CYCADALES I2i 



THE MEGASPORANGIXTM 



The ovulate strobili usually occur singly in the center of the 

 crown (fig. 112), but in Encephalartos and Macrozamia several are 

 frequently found and in other genera more than one appear occa- 

 sionally. Some of these strobili are the largest known, those of 

 Macrozamia Denisoni reaching a length of nearly a meter, with a 

 weight of 30 kg., while the ovoid cones of Encephalartos caffer may 

 weigh as much as 45 kg. (84). The massive strobilus of Dioon 

 spinulosum reaches a length of 50 cm., with a diameter of 23 cm. 

 and a weight of 14 kg. Occasionally, the slender strobilus of 

 Microcycas reaches a length of 94 cm. and a weight of 9 . 5 kg. (52). 

 In Ceratozamia a length of 26 cm. is extreme, and in the remaining 

 genera the cones are comparatively small, perhaps the smallest 

 being that of Zamia pygmaea, in which they may be less than 3 cm. 

 in length. The size and weight of the group of sporophyUs of 

 Cycas have not been reported. 



In all the genera except Cycas the megasporophylls are in com- 

 pact strobili. The first strobilus is terminal upon the primary axis, 

 while aU others terminate secondary axes, except in Encephalartos, 

 Macrozamia, and Bowenia, where all strobili are axillary. Pearson 

 (47) states that in Encephalartos Friderici-Guilielmi and in E. 

 AUensteinii there are three to six cones symmetrically arranged 

 around the apex, so that there is no sympodium, the vegetative apex 

 continuing the growth of the stem. In Cycas the sporophylls bear 

 considerable resemblance to the foliage leaves, and are arranged like 

 an ordinary crown of foliage leaves, with the bud for the next crown 

 in the center (fig. 113); hence the trunk of the ovulate plant of Cycas 

 is always a continuation of the primary axis, and never a sympodium 

 as in most other cycads, including the staminate plant of Cycas 

 itself, but also excepting cases in which cones have the axillary 

 position. It can hardly be doubted that the compact strobili are a 

 later development from the Cycas type. Occasionally, even in com- 

 pact strobili, the meristem, instead of producing the stunted sporo- 

 phylls which usually terminate the strobilus, produces sporophylls 

 resembling foliage leaves; and in Encephalartos Wieland (51) 

 figures a strobilus with transitions between the sporophylls and the 



