XXXIX] PSETJDOCYCAS 561 



against drought is afforded by 'other means than those usual 

 among existing Cycads,' which provide against excessive transpira- 

 tion by the sinking of the individual stomata below the surface. 

 The epidermal features of Pseudocycas afford a striking example 

 of the danger of basing conclusions on mere impressions and they 

 further emphasise the great difference between Mesozoic Cycadean 

 fronds and those of recent genera. 



We have no knowledge of the nature of the reproductive organs 

 of the plants which bore Pseudocycas fronds, but the agreement 

 of the stomata and epidermal cells with those in some Bennettita- 

 lean types favours the inclusion of the genus in that class. It 

 has previously been pointed out that the impression figured by 

 Heer^ in close association with the Greenland specimens of Pseudo- 

 cycas Steenstrupi as a carpellar.y leaf of the Cycas type is much 

 too imperfect to be identified and has no claim, as an examination 

 of the actual specimen in the Copenhagen Museum convinced me, 

 to be compared with a megasporophyll of Cycas. This view is 

 shared by Nathorst. 



In some cases the name Cycadites has been applied to fragments 

 that might equally well belong to Conifers or other plants, and 

 not infrequently a careful examination of fossils referred to 

 Cycadites shows that the pinnae afford no evidence of a true midrib. 

 Casts of revolute pinnae like those of the recent species Encepha- 

 lartos Ghellinckii (fig. 382) would present an appearance closely 

 resembling a strong midrib. Heer's Siberian Jurassic species 

 Cycadites sibiricus^ is probably a piece of a Tasniopteris or Nilssonia 

 frond, and C. gramineus Heer^ should be referred to Taxites. An 

 examination of the Indian fronds described by Oldham and Morris 

 and Feistmantel as species of Cycadites leads me to discard all 

 of them as trustworthy records of the genus : in Cycadites confertus* 

 and C. Blandfordianus^ there appear to be several veins in the 

 pinnae and not a single midrib. Cycadites constrictus^ is almost 



1 Heer (82) B. PI. v. 



2 Ibid. (78) ii. PI. iv. fig. 1 ; Nathorst (97^) p. 387. 

 » Heer (77) ii. Pis. vin., xxin., xxv. 



« Oldham and Morris (63) B. Pis. vn., vin. ; Feistmantel (77^) PL xLvra. fig. 1 ; 

 the drawing is very inaccurate. 



' Oldham and Morris (63) B. PI. ix. 



« Feistmantel (79) PI. vn. fig. 10; Nathorst (09) p. 5, note 2. 



s. in 36 



