Hostname: page-component-745bb68f8f-f46jp Total loading time: 0 Render date: 2025-02-11T12:09:57.624Z Has data issue: false hasContentIssue false
  • English
  • Français

The palaeogeographical significance of specimens attributed to Protolepidodendron scharyanum Krejči (Lycopsida) from the Middle Devonian of North Xinjiang, China

Published online by Cambridge University Press:  19 December 2007

HONG-HE XU  and
YI WANG
HONG-HE XU*
Affiliation:
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
YI WANG
Affiliation:
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing 210008, People's Republic of China
*
*Author for correspondence: honghexu@hotmail.com
Rights & Permissions [Opens in a new window]

Abstract

Morphology of the leaves of stem compressions originally attributed to Protolepidodendron scharyanum from the Middle Devonian of North Xinjiang, China is reinvestigated. The leaf is three-dimensional, consisting of one central abaxial segment and four lateral adaxial segments, and does not conform to the once bifurcate leaf of Protolepidodendron. Specimens are therefore transferred to Leclercqia cf. L. complexa. This is the first unequivocal report of the genus Leclercqia in China based on complete leaf morphology. The distribution of Leclercqia is discussed, demonstrating a more or less cosmopolitan genus in the Middle Devonian. The Middle Devonian flora of North Xinjiang shows great similarity to that of Venezuela and North America, and almost no relationship with that of Yunnan, South China.

Keywords

XinjiangLeclercqiaProtolepidodendronDevonianpalaeogeography
Type
Rapid Communication
Information
Geological Magazine , Volume 145 , Issue 2 , March 2008 , pp. 295 - 299
Copyright
Copyright © Cambridge University Press 2007

1. Introduction

Middle Devonian herbaceous lycopsids are widely accepted to have palaeobiogeographical significance if their leaf morphology has been correctly worked out and documented allowing accurate generic and specific determination (Bonamo, Banks & Grierson, Reference Bonamo, Banks and Grierson1988). There remain a few cases where historically important lycopsid discoveries have yet to be reinvestigated to determine their exact leaf morphology. One example is the report of Protolepidodendron scharyanum Krejči (the name should be P. scharianum Kräusel et Weyland, see Xu & Wang, in press) from Xinjiang, NE China. Specimens originally determined by Sze (Reference Sze1960, Reference Sze1961) on the basis of once-divided leaves were later re-assigned to P. cf. cathaysiense Schweitzer et Cai by Cai & Wang (Reference Cai, Wang and Li1995) who noticed one leaf that appeared to trifurcate. The question of the exact determination was left ambiguous as no spines were visible on the margin of leaves.

The identification of these specimens is important because of their palaeogeographical situation. Protolepidodendron Krejči ex Gothan (for authorship see Xu & Wang, in press) is generally held to refer to a herbaceous lycopsid with once-bifurcate leaves (Gothan, Reference Gothan1921, pp. 225–6). Most specimens previously attributed to Protolepidodendron have been reassigned to Leclercqia Banks, Bonamo et Grierson (Reference Banks, Bonamo and Grierson1972), which has a five-tipped leaf with a prominent central elongate segment and two pairs of shorter lateral segments (Banks, Bonamo & Grierson, Reference Banks, Bonamo and Grierson1972; Fairon-Demaret, Reference Fairon-Demaret1974, Reference Fairon-Demaret1980, Reference Fairon-Demaret1981), and is found widely in Laurentia and Gondwana (Meyer-Berthaud et al. Reference Meyer-Berthaud, Fairon-Demaret, Steemans, Talent and Gerrienne2003). However Protolepidodendron from Yunnan, South China (Halle, Reference Halle1936; Schweitzer & Cai, Reference Schweitzer and Cai1987) was transferred to Minarodendron Li (Reference Li1990), characterized by trifurcate spiny leaves. Minarodendron (Protolepidodendron) cathaysiense Li (Reference Li1990) is restricted to South China, the only plate yet to show a strongly endemic Middle Devonian macroflora (Wang et al. Reference Wang, Berry, Hao, Xu and Fu2007). The palaeogeographical positions of the Kazakhstania plates, on one of which the locality was situated (Liao & Ruan, Reference Liao, Ruan, Zhou and Lin1995), in the Middle Devonian is problematical (Scotese & McKerrow, Reference Scotese and McKerrow1990; Cocks & Torsvik, Reference Cocks and Torsvik2002; Torsvik & Cocks, Reference Torsvik and Cocks2004). This investigation is to demonstrate the true leaf morphology of Sze's (Reference Sze1960, Reference Sze1961) specimens and therefore to determine if they show affinity to the more or less cosmopolitan herbaceous lycopsid flora or the endemic flora of Yunnan.

