leaf cushions shows an oval area with a s t all elongate scar at the centre o f it,, suggesting a vascular- bundle; but the preservation is far from clear and no views can be safely expressed concerning the structure and affinities o f the plant. Our fossil resembles to a certain extent the specimen figured by Sze (1936, Pl. 2, Figs. 5-6) from Hunan as Protolepidodendron ? arborescens, but the leaf cushions of our specimen are longer and possess an elevated base —a fact which throw§ doubt upon the specific identity of our specimen with the Hunan form. 10. A shoot with crowded lanceolate leaf cushions (PL in, Fig. 30). A small piece of a compressed .shoot about 1*3 cm. in width is shown in Pl. Ill, Fig. 30. It is preserved as an incrustation in a black shale PWVia (p. 12). This axis is marked by more than ten rows o f small leaf cushions. The cushions are lanceolate, about 2 mm. in length and 1 mm. in breadth, spirally arranged and contiguous without leaving the surface o f the stem exposed. Several attempts to .prepare cuticles from -it by maceration failed. It is rather commonly found, in the shale PWVia, and looks very similar to the specimen from Ch’iiching shown in Pl. V, Fig. 51. Some similar fragments were found in Kunming (Pl. 5, Fig. 46). The affinities o f all these plants are unknown. Gothan and Zimmermann (1937) reported some specimens' from the lower part of the Upper Devonian of Germany which are exactly of the same type. The specimens figured by them in Figs. 2a and 2b of Pl. 24 were de­ scribed as having typical superposed leaf cushions. They are very similar to our specimen. 11. Some undeterminable branched axes. Form 1 (Pl. I, Fig. 10).—PL I, Fig. 10 shows fragments of two shoots, (a and b) of the same type.- They are preserved as incrustations in a yellow sandstone labelled WHa. Shoot a is branched; the main axis is about 4 to 7 mm. thick; the branches are only about 1 mm thick and come off at an angle of less than’ 45 degrees. As the specimens are badly decorticated no surface features are visible. Form 2 (Pl. Ill, Fig. 37).—The axis shown in Pl. III, Fig. 37, about 3 -5 mm. thick, is from the bed T^ (p. 12). It is preserved as a flat incrustation in a soft greenish yellow sandstone. A characteristi­ cally slender, branch is seen coming off at about 50 degrees. These branched axes are too fragmentary to be identified. Some fragments shown in PL II, Figs. 12 (at b), PL I. Fig. 19 and Pl. III, Fig. 36 were also found in the bed T1#. DEVONIAN PLANTS FROM CENTRAL YUNNAN 351 There are also some slender dichotomous branches, which were fqund to be very common in the bed One o f them is shown in Pl. I, Fig. 12 to the left of the letter a. The affinity of these shoots is also unknown. 12. Some small ribbon-like branches (Pl. I, Figs. 13, 19 at b; PL It, Fig. 33 at a) In Pl. I, Fig. 13 are shown two small fragments of ribbon-like branches found in a yellow sandstone o f the bed T15 and a grey sand­ stone labelled PWV19 (p. 12). These fragments are 1 mm. in width. One o f them (marked with an arrow) has a distinct central strand. PL II, Fig. 33 shows at a another 'short axis with a clearly marked median strand. This specimen may belong to the same species as the axes above mentioned, but the evidence is insufficient to prove the identity. Besides these forms described.above, there are some carbonised axes (Figs. 6, 14), ranging from 2 mm. to 6 mm. in breadth. They are very fragmentary. I tried in vain to prepare cuticles from them.

