20 



CYCADALES 



[CH. 



acuminate pinnae with entire, unevenly lobed, serrate, or pinnatifid margins. 

 Some leaflets are so deeply dissected as almost to justify the appellation pinnate. 

 Both entire and dissected leaflets may occur on one frond and the lower ones 

 may be stalked while the upper pinnae are sessile. The venation agrees 

 closely with that of the genus Taeniopteris 1 . 



Bowenia. The large fronds of this genus (fig. 391) are peculiar in being 

 bipinnate ; they may reach a length of 2 metres and have a long slender 

 petiole: the asymmetrical lamina of the segments, entire or deeply serrate, 

 is attached by a very short stalk; the veins branch dichotomously 2 and 



FIG. 391. Bowenia spectabilis, frond. (From the Encyclopaedia Britannica.) 



diverge slightly. Both entire and serrate pinnae may occur on the same 

 plant, but Chamberlain has revived Andre's specific term serrulata in preference 

 to the generally adopted designation for the serrate forms, B. spectabilis 

 var. serrata 3 . 



Reproductive shoots 4 ". In Cycas circinalis, C. Rumphii, and 

 other species the megasporophylls reach a considerable length and 

 bear several lateral ovules each of which may be as large as a 



1 Vol. ii. p. 485. 2 Lignier (94). 



3 Chamberlain (12 3 ). 



4 For information on the anatomy of reproductive shoots, see Thibout (96); 

 Scott (97); Worsdell (98); Matte (04). 