2. Material and methods

The detailed locality and horizon was not stated by Sze (Reference Sze1960, Reference Sze1961), according to whom all materials were collected from the Hoxtolgay area, Hoboksar Mongol Autonomous County, North Xinjiang, NW China. The fossil-bearing horizon also yielded Hostimella sp., Lepidodendropsis? (Colpodexylon?) arborescens Sze, and Lepidodendropsis? dzungariensis Sze. The horizon is inferred to be the Hujiersite Formation (Givetian) from this fossil plant assemblage (Cai & Wang, Reference Cai, Wang and Li1995). A few localities (Fig. 1) are probably involved. More recently reported plants from the Hujiersite Formation of the Hoxtolgay area include: Sawdonia curstipa Wang & Hao (Reference Wang and Hao1996), Haskinsia sagittata (Cai & Wang, Reference Cai, Wang and Li1995; Xu et al. in press), H. hastata (Xu et al. in press), Colpodexylon gracilentum (H.-H. Xu, unpub. Ph.D. thesis, Nanjing Institute of Geology and Palaeontology, 2006), Tsaia conica (Wang et al. Reference Wang, Xu, Fu and Tang2004), and Compsocradus sp. (H.-H. Xu, unpub. Ph.D. thesis, Nanjing Institute of Geology and Palaeontology, 2006).

Figure 1. Generalized geological and geographical map showing probable localities of Sze's (Reference Sze1960, Reference Sze1961) collection in Xinjiang, NW China, and the relative generalized position of the Yunnan Middle Devonian flora.

A total of six specimens (PB3246–PB3251) attributed to Protolepidodendron scharyanum by Sze are preserved as compressions and deposited at Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences. A short leafy stem on the reverse side of Sze's specimen PB3246 was uncovered using serial dégagement (Fairon-Demaret, Hilton & Berry, Reference Fairon-Demaret, Hilton, Berry, Jones and Rowe1999). Leaves on the counterpart to Sze's specimen PB3246 (PB3247) are also illustrated. Macrophotography was carried out using a Nikon D100 digital camera with cross-polarized illumination.

3. Description

The new fragmentary unbranched axis with persistent leaves described here is 22mm long and 3.8–4.2mm wide (Fig. 2a). The surface of the stem was highly compressed, so that it is hard to recognize patterns of leaf bases. Leaves in profile are linear with a swollen base, showing an abaxially recurved tip (Fig. 2a, leaves 1, 3 and 4) distal to a division, or a division to form two or more segments (Fig. 3). The angle between leaf and stem ranges from 40° (Fig. 2a) to 50° (Fig. 2b).

Figure 2. Leclercqia cf. L. complexa from the Middle Devonian of North Xinjiang, China. (a) New discovered short leafy stem on the reverse side of PB3246 (Sze, Reference Sze1960, Reference Sze1961). (b) Enlargement of leaves in Sze's unprepared specimen PB3247, upper leaf partially prepared, four segments visible distally (arrow); lower unprepared leaf shows typical bifurcation as observed in Protolepidodendron scharyanum Kräusel et Weyland. (c, d) Stages of serial dégagement to the leaf 2 in (a). Lettering of segments follows Fairon-Demaret (Reference Fairon-Demaret1980). All scale bars = 1mm.