B. Specimens from the district of Kunming Some fragmentary specimens were collected by Mr. P. S. T’shong, Assistant Professor in Geology, National Yunnan University, from Chintien, a locality about 12 km. east of the Kunming city. They represent cf. Asteroxylon elberfeldense, Protolepidodendron scharyanum, the Knorria-statQ of Lepidodendroid stems, and some other fragments of stems. 1. cf. Asteroxylon elberfeldense Kr. and W, (PI. IV, Figs. 42 at b, 44 and 45) A few moulds (Pl. IV, Fig. 44) and casts (PL IV, Fig. 42) of some leafy shoots were obtained from a yellowish grey shaly sandstone. They are straight, about 0-7 cm. broad, and covered with numerous small compact scale-like leaves. The leaves measure about 1-3 mm. long and 0-3 mm. broad and are arranged spirally along the axis. These leaves are about 6 in number along the line across the surface of the axis. ‘The moulds are better preserved than the casts. By the aid of plaster I made a new cast from one of the better preserved moulds; this shows pro'perly the shape and arrangement of the scale-like leaves (Pl. IV, Fig. 45). Some pieces of the original cast, were soaked in balsam and then ground into thin sections. In the longitudinal sections a dark brown slender central vascular strand was disclosed. . Some badly-preserved scalariform tracheids are seen. Unfortunately the vascular structures cannot be properly observed in the cross-sections. The external appearance of our specimens resembles closely the fossils from Germany described as Asteroxylon elberfeldense by Krausel and Weyland (1926, pp. 118-26, Pl. 3, Figs. 5-6). 352 J. HSU

2. Protolepidodendron scharyanum Krejci (Pl. IV, Fig. 42 at c) A cast of a piece of leafy shoot is shown in Pl. IV, Fig. 42 at c. It measures about 27 mm. long and 5 mm. broad, and is covered with lenticular leaf cushions. This fossil appears identical with Protolepidodendron scharyanum as described from Chanyi by Halle (1936, p. 11, Pl. 2, Fig. 1-2) and p:om P’oshi (p. 6, Pl. 3, Fig. 25a). 3. Mould of a lepidodendroid stem in Knorria-j/ate • (PL III, Fig. 41) A mould of a.piece of stem in the Knorria-statc is preserved in a yellow coarse sandstone. It measures about 5 -2 cm. long and 2 *7 cm. broad. Hie decorticated leaf cushions are seen spirally arranged along the axis with a space of 7 mm. between each other. These leaf cushions are lenticular, about 5 mm. long and 1-1 *5 mm. broad. A similar kind of mould has been recorded in a Middle Devonian bed from Germany by Krausel and Weyland (1929, pp. 340-441, PL 15, Fig. 2) and is thought to be a decorticated lepidodendroid stem. But the leaf cushions of our specimen are more lenticular in shape, and suggest that the two species are distinct. Specimens have also been recorded.from some localities in Central Yunnan as the Knorria-state of lepidodendroid stems by Halle (1936, pp. 24-26). Unfortunately no figures were given, so we are not able to compare them with our fossil. 4. Cast o f a thick stem with rhombic leaf cushions (Pl. IV, Fig. 40) A cast of a fragmentary piece of decorticated stem was obtained from a purple sandstone. It measures about 6 -5 cm. in length and 4 cm. in breadth, and has a gentle curvature by which the large size of the original stem can be estimated. The surface is brownish in colour and marked with oblique rows of big rhombic areas, which measure about 11 x 7 mm. diagonally, with the long diagonal parallel to the axis of the stem. These marks are connected with the adjacent ones by curves. Along the vertical diagonal of each mark there is a well-developed ridge, about 7 mm. long and 1-2 mm. wide. Some ridges appear to" have a crushed apex, giving a false forked appearance. The general appearance strongly suggests a lepidodendroid stem. So far as I know there is no such kind of fossil recorded from the Middle Devonian. 5. A shoot with crowded lanceolate leaf cushions (Pl. V, Fig. 46) Pl. V, Fig. 46 shows a shoot with crowded leaf cushions pre­ served as a cast in the same bed with Protolepidodendron scharyanum DEVONIAN PLANTS FROM CENTRAL YUNNAN 353 and cf. Asteroxylon elberfeldense. The leaf cushions are lanceolate in shape, about 1-2 mm. long and 0-5 mm. wide, placed in a more or less superposed arrangement along the axis. Although the present speci­ men is somewhat slender (about 8 mm. ‘broad), it is most probably identical with the specimens from P’oshi (Pl. Ill, Fig. 30). Halle (1936, pp. 25-26) .has briefly described some flattened casts from Ch’iiching and P’oshi which seem to be very similar to ours, though they are more than twice as thick. On the other hand, while Halle does not figure his fossils he says they have a certain resemblance with Zalessky’s Heleniella Theodori from the Upper Devonian of the Donetz basin in Russia, with which, to judge by Zalessky’s figure (1931, Pl. V, Figs. 2, 3) our axis cannot be at all closely compared. I am not inclined to compare my fossil with Zalessky’s for the further reason that the present specimen is associated with cf. Asteroxylon elberfeldense and P. scharyanum showing that it came definitely from a Middle Devonian bed, so that it probably has no relationship with the Upper Devonian specimens described by Zalessky (1931). There is another similar specimen recorded from the Upper Devonian of Spitzbergen by Nathorst (1894, Pl. 15; Pl. 2, Figs. 6, 6a). He considers it to be Bothrodendron ? sp. But Nathorst’? specimens are slightly broader than ours and the leaf cushions are rather far apart. 6. Some incrustations of ribbon-like stems (Pl. IV, Figs. 42 at a and 43) PL IV, Figs. 42' a and 43 show some fragmentary ribbon-like stems preserved as incrustations, associated in the same piece o f rock with cf. Asteroxylon elberfeldense and.. Protolepidodendron scharyanum. (Pl. IV, Fig. 42). They are quite straight and about 4-7 mm. wide. The longest fragments measure about 6 cm. long. No branched form has yet been found. The surface is marked with dense striations and both ends appear to be crushed. The central strand is slender and straight. No comparison can be made with any known specimens owing tp the imperfect preservation.

