58 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the formation of the perianth and the calyptra, which arise also from 

 the archegonium stalk or from the tissue of the stem itself, Cleistocarpic 

 mosses are retrogressions. Species exist in which the spores grow out 

 into cells even in the capsule {Gleistostoma, Dicuemonacefe). E. S. G. 



Air Chambers of Grimaldia fragrans.— Alexander W. Evans 

 {Bull. Torrey Bot. Club, 1918, 45, 235-251, 14 figs.). The thalline 

 structure of most Marchantiales may, with reference to the air-chambers, 

 be classed under three distinct types, represented respectively by Riccia, 

 Beioulia and 3Iarchantia. Grimaldia is of the Reboulia type. 1. The 

 air-chambers of G.fragrans are in several layers in the thickened median 

 portion of the thallus. 2. The dorsal chambers communicate with the 

 outside by means of epidermal pores. They are subdivided by a regular 

 system of more or less vertical, united cell-plates, enclosing narrow 

 spaces, so that the boundaries of the chambers are difficult to distinguish. 

 The cell-plates sometimes reach the epidermis and sometimes do not j 

 in the latter case the free margins sometimes bear scattered teeth, less 

 than two cells in length, especially in the vicinity of the pores. Except 

 for these teeth the chambers lack filaments completely. 3. The more 

 deeply situated chambers communicate with one another and with the 

 dorsal chambers by means of passage-ways ; they are scarcely or not at 

 all subdivided by cell-plates. 4. The chambers all owe their origin to 

 a splitting of cell-walls in closely united tissue. In the case of the 

 dorsal chambers, the split sometimes begins below the surface and 

 extends outward ; sometimes at the surface and extends inward. 5. The 

 dorsal chambers appear first, very close to the apical cell, but the more 

 deeply situated chambers appear soon afterwards. 6. The increase in 

 the size of the chambers is due largely to the growth of the bounding 

 cells, and only slightly to further splittings of cell-walls. The system 

 of united cell-plates in the dorsal chambers and the partitions between 

 the chambers increase in vertical height simultaneously. Direct out- 

 growths from the surfaces of cell-plates play a very small part in the 

 process of subdivision. A. G. 



Mixtures of Species among the CephaloziellaceaB. — Ch. Douin 

 {Revue Bryologique., 1914, 41, 1-8, 17-26, 1 pi.). A discussion of the 

 intermixing of species of Cephaloziella in their natural growth, their 

 similar aspect, and the difficulty thus entailed in discriminating these 

 small species, the nature of the inflorescence of which is hard to ascer- 

 tain. Species normally without amphigastria produce them on their 

 propaguliferous stems. Such amphigastria must be excluded as specific 

 characters. Treating of the errors of authors, Douin carefully dis- 

 tinguishes Evansia dentata (Raddi) Douin from Prionolohus Turneri 

 (Hook.) ; shows that the original specimen of Jungermamiia hyssacea 

 Roth contains a mixture of J. StarJcii Nees and J. Hampeana Nees ; that 

 that of Gephalozia myriantha Lindberg contains G. elegans Heeg and 

 G. Jackii Limpr. ; and that that of Gephalozia Limprichti Warnst. is 

 mixed with C. rubella (Nees). He criticizes G. Starkii var. examphi- 

 pastriata \ G. divaricata Spruce, an asylum for misunderstood specimens, 

 from which Douin extracts two new species — Gephaloziella ludoviciana 