Figure 3. Leclercqia cf. L. complexa from the Middle Devonian of North Xinjiang, China. Line drawings of leaves in Figure 2. (a) Arrowed leaf in Figure 2b; (b,c,d) correspond to leaves 5, 4 and 3 in Figure 2a; (e,f,g) three stages of serial dégagement to the leaf 2 in Figure 2a (f and g correspond to Fig. 2c and d). Lettering of segments follows Fairon-Demaret (Reference Fairon-Demaret1980). Scale bar = 2mm.

Serial dégagement was performed on leaf 2 (Fig. 2a). Like most partly prepared leaves, this leaf shows three segments (b, c and d in Fig. 3e) before dégagement. In addition, an obvious wider segment was buried in the matrix under the segment d (Fig. 3e). After removing segment d, the long central segment E was finally exposed (Fig. 2c; Fig. 3f). Segment a was also revealed after segment b was removed (Fig. 2d; Fig. 3g).

The unforked part of the leaf is 0.33–0.41mm wide. The leaf divides 3.4–3.8 (mean 3.61, n=4)mm from the base, forming a long central segment (up to 3.1mm long, Fig. 2a, leaf 3; Fig. 3d) recurved abaxially and a pair of lateral laminae that each bifurcates proximally into two slender segments 0.77–1.54mm in length. The arrangement of all five segments is always three-dimensional. It is impossible to discern the proximal ends of all segments. In some leaves, four distal segments could be seen at the same time, e.g. Sze's (Reference Sze1960, Reference Sze1961) specimen PB3247 (Fig. 2b, arrow; Fig. 3a); leaf 5 on the new stem (Fig. 2a; Fig. 3b).

4. Discussion

Bifurcate leaves were for a long time accepted as a distinctive character of the genus Protolepidodendron. Schweitzer & Cai (Reference Schweitzer and Cai1987), for the first time, noted the trifurcate and spiny microphylls in specimens previously attributed to P. scharyanum by Halle (Reference Halle1936) from the Middle Devonian of Yunnan, South China, and placed the specimens in a new species, P. cathaysiense, effectively enlarging the generic concept. Additional specimens of P. cathaysiense were studied by Li (Reference Li1990). Multiperforate bordered pits in the tracheids, as well as the trifurcate leaves, supported transfer to the new genus Minarodendron Li. Minarodendron is widely accepted as an endemic lycopsid that is probably related to Leclercqia (Kenrick & Crane, Reference Kenrick and Crane1997). Therefore Protolepidodendron is no longer recognized in South China.

Cai & Wang (Reference Cai, Wang and Li1995) re-examined Xinjiang specimens attributed to P. scharyanum, from which three leaf distal segments were recognized (Cai & Wang, Reference Cai, Wang and Li1995, pl. 16, figs 1, 2). Specimens were transferred to Protolepidodendron cf. P. cathaysiense. However we recognize three-dimensional, five-tipped leaves from the newly studied leafy stem, and the specimens should therefore be reassigned to Leclercqia.

The type species, L. complexa, at the type locality in New York State, was measured as: stem 3.5–7.0mm wide, leaf 4.0–6.5mm long as a whole and bearing one-half to two-thirds of its length a pair of lateral divisions. The central and the lateral segments of the leaf are 2.5–3.0mm and 1.0–2.0mm long respectively (Banks, Bonamo & Grierson, Reference Banks, Bonamo and Grierson1972). These measurements are well matched with dimensions of the present plant. No information about the ligule, sporophylls, sporangia, spores or anatomy was available, so, it is proper to attribute the present plant to Leclercqia cf. L. complexa (cf. Berry, Reference Berry1994). L. complexa differs from a second species, L. andrewsii Gensel et Kasper, from the Lower Devonian of New Brunswick, Canada (Gensel & Kasper, Reference Gensel and Kasper2005), in that the median and lateral segments of the leaf in the latter are all in one plane and adaxially recurved.

