20 



M. YOKOYAMA. 



species, forms which are also found in other localities ; viz., Omjchiop- 

 sis elongata, Asplenium whitbiense, A. argutulum, A. distans, and Podoza- 

 mites Pieinii, which are all very important Oolitic types. 



Among other interesting forms of the Japanese plants, I may 

 mention Nilssonia nipponensis m. closely akin to N. acuminata Schenk of 

 the Jihaetic, and Dioonites Kotoei m., and Equisctum ushimarense m., 

 resembling respectively Dioonites Brong?iiarti Schenk, and Eqtiisetum 

 Buchardti Schimp. of the Wealden. With the Infra- Liassic flora of 

 Tongking described by Zeiller, 34 ) we have no species in common, save 

 Podozamites distans , which Heer has shown 35 ) to be one of the many 

 forms of Podozamites lanceolatus. 



As seen from a foregoing table, 19 species or 89 °/ of the whole 

 plants are ferns, 15 species or 30% cycads, 10 species or 20 % coni- 

 fers, and the remaining 11 °/ are taken up by Rhizocarpeae, Equiseta- 

 ceae and Dubia. Therefore the ferns are the most numerous in the 

 Japanese flora, next to which come the cycads ; while conifers are 

 only half as numerous as ferns. In the Indian flora of Kach and 

 Jabalpur, whence indeed we at present know 48 species of plants, 

 40 % are cycads, 29 °/ ferns and 29 % conifers, thus showing a great 

 preponderance of cycads, over the two others. Again, a different 

 order holds in the great flora of Siberia. There, the two able 

 palaeophytologists Heer and Schmalhausen, have already discovered 

 127 species 36 ) of Jurassic plants. Of these, conifers take the lead, 

 making up about 40 °/ °f the whole flora ; while ferns and cycads 

 range a little above 20 °/ , the former perhaps a little more abundant 

 than the latter. Therefore our own flora may be considered as a 



34) Zeiller: — Examen de la flore fossile des couches de charbon du Tongking iu Annales des 

 Mines, 8 e Serie, tome II, 5 e livr., 1882. 



35) 0. Heer: — Beiträge zur Juraflora Ostsib. u, d. AmurL, 1876, p. 107. 



36)0. Heer: — Nachträge zur Juraflora Sibiriens p. 2 (Memoirs d. l'Acad. Imp. d. St. Peters, 

 bourg, Vile série, Tome XXVII, no. 10). Flora Fossilis Arctica, vol. VI. 