C. Specimens from the district of Ch’iiching

Some specimens bearing plant- fragments were collected by Professor Y. C. Sun of National Peking University from some localities- having Devonian beds, e.g., Yunglunshan, Weikwanshan, Sonlin, etc. Most of them are too fragmentary to be identified, except the specimens of Protolepidodendron scharyanum. Some axes with H-shaped branch­ ing are worthwhile to report as they might be portions of, a plant belonging to the genus Zosterophyllum. Localities of some of these specimens are not accurately known because the labels were mixed up during transit. 354 j. H S$

1. Protolepidodendron scharyanum Krejci (Pl. V, Figs. 48-49) Two specimens are more or less identical to the European species known under the name Protolepidodendron scharyanum Krejci. Specimen a.—Pl. V ,. Fig. 48 shows an enlargement of a, specimen which is represented as an incrustation of the stem preserved in a white coarse sandstone. It measures about 2 *5 cm. in length and 5 cm. in width. Some spirally arranged oval elevations indicate the leaf cushions, of which there are probably eight round the circumference of the stem. They measure about 2 mm. long and 1 mm broad. I have tried to macerate the cuticles from the carbonised surface, but failed. Specimen b.—H ie specimen shown in Pl. V, Fig. 49 represents a shoot with casts of leaf cushions, preserved in a grey sandstone from. Weikwanshan. It measures about 4 cm. long and 4 mm. broad at the middle, with the basal end rather markedly broadened in a peculiar manner which tends to throw some doubt upon the identity of the fossil with P. scharyanum. I have not seen this feature mentioned or figured by any author in this species. But if our fossil really belongs to P.\scharyanum it would be difficult to reconcile Krausel and Weyland’s reconstruction (1932, p- 398) with our Pl. V, Fig. 49. The leaf cushions are somewhat fusiform in shape with their maximal length about 4 mm. _About 4 cushions are met with in passing across the upper (cylindrical) part of the stem. The .first specimen is compared with that figured by Kr&usel and Weyland from Germany (1929, Text-fig. 22). Yet my specimen is rather smaller. The arrangement o f the leaf cushions agrees closely with that in the specimens described by Halle (1936, Pl. 2, Figs. 2 and 14) and by Krausel and Weyland (1932, p. 323, Figs. 2 and 3). The second specimen also appears closely similar to those found in Chanyi (Halle, 1936, PL 2, Figs. 1-2), P’oshi (Pl. 3, Fig. 25a) and Kunming (Pl. 4, Fig. 42 at c), except for the peculiar enlargement of the axis at one end.

2. Axes with H-shaped branching {cf. Zosterophyllum) (Pl. V, Fig. 52 and Text-figs. 5 a-c) Several specimens in the collection from Ch’uching, although pborly preserved and sterile, suggest by their habit that they may belong to the genus Zosterophyllum which has been described from various Silurian and Lower Devonian localities in Europe, North America and Australia. Fig. 52 of Pl. V and Text-figs. 5a-c show a kind of plant with a peculiar more or less H-shaped branching, preserved as incrustations in a soft brown clay. The first fragment (a) has a main axis 5 mm. broad, which gives off a slightly thinner lateral branch (about 3 mm. broad) at an angle o f about 50 degrees. A t about 1 cm. from the main DEVONIAN PLANTS FROM CENTRAL YUNNAN 355' axis the lateral branch gives off at an angle of about 65 degrees a still finer branch about 2-5 mm. thick. The second fragment (b) follows a peculiar wavy course. The third fragment (Text-fig. 5c) shows a mode of branching essentially like that of the first, but the lateral branch curves round into a position almost-'parallel to the main axis.