In view of the above, Sze's (Reference Sze1960, Reference Sze1961) specimens of P. scharyanum, assigned to P. cf. cathaysiense by Cai & Wang (Reference Cai, Wang and Li1995), are hereby transferred to L. cf. complexa. This is the first confirmed record of Leclercqia on the basis of demonstration of leaf morphology in Chinese Middle Devonian strata.

Until now, the Middle Devonian lycopsid flora of North Xinjiang contains Haskinsia sagittata Edwards et Benedetto (Cai & Wang, Reference Cai, Wang and Li1995), H. hastata Berry et Edwards (Xu et al. in press), Colpodexylon Banks, Archaeosigillaria Kidston (Dou et al. Reference Dou, Sun, Wu and Gu1983) and Leclercqia (this work). The floral assemblage shows much more similarity to that of North America (see Grierson & Banks, Reference Grierson and Banks1963, Reference Grierson and Banks1983) and Venezuela (see Berry, Casas & Moody, Reference Berry, Casas and Moody1993; Berry & Edwards, Reference Berry and Edwards1995, Reference Berry and Edwards1996) than to that of the Xichong Formation, Yunnan (Wang et al. Reference Wang, Berry, Hao, Xu and Fu2007). The only exception is an unusual form of Colpodexylon in Yunnan (Schweitzer & Cai, Reference Schweitzer and Cai1987), new specimens of which show no Colpodexylon (‘embayed xylem’ – Banks, Reference Banks1944) structure and which therefore may be transferred to a new genus (Y. Wang et al. unpub. data). The transfer of P. cf. cathaysiense to Leclercqia therefore emphasizes the palaeophytogeographical separation of North Xinjiang from Yunnan.

Since its establishment, Leclercqia has been reported from the Early to Middle Devonian more or less worldwide, including the type locality in New York State, USA (Banks, Bonamo & Grierson, Reference Banks, Bonamo and Grierson1972), Australia (Fairon-Demaret, Reference Fairon-Demaret1974; Meyer-Berthaud et al. Reference Meyer-Berthaud, Fairon-Demaret, Steemans, Talent and Gerrienne2003), Germany (Fairon-Demaret, Reference Fairon-Demaret1980), Belgium (Fairon-Demaret, Reference Fairon-Demaret1981), Venezuela (Berry, Reference Berry1994), New Brunswick, Canada (Gensel & Kasper, Reference Gensel and Kasper2005; Gensel & Albright, Reference Gensel and Albright2006) and Xinjiang, China (this work). The position and boundaries of the plates that later make up the Kazakhstania plate are uncertain in Middle Devonian time (Torsvik & Cocks, Reference Torsvik and Cocks2004). Middle Devonian plant localities in North Xinjiang and Kazakhstan were potentially close or even on the same microplate (Liao & Ruan, Reference Liao, Ruan, Zhou and Lin1995) and have similar members of Middle Devonian flora (Ananiev, Reference Ananiev1960; Jurina, Reference Jurina1988; Cai & Wang, Reference Cai, Wang and Li1995). It is likely that some Kazakhstan specimens currently attributed to Protolepidodendron may be transferred to Leclercqia after further investigation.

Evidence from spores supports the occurrence of Leclercqia in North China. As the dispersed spore Dibolisporites heitaiensis Ouyang (Reference Ouyang1984) from the Middle Devonian of Heilongjiang, NE China, shows great similarity to the in situ spore of L. complexa (Richardson, Bonamo & McGregor, Reference Richardson, Bonamo and McGregor1993), Ouyang (Reference Ouyang1984) suggested that megafossils of Leclercqia would probably be discovered from the Middle Devonian of North China as well as Siberia. Geng (Reference Geng1992) reported L. complexa from the Lower Devonian (Pragian) of Sichuan, South China. But the assignment was rejected (Cai & Wang, Reference Cai, Wang and Li1995) because of the lack of typical features of Leclercqia.

