XLV] WALCHIA 281 



(fig. 745) are characterised by the more or less oblique insertion of 

 the slender branchlets and by the comparatively long, narrow, 

 falcate, decurrent leaves. The ovoid or cylindrical megastrobili 

 terminal on the ultimate shoots bear imbricate ovate-lanceolate 

 sporophylls, but their preservation is not sucl^as to throw any 

 light on the structure of the seed-bearing organs. Zeiller^ mentions 

 a cone from Lodeve (Permian) 10 cm. long and 1 — 1*2 cm. in 

 diameter, but the average length is less than this. A branch 

 figured by Potonie^ from the Permian of Thuringia shows elliptical 

 leaf -cushions very like those on the larger stem described by 

 Mougeot as Araucarites valdajolensis. Potonie has drawn atten- 

 tion to the difiiculty of distinguishing small specimens of this 

 species from W. filiciformis and W. linearifolia, and some forms 

 described as W. imbricata and W. hypnoides are by no means 

 clearly distinguished from W. piniformis. In W. filiciformis 

 (Schloth.) the leaves are characterised by the downward curve of 

 the lamina near the base though this in itself is hardly a decisive 

 criterion. In W. linearifolia Goepp. the leaves are rather more 

 delicate and less falcate, while in W. imbricata they are usually 

 shorter, relatively broader, and more strongly imbricate and 

 incurved. W. hypnoides (Brongn.) is a smaller form though, as 

 Kidston* suggests, this may not be a specific character. Renault's 

 species W. fertilis* represents a similar form but with smaller 

 leaves, and each branchlet ends in a long and narrow strobilus 

 which affords no indication of the nature of the sporophylls. 



WalcJiia filiciformis (Schlotheim). 



This species, recorded from Permian and Stephanian beds, and 

 differing but slightly from W. piniformis is important as supplying 

 more satisfactory evidence as to the nature of the megastrobili. 

 Zeiller^ has described a fertile specimen from the Permian of 

 Brive in which the ovate-lanceolate cone-scales (sporophylls) bear 

 on their upper concave face single ovoid seeds, 7 — 8 mm. long. 

 The strobili appear to be lax in the arrangement of the monospermic 

 sporophylls. 



1 Zeiller (06) B. p. 204, Pl. L. figs. 3, 5; Bergeron (84). 



2 Potonie (93) A. p. 218. ^ Kidston (86) A. p. 15. 

 » Renault (96) A. p. 359; (93) A. PI. Lxxx. fig. 2. 



= Zeiller (92) A. p. 99, PI. XV. fig. 3. 



