148 



MORPHOLOGY OF SPERM ATOPIIYTKS 



We have described the strohihis 

 of Cycndeoidea Dacotensis as consist- 

 ing (if a slieath of ovei-hipping Lracts, 

 within which niicrosporophylls liear- 

 ing Marattialike synangia occur. 

 Witliiu the niicrosporophylls, and 

 towards the hase id' the strohilus, 

 there is discovered what at first 

 sigiit apjieai's to he merely the conic- 

 al apex (>i tlie axis of the strohilus, 

 l)Ut whi(di proves to he the ovulate 

 region (Fig. 104). The conical re- 



FiG 10^ — C t/caihotdea JJacoUn.^i^^ 



a very wmall part of a sonic- . i m • i i 



wi.at" tangential longitudinal ceptacle IS covered all over with tlK 



scftiijn of a .'^trobilus, to show 

 in side view the septa of a s}n- 



anLnuin, x S. — From prepara- 

 tion made by (r. E. Wielanh 

 from speeimen lu Yale Uni\'er- 

 sitv Museum. 



characteristic stalked seeds and " in- 

 terseiiiinal scales." In this case the 

 " receptacle "' really resembles an 

 axis, and is of the ordinary Gymno- 

 sperm type; while in BrniteU itcs 



and certain species of Cijcadeoidea the receptacle is flattened. 



This elongated ovulate axis is not always associated with a hi- 



sporangiate strohilus, as it occurs in strictly ovulate strobili. 



In Fig. 105 there is 



shown a transverse 



section (if a young 



ovulate stroliilus of 



Cycadeo idea colossa I- 



is, wdiose axis is of 



the elongated type, as 



in the hisporangiate 



C. Darohnsis ( Fig. 



101), l)ut wliicli is 



invested directly by 



the ensheathing ster- 

 ile bracts. The illus- 



tratidu alsd sIkiws 



some of the cliaracter- 



istic ramenta which 



were packed between 



the siqierhcial sheath 



and the oviilifi'r(.ius 



Fio. 104.— rycd,/, "o/iK /laror'rwsjs, li.iiL'itudinal seetiou 

 through basal portion of slrobilus, sliowini;- at tlie 

 left portions ol' synani:ium-e.>vei-ed spuroj.ln lis. and 

 at the rielit the owilale region otthe strobilus, \ 4. 

 — Fr.im preiiaration nneli' by C. IJ. \V iel.\nii from 

 s]ieeimen in Yale bniversity Museum. 