When marked on the Middle Devonian paleogeographical and palaeoclimatic reconstruction, occurrences of Leclercqia are widely distributed, most of which are in the arid climatic belt (Meyer-Berthaud et al. Reference Meyer-Berthaud, Fairon-Demaret, Steemans, Talent and Gerrienne2003). Leclercqia in Xinjiang suggests a tropical distribution. Considering the occurrence also in the warm temperate climatic belt (Venezuela: Berry, Reference Berry1994), we suggest that Leclercqia is more or less cosmopolitan in the Middle Devonian, with the only notable exception being South China, rather than distributed in the same so-called arid climatic belt as proposed by Meyer-Berthaud et al. (Reference Meyer-Berthaud, Fairon-Demaret, Steemans, Talent and Gerrienne2003).

Acknowledgements

We thank Dr Wang Q., Institute of Botany, Chinese Academy of Sciences, for helpful suggestions. The work is supported by National 973 Project (No. 2006CB806400) and NSFC No. J0630967.

References

Ananiev, A. R. 1960. Studies on the Middle Devonian of the Altai-Sayan mountain region. Botanicheskii Zhurnal 45, 649–66 (in Russian with English abstract).Google Scholar
Banks, H. P. 1944. A new Devonian lycopod genus from southeastern New York. American Journal of Botany 31, 649–59.CrossRefGoogle Scholar
Banks, H. P., Bonamo, P. M. & Grierson, J. D. 1972. Leclercqia complexa gen. et sp. nov., a new lycopod from the late Middle Devonian of eastern New York. Review of Palaeobotany and Palynology 14, 19–40.CrossRefGoogle Scholar
Berry, C. M. 1994. First record of the Devonian lycophyte Leclercqia from South America. Geological Magazine 131, 269–72.CrossRefGoogle Scholar
Berry, C. M., Casas, J. E. & Moody, J. M. 1993. Diverse Devonian plant assemblages from Venezuela. Documents Laboratoire Géologique de Lyon 125, 29–42.Google Scholar
Berry, C. M. & Edwards, D. 1995. New species of the lycophyte Colpodexylon Banks from the Devonian of Venezuela. Palaeontographica B 237, 59–74.Google Scholar
Berry, C. M. & Edwards, D. 1996. The herbaceous lycophyte Haskinsia Grierson and Banks from the Devonian of western Venezuela, with observations on leaf morphology and fertile specimens. Botanical Journal of the Linnean Society 122, 103–22.Google Scholar
Bonamo, P. M., Banks, H. P. & Grierson, J. D. 1988. Leclercqia, Haskinsia, and the role of leaves in delineation of Devonian lycopod genera. Botanical Gazette 149, 222–39.CrossRefGoogle Scholar
Cai, C.-Y. & Wang, Y. 1995. Devonian floras. In Fossil floras of China through the geological ages (ed. Li, X.-X.), pp. 28–77. Guangzhou: Guangdong Science and Technology Press.Google Scholar
Cocks, L. R. M. & Torsvik, T. H. 2002. Earth geography from 500 to 400 million year ago: a faunal and palaeomagnetic review. Journal of the Geological Society, London 159, 631–44.CrossRefGoogle Scholar
Dou, Y.-W., Sun, Z.-H., Wu, S.-Z. & Gu, D.-Y. 1983. Palaeobotany. In Palaeontological Illustrations of Northwest China, Xinjiang Uygur Autonomous Region, Vol. 2 (eds Geological Surveying Team and Institute of Geoscience, Xinjiang Bureau of Geology, Geological Surveying Department, Xinjiang Bureau of Petroleum), pp. 561–614. Beijing: Geological Publishing House (in Chinese).Google Scholar
Fairon-Demaret, M. 1974. Nouveaux specimens du genre Leclercqia Banks, H. P., Bonamo, P. M. et Grierson, J. D. 1972 de Givetian (?) du Queensland (Australie). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 50, 1–5.Google Scholar
Fairon-Demaret, M. 1980. A propos des spécimens déterminés Protolepidodendron scharianum par Kräusel et Weyland, 1932. Review of Palaeobotany and Palynology 29, 201–20.CrossRefGoogle Scholar
Fairon-Demaret, M. 1981. Le genre Leclercqia Banks, H. P., Bonamo, P. M. et Grierson, J. D. 1972 dans Dévonien Moyen de Belgique. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 53, 1–10.Google Scholar
Fairon-Demaret, M., Hilton, J. & Berry, C. M. 1999. Surface preparation of macrofossils (dégagement). In Fossil Plants and Spores: Modern Techniques (eds Jones, T. P. & Rowe, N. P.), pp. 33–5. London: Geological Society.Google Scholar
Geng, B.-Y. 1992. Studies on Early Devonian flora of Sichuan. Acta Phytotaxonomica Sinica 30, 197–211.Google Scholar
