224 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Bryophyta. 



(By A. Gepp.) 



Inter-relationships of the Bryophyta.* — F. Cavers discusses the 

 Anthocerotales. He gives an account of the morphology and anatomy 

 of Anthoceros, and describes the development of the reproductive organs 

 and of the sporogonium, and the characters of the mature sporogonium. 

 He then shows in what respect the allied genera, De/idroceros, Notothylas, 

 and Megaceros, differ from Anthoceros and from one another. As to the 

 systematic position which the Anthocerotales should occupy, he cites 

 M. A. Howe's summary of the characters wdiich are held to mark off the 

 Anthocerotales from the remaining hepaticae ; but he considers that the 

 significance of these characters has been much exaggerated, leading to a 

 deal of doubtful speculation regarding the relationships of the Arche- 

 goniatas and the origin of thePteridophyta. He discusses the said cha- 

 racters one by one, and shows them to be less distinctive than they at 

 first appear to be. The Anthocerotales probably have arisen from forms 

 like the Sphaerocarpales ; they have retained a meristematic zone at the 

 base of the sporogonium, and tbeir antheridia, originally exogenous, 

 have become endogenous ; the formation of antheridial groups is of 

 secondary importance. The characters which distinguish the Antho- 

 cerotean sporogonium are more or less definitely correlated with the per- 

 sistence of the basal meristematic tissue, and are connected with the 

 nutrition of the spores. The maturing spore-tissue situated above the 

 meristem is cut off from the mother-plant : hence supplies have to be 

 manufactured by the sporogonium itself, and this latter is therefore 

 elaborately equipped for a sub-independent life. 



Amphigastrial Antheridia in some Ptilidioid Hepaticae.f — V. 

 Schiffner publishes the results of his investigations of amphigastrial 

 antheridia and of the structure of the androecia of the Ptilidioideae. 

 He takes exception to Leitgeb's dictum that in the fobose Junger- 

 mannieaB the formation of antheridia is exclusively confined to the 

 lateral segments ; that it is always the dorsal half of the segment which 

 forms the antheridia. Schiffner finds that : — 1. In the Ptilidioideae 

 nearly all the species are dioecious (the exception being Anthelia Juratz- 

 Jcana). 2. The androecia of the group show great morphological varia- 

 bility, but in a given genus there is a certain uniformity which affords a 

 good systematic character, a very important point in this group of rather 

 ill-defined genera. 8. The androecia mostly occupy an intercalary 

 position on the shoot, that is, typically the male branch bears at its base 

 sterile leaf -organs and continues its apical growth vegetatively. 4. 

 The perigonial leaves and auiphigastria resemble the sterile leaves, 

 but differ