﻿1903] BRIEFER ARTICLES 285 



I 



Hackel describes a second species of Craspedorhachis, C, Menyharihii, 

 Bull. Herb. Boiss. II. i: 770, igoi, from southeast Africa, in which the 

 flowering glume is only one-fourth to one-fifth shorter than the outer glumes, 

 thus making the difference less between our plant and the genus Craspedor- 

 hachis. — A. S. Hitchcock, Bureau of Plant Industry, U. S. Department of 

 Agriculture, 



THE MORPHOLOGY OF SPORE-PRODUCING MEMBERS. 



[In view of the fact that Professor Bower's last paper,^ which contains the general 

 conclusions from his studies of spore-producing members, is not likely to appear for 

 some time, we venture to publish in advance the following abstract of the memoir, which 

 was read before the Royal Society on February 12, 1903, and kindly communicated 



to us. — Eds.] 



This concluding memoir contains a general discussion of the 

 results acquired in the four previous parts of this series, and of their 

 bearing on a theory of sterilization in the sporophyte. The attempt 

 is made to build up the comparative morphology of the sporophyte from 

 below, by the study of its simpler types; the higher and more 

 specialized types are left out of account, except for occasional com- 

 i parison. It is assumed for the purposes of the discussion that alter- 



nation of generations in the Archegoniatae is of the antithetic type, 



and that apogamy and apospory are abnormalities, not of primary 

 origin. 



After a brief allusion to facts of sterilization in the sporogonia of 

 bryophytes the similar facts are summarized for the pteridophytes. 

 It has been found that examples of sterilization of potentially sporo- 

 genous cells are common also in vascular plants, while occasionally 

 cells which are normally sterile mav develop spores. Hence it is con- 

 cluded that spore-production in the archegoniate plants is not in all 

 cases strictly limited to, or defined by, preordained formative cells, or 

 cell-groups. A discussion of the archesporium follows, and though it 

 IS found that in all Pteridophyta the sporogenous tissue is ultimately 

 referable to the segmentation of a superficial cell, or cells, still in 

 them, and indeed in vascular plants at large, the segmentations which 

 lead up to the formation of spore mother cells are not comparable in 

 all cases; in fact, that there is no general law of segmentation under- 

 lying the existence of that cell or cells which a last analysis may mark 

 out as the ** archesporium "; nor do these ultimate parent cells give 

 nse in all cases to cognate products. Therefore it is concluded that 



'Bower, F. O., Studies in the morphology of spore-producing memhers. No. V. 

 General comparisons and conclusions. 