Gensel, P. G. & Albright, V. M. 2006. Leclercqia complexa from the Early Devonian (Emsian) of northern New Brunswick, Canada. Review of Palaeobotany and Palynology 142, 103–21.CrossRefGoogle Scholar
Gensel, P. G. & Kasper, A. E. 2005. A new species of the Devonian lycopod genus, Leclercqia, from the Emsian of New Brunswick, Canada. Review of Palaeobotany and Palynology 137, 105–23.CrossRefGoogle Scholar
Gothan, W. 1921. Potonié's Lehrbuch der Paläobotanik, 2nd ed. Berlin: Verlag von Gebrüder Borntraeger.Google Scholar
Grierson, J. D. & Banks, H. P. 1963. Lycopods of the Devonian of New York State. Palaeontographica Americana 4, 220–95.Google Scholar
Grierson, J. D. & Banks, H. P. 1983. A new genus of lycopods from the Devonian of New York State. Botanical Journal of the Linnean Society 86, 81–101.CrossRefGoogle Scholar
Halle, T. G. 1936. On Drepanophycus, Protolepidodendron and Protopteridium, with notes on the Palaeozoic Flora of Yunnan. Palaeontologica Sinica A 1, 1–38.Google Scholar
Jurina, A. 1988. The Middle and Late Devonian flora of North Eurasia. SSSR Academy of Sciences Transaction of Palaeontology Institute 227, 1–175 (in Russian).Google Scholar
Kenrick, P. & Crane, P. R. 1997. The Origin and Early Diversification of Land Plants, a Cladistic Study. Washington, London: Smithsonian Institution Press. 441p.Google Scholar
Li, C.-S. 1990. Minarodendron cathaysiense (gen. et comb. nov.), a lycopod from the late Middle Devonian of Yunnan, China. Palaeontographica B 220, 97–117.Google Scholar
Liao, W.-H. & Ruan, Y.-P. 1995. Devonian stratigraphy and palaeogeographical outline. In Stratigraphy, Palaeogeography and Tectonics of Northwest China (eds Zhou, Z.-Y. & Lin, H.-L.), pp. 117–47. Nanjing, China: Nanjing University Press (in Chinese with English abstract).Google Scholar
Meyer-Berthaud, B., Fairon-Demaret, M., Steemans, P., Talent, J. & Gerrienne, P. 2003. The plant Leclercqia (Lycopsida) in Gondwana: implications for reconstructing Middle Devonian palaeogeography. Geological Magazine 140, 119–30.CrossRefGoogle Scholar
Ouyang, S. 1984. Microfossils from the Devonian Heitai Formation of Mishan County, Heilongjiang Province. Acta Palaeontologica Sinica 23, 69–84 (in Chinese with English abstract).Google Scholar
Richardson, J. B., Bonamo, P. M. & McGregor, D. C. 1993. The spores of Leclercqia and the dispersed spore morphon Acinosporites lindlarensis Riegel: a case of gradualistic evolution. Bulletin of the Natural History Museum, London (Geology) 49, 121–55.Google Scholar
Schweitzer, H. J. & Cai, C.-Y. 1987. Beiträge zur Mitteldevon-Flora Südchinas. Palaeontographica B 207, 1–109.Google Scholar
Scotese, C. R. & McKerrow, W. S. 1990. Revised world maps and introduction. Geological Society of London, Memoirs 12, 75–85.CrossRefGoogle Scholar
Sze, H.-C. 1960. On some Devonian plants from the Dzuangaria Basin. Acta Palaeontologica Sinica 8, 205–16 (in Chinese with English abstract).Google Scholar
Sze, H.-C. 1961. On some Devonian plants from the Dzuangaria Basin, northwestern Sinkiang. Scientia Sinica 10, 209–32.Google Scholar
Torsvik, T. H. & Cocks, L. R. M. 2004. Earth geography from 400 to 250 Ma: a palaeomagnetic, faunal and facies review. Journal of the Geological Society, London, 161, 555–72.CrossRefGoogle Scholar
Wang, D.-M. & Hao, S.-G. 1996. Report of Sawdonia in China, Sawdonia curstipa sp. nov. . Acta Botanica Sinica 38, 318–22 (in Chinese with English abstract).Google Scholar
Wang, Y., Berry, C. M., Hao, S.-G., Xu, H.-H. & Fu, Q. 2007. The Xichong flora of Yunnan, China: diversity in late Mid Devonian plant assemblages. Geological Journal 42, 1–12.Google Scholar
Wang, Y., Xu, H.-H., Fu, Q. & Tang, P. 2004. A new diminutive plant from the Hujiersite Formation (late Middle Devonian) of North Xinjiang, China. Acta Palaeontologica Sinica 43, 461–71.Google Scholar
Xu, H.-H. & Wang, Q. in press. On the correct name for the Middle Devonian herbaceous lycopsid Protolepidodendron (Protolepidodendraceae, Lycopsida). Acta Palaeontologica Sinica.Google Scholar
Xu, H.-H., Wang, Y., Berry, C. M. & Cai, C.-Y. in press. Two species of Haskinsia Grierson et Banks (Lycopsida) from the Middle Devonian of Xinjiang, China, and their palaeogeographical considerations. Botanical Journal of the Linnean Society.Google Scholar
Figure 0