Text-fig. 5. Axes with H-shaped branching (cf. Zosterophyllum). All x 1.

The axes are blackish-brown in colour and have a smooth surface with a carbonised crust. Peel sections were tried but no cell structures were observed. These fossils recall specimens of Zosterophyllum found in the Late Silurian of Australia (Cookson, 1935, Pl. 10, Figs. 13—15), and in the Lower Devonian of Scotland (Lang, 1927, Pl. 1, Figs. 7-9), England (Croft and Lang, 1942, Pl. 11, Figs. 67-68) and Germany (Krausel and "Weyland, 1935, pp. 175-77). But a specific identification must await the discovery of more perfect specimens.

3. A shoot with crowded lanceolate leaf cushions (Pl V, Fig. 51) A small piece of the cast of a compressed shoot found from Sonlin (Pl. V, Fig. 51) measures about 1 -3 cm. in breadth. It has spirally ar­ ranged small lanceolate leaf cushions. The cushions measure 1 -5 mm. in length and 0-5 in breadth and are located 1 mm. apart. The leaf cushions are rather crowded and there appear to be 9-10 in a line across the surface of the stem. ' It is identical with the specimens from P ’oshi (Pl. 3, Fig. 30) and Kunming (Pl. 5, Fig. 46). From the same district (Ch’uching) as our specimen figured in Pl. V, Fig. 51, Halle (1936, p. 25) has briefly de­ scribed some flattened casts which seem to be very similar to our speci­ mens. I have discussed them already. Considering the occurrence of this kind of plant in a Middle Devonian bed in Kunming, the bed containing this plant is also probably of Middle Devonian age. 356 J. HStJ

4. Some ribbed axes (Pl- V,-Figs. 50, 53, 54) A ribbed axis shown in Pl. V, Figs. 53 and 54 represents a kind of plant preserved as incrustations in a yellow sandstone from Yunlun- shan. It measures about 1 cm. broad. N o leaves are seen attached to it. It looks very similar toS the specimens from P ’oshi (PL 3, Figs. 32, 35) which are considered probably to be axes o f Protovteridium minutum Halle. Another specimen,, shown in PL V, Fig. 50, represents apiece of cast of a compressed ribbed axis, also from Yunlunshan, which is about 2 -2 cm. in width. The surface of this specimen appears' less ribbed than the fossil above described. Most probably they-belong to different kinds of plants. 5. Mould o f an axis with long leaf cushions (PL V, Fig. .47) PL V, Fig. 47 shows a mould of an axis with long leaf cushions pre­ served in a coarse pinkish grey sandstone bed iii Yunlunshan. It mea­ sures about 8 mm. broad.:-' The surface is marked by long cushions, which are about 2 mm. long and 2-2 *5 mm. broad, continuous and spirally arranged. It resembles to some extent the specimen figured in Pl. 3, Fig. 31 from P’oshi.

D. Specimen from the district of Luch’uan

A well-preserved specimen wa.s presented to me by the Geological Survey of Yunnan. It is said to have been collected from a Devonian bed in the district of Luch’uan.

