832 RECORD OF CURRENT RESEARCHES RELATING TO 



determined by the author to be a male specimen of a Monoclea, and 

 this is also the case with specimens in herbaria bearing this name. 

 Professor Leitgeb is in doubt whether D. dilatata has any existence at 

 all, and whether all specimens so named do not belong to a hitherto 

 undescribed species of Monoclea, which should be called M. dilatata; 

 belonging therefore not to the Marchantiaceae, but to the Jungerman- 

 niacesB. 



Formation of the Sporogonium of Archidium.* — This genus of 

 mosses is of special interest as presenting a point of contact between 

 the Phascacese and Bryineae, and at the same time exhibiting points 

 of resemblance to the Hepaticae. Professor Leitgeb has made the 

 structure and mode of formation of the sporogonium a subject of 

 special study. 



The author regards the sporogonium of all Musci (including 

 Sphagnaceae) as consisting, in its earliest stage of development, of 

 an inner mass of cells, the endothecium, which is distinctly separated 

 from a peripheral mass, the amphithecium. According to the mode 

 in which the spores are developed, he distinguishes the following 

 types : — 



A. Spores formed from the amphithecium. 



1. Sphagnacece type. The endothecium produces only the 



columella, which however does not penetrate the 

 spore-forming layer, but is covered by it. 



B. Spores formed from the endothecium. The sporogonium 



always grows by means of a two-edged apical cell. 



2. Archidium type. Spore-forming and sterile cells are 



intermingled in the endothecium ; the spore-sac is 

 separated from the wall of the capsule by a bell- 

 shaped cavity. 



3. Andreceacece type. The endothecium is differentiated 



into a spore-forming layer and the columella which 

 does not penetrate the former. The innermost layer 

 of the amphithecium becomes the spore-sac, which 

 however is not separated from the wall of the capsule 

 by any cavity. 



4. Bryinece type. The endothecium is differentiated as 



in No. 3 ; but the columella penetrates the spore-sac, 

 which is sejjarated from the wall of the capsule by a 

 cylindrical cavity. 

 The following are the most noteworthy points in connection with 

 the development of the spores and sporogonium of Archidium : — 



1. In the first stages of the development of the sporogonium until 

 the differentiation of the amjihithecium and endothecium, Archidium 

 agrees with the other Phascaceae. 



2. The same is the case also with regard to the formation of the 

 outer spore-sac ; but this, as in the Andreaeacefe, covers the inner 

 tissue as a closed bell-shaped layer, and is separated from the wall of 

 the capsule by a cavity. 



* ' SB. k. k. Akad. Wiss. (Wien),' Ixxx. (1880) p. 447. 