Figure 1. Generalized geological and geographical map showing probable localities of Sze's (1960, 1961) collection in Xinjiang, NW China, and the relative generalized position of the Yunnan Middle Devonian flora.

Figure 1

Figure 2. Leclercqia cf. L. complexa from the Middle Devonian of North Xinjiang, China. (a) New discovered short leafy stem on the reverse side of PB3246 (Sze, 1960, 1961). (b) Enlargement of leaves in Sze's unprepared specimen PB3247, upper leaf partially prepared, four segments visible distally (arrow); lower unprepared leaf shows typical bifurcation as observed in Protolepidodendron scharyanum Kräusel et Weyland. (c, d) Stages of serial dégagement to the leaf 2 in (a). Lettering of segments follows Fairon-Demaret (1980). All scale bars = 1mm.

Figure 2

Figure 3. Leclercqia cf. L. complexa from the Middle Devonian of North Xinjiang, China. Line drawings of leaves in Figure 2. (a) Arrowed leaf in Figure 2b; (b,c,d) correspond to leaves 5, 4 and 3 in Figure 2a; (e,f,g) three stages of serial dégagement to the leaf 2 in Figure 2a (f and g correspond to Fig. 2c and d). Lettering of segments follows Fairon-Demaret (1980). Scale bar = 2mm.