Sublepidodendron sinensis sp. nov. (Pl. V, Figs. 55, 56). Pl. V, Fig. 55 shows a well preserved mould of an axis in a white sandstone. The diameter of this specimen is about 1 cm. The longest specimen is still, with the Geological Survey of Yunnan; it measures about 7 cm. No branched form has yet been found. • Fig. 56 of Pl. V represents an artificial cast of the same specimen made in plaster. The leaf cushions are circular to lenticular in shape with two taperir^ ends. They measure about 2 mm. long and 1 mm. wide and are spi­ rally arranged around the axis. In passing across the stem 5-7 leaf cushions will be met with. The distance between the cushions is about 1 -5 mm. Each square centimeter of the surface of the axis bears about 33 cushions. These cushions have a swollen margin encircling a lenticulate depression (seen in the cast). Neither a ligule print nor a vascular scar is.seen on the mould. Between two contiguous cushions of the same row there is a ridge connecting the base of the upper DEVONIAN PLANTS FROM CENTRAL YUNNAN 357 cushion with the apex of th e'Other. The surface of the stem appears to be wrinkled. This kind of specimen is quite distinct from the oth'er specimens found in Yunnan. In some , ways it recalls some specimens from the Upper Devonian of the Donetz • Basin, Russia? .and of Waldenburg, Germany. Of the Russian fossils, it resembles to some extent Heleniella Theodori Zalessky (1931, Pl. 4, Figs. 5, 6-6a; Pl. 5, Fig. 2; Pl. 7. Figs, 6-6a), but my specimen is more slender and the leaf scars are crowded and more oval than lenticular. Among the German specimens, it seems closer to Sublepidodendron antecedens Gothan and Zimmermann (1937, Pl. 22, Fig. 1 a-c), but my specimen is still much' more slender and possesses crowded leaf cushions, so no close comparison with any of the recorded species is possible. According to the opinions of the above mentioned authors the genus Heleniella has some charac­ ters closer to Sigillaria (Zalessky, 1931, pp. 572-73),, while the other genus Sublepidodendron (Gothan and-Zimmermann, 1937, pp. 489-92) is considered to be closer to Lepidodendron. Although the cushions of our specimen are no doubt placed in vertical orthostichies, yet the arrangement appears to be more spiral than superposed. If this character is considered, our specimen may be better named as a Sub­ lepidodendron. But its relationship with Lepidodendron is still obscure. So the name ? Sublepidodendron sinensis sp. nov. is proposed. Diagnosis.—Stem straight, round, about 7 mm. in diameter, wrinkled, crowded with leaf scars. Leaf cushions circular to lenticular in shape, about 2 mm. long and 1 mm. wide, slightly tapering at both ends and with two swollen margins encircling a lenticular depression. Neither ligule print nor vascular scars visible. Leaf cushions spirally arranged round the axis but sometimes superposed with a ridge connecting the two contiguous cushions. Cushions about 1 -,5 mm. distant, each square centimetre 'of the. surface o f the axis bearing about 33 cushions. This fossil suggests a slightly younger age (? Upper Devonian) for the bed from which it has been collected.

III. Discussion and Conclusion

This investigation deals with 45 specimens collected from several localities in the districts of Lihsien, Kunming, Ch’iiching, and Luch’iian. Most of them are too fragmentary to furnish specific identifications. Specimens referable to Protolepidodendron scharyanum Krejci are the commonest. Tceniocrada cf. dubia Kr. and W.3 Asteroxylon cf. elberfeldense Kr. and.W., and cf. Zosterophyllum are of great interest and are here recorded for the first time from Asia. Other fossils are provisionally referred to Drepanophycus spinceformis Goeppert, Protopteridium minutum Halle, Barrandeina, Hostimella, Protolepido­ dendron ? arborescens Sze, Leptophlamm australe McCoy, and Heleniella Theodori Zalessky. Several fragments of the decorticated stems of some lepidophytic plants are described. One new species ? Sublepido­ dendron sinensis has been created. 358 J. HSU

Attempts at cuticle preparations have been made, but do not yield good results. The axis of Tceniocrada cf. dubia has revealed a cutinised epidermis but hardly any details are visible; an interesting fact is that the vascular bundle contains tracheids with bordered pits. These characters suggest that T. dubia was not a submerged aquatic plant. It is obvious that the flora represented by these specimens in all the four districts is of Devonian aspect, and at least in each of the first three districts, Lihsien, Kunming and Ch’tiching, it is o f Lower to Middle Devonian affinities. The specimens from the bed T]8, of Itate and Ludonduan in the P’oshi region of the Lihsien district have been determined as Proto- lepidodendron scharyanum, Tceniocrada cf. dubia, Asteroxylon cf. elberfeldense and cf. Protopteridium minutum. A specimen from the bed T1?i. of the same (Itate and Ludonduan) series is cf. Drepanophycus spinceformis. This fact suggests that these two beds are probably of later Lower Devonian age, because specimens referred to the.genus Tceniocrada are hitherto known 'only* from the Lower Devonian (Krausel and Weyland, 1930; Steinmann and Elberskirch, 1928; Stockmans 1940; Croft and Lang, 1942; Corsin, 1933 and Dorf and COoper, 1943), while Protolepidodendron scharyanum and Asteroxylon elberfeldense are generally found in the Early Middle Devonian. Some of the specimens collected from the bed Tls are identical' with Proto-' lepidodendron scharyanum. Specimens from other localities in P’oshi are referable to Drepanophycus spinceformis, Protopteridium minutum, Barrandeina, Hostimella, Protolepidodendron‘I . arborescens, Lepto- phlasum australe, and Heleniella Theodori, and several fossils are identical with Protolepidodendron scharyanum. Although the exact geological ages of these rocks are very difficult to judge from these fragmentary specimens, yet on the whole they show a Middle Devonian aspect. Some specimens from Kunming are identical with Protolepido­ dendron scharyanum. Several specimens are closely comparable to Asteroxylon elberfeldense. One fossil possessing superposed lanceo­ late leaf cushions-(Fig. 46) is identical with those collected from P ’oshi and from a locality in Ch’iiching (Figs. 30 and 51); this fact also shows that the geological age of these beds may be Middle Devonian. Other interesting specimens are a cast and a mould of some lepidophytic stems. The specimens from Ch’iiching represent Protolepidodendron scharyanum, cf. Zosterophyllum, and a shoot crowded with lanceolate leaf-cushions. The fossil cf. Zosterophyllum is of great interest because this genus has so far been only recorded from the Late Silurian of Australia (Lang and Cookson, 1930; Cookson, 1935) and from the Lower Devonian o f Scotland (Lang, 1927), England (Lang, 1937), France (Corsin, 1933), Germany (Krausel and Weyland, 1933) and America. This suggests that there is a Lower Devonian bed in Ch’iiching.

* See foot-note to page 346 above. DEVONIAN PLANTS FROM CENTRAL YUNNAN 359

The new species 'I Sublepidodendron sinensis, found in Luch’tian, has some resemblance to the Early Upper Devonian plant Sublepido­ dendron antecedens Gothan and Zimmermann (1937, p. 489, Pl. 22, Figs. la, 1 b and lc) from Germany. Although this work is of much interest it is* far from satisfactory owing to. the fragmentary nature of the material. However, it strongly suggests that there is a promising field for further investigation at these localities. l i t e r a t u r e c i t e d

Colani. M. (1919) “ Sur quelques vegetaux Paleozoiques,” Bull. Surv. Geol. Indochine, 6, Fasc. 1, 1-21, 2 pis. Cookson, I. (1935) “ On plant-remains from the Silurian o f Victoria, Australia, that extend and connect floras hitherto described,” PM . Trans. Roy. London, Ser. B, 225, N. 531, 127-48, pis. 10-11. Coran, P. (1933) “ Decouverte d’une flore dans le Devonien inferieur du Pas-de-Calais,” Compt. Rend. Seances Acad. Sci., X. 197, 180. Croft, W. N. and “The Lower Devonian flora of the Senni beds of Lang, W. H. (1942) Monmouthshire ami. Breconshire,” Phil. Trans. Roy. Soc. Land. Ser. B., 231, No. 579, 131-63, pis. 9-11. Dorf, E. and Cooper, “Early Devonian plants from Newfoundland,” J.R. (1943) Jount. Pedeeont., 17, No. 3, 264—'Tfi. Gothan, W. and “Weitsres uber die alt-oberdevonische Flora von Zimmermann, F. (1937) Bogendorf-Iibichau bei Waldenburg,” Jahrbuch Preuss. GeoL landesanstalt. Bd. 57, 487-506, pis. 22- 26. . Halle, T. G. (1927) “ Fossil plants from South-Western China,” Palceontologia Sinica, Ser. A, 1,' Fasc. 2. ------£1936) “ On Drepanophycus, Protolepidodendron and Proto- pteridium, with notes on the Palaeozoic flora of Yunnan,” ibid., Ser. A, 1, Fasc. 4, 5-28, pis. 1-5. Hoeg, O. A. (1937) “The Devonian Floras and their bearing upon the origin of vascular plants,” Bot. Rev., 3, 563-92. * :— (1942) “The Downtonian and Devonian flora of Spits­ bergen,” NorgesSvalb. Ish.-Und.,' 1-228, 35 text- figs. and 62 plates. Kidston, R. and “ On Old Red Sandstone plants, showing structure, Lang, W. H. (1920) from1 the Rhynie Chert Bed, Aberdeenshire. Part III Asteroxylon Mdckiei,, K. and W„” Trans. Roy. Soc. Edlnb., 52, Part 3, No. 26., Kr&usel, R. (1938) . “Psilophytineaj,” in Manual of Pteridology, 496-99. ------und Weyland, H. “ Beitrftge zur Kenntnis der Devonflora. II,” (1926) Abhand. Senck. Natur. Ges., 40, 113-155, pis. 3-15. ------(1929) .. “ BeitrSge zur Kenntnis der Devonflora. Ill," ibid., 41, 315-60, pis. 1-19. (1930) “ Die Flora des deutschen Unterdevons,” Abhandl. Preuss. Geol. Landesanstalt. N.F. 131* 4-92, pis. 14.

* I much regret that this important memoir came to hand too late for me to make use of it for the present work. 25 360 J. HStf

Krausel, R. und “Pflanzenreste aus dem Devon. IV. Protolepido­ Weyland, H. (1932) dendron” ibid., 14, 391-406. ------(1933) .. “Die Flora des Bohmischen Mitteldevons,” Palceonto- graphica, . 78, Abt «B., 1-46, pis; 1-7. ------(1935) .. “Neue Pflanzenfunde im Rbeinischesi Unterdevon.” ibid., 80 B, 171-90, pis. 41-44. ------:— (1937) .. “D ie Verbreitung der Devonfloren,” Compt. Rend. 2e Congr. Strat. Carboruf, 1935, T 2, 527-37. Ku, C. V. * On the Devonian o f P'oshi, S. Yunnan (unpublished paper). Lang, W . IL (1927) . . “Contribution to the study of the Old Red Sandstone flora o f Scotland. VI. On Zosterophyllum myretonianum Penb. and some other ptont- remains from the Carmyllie beds o f the Lower Old Red Sandstone,” Trans. Roy. Soc. Edinb., 55. 443-52, pis. 1-2. — — ■ (1932) “ Contributions to the study of the Old Red Sandstone flora of Scotland. VUI. On Arthrostigma, Psilophyton, and some associated plant remains from the Strathmore beds o f the OtteHnniap Lower 'Old Red Sandstone,” ibid., 57, 491-521, pis. V 4. — ------and “ Some fossil plants of early Devonian type from the Cookson, I. (1930) Walhalla Series, Victoria, Australia,” Phil. Trans. Roy. Soc., London* B 219, 133-63, pis. 3. Seward, A. C. (1910) ... Fossil Plants, VoL n . ------— (1941) Plant life through the ages, p. 144 (Reprinted edition). Stemmann, G. and “ Neue bemerkenswerte Funde im altesten Unter- Elberskirch, W. (1928) devon des Wahribachtales bei Siegburg,” Ber. Versamm. Niederrhein. Geolog. Vereins, 1-74, pis. 2. Stockmans, F. (1940) .. “ VSgStaux E’od<5voniens de la Belgique,” Mem. Mus. Hist. Nat. Belt., No. 93, 1-90, pis. 11. Sze, H. C. (1936) ;. “ Ueber einen baumftirmigen Lepidophytenrest in der Tiao-Ma-Chiea Series in Hunan,” Bull. Geol. Soc. China, 15, No. 1, 109-16, pis. 2. ■------(1941) “A new occurrence o f the oldest land plant from the Chao-Tung District, Yunnan,” ibid., 21} No. 1, 107-10, pl. 1. Walton, J. (1926) “ On some Australian fossil plants referable to the genus Leptophhum Dawson,” 'Mem. and Proe. Manchester Lit. and Phil. Soc,, 70, No. 10, 113-18, pl. 1. Weyland, H. (1925) > “ Die Flora des Elberfelder Mitteldevons in ihrer Bedeuturig fur did Kenntnis der gesamten Devonflora,” Jahresbericht des Naturwissens- chaftlichen Vereins, Elberfeld, 15, 33-47, pis. 2. Zalessky, M. D . (1931) “ V6g6taux nouveaux du Devonian Sup^rieur du Bassin du Donetz,” Bull. Acad. Sci. U.S.S H 1931, 557-97, pis. 8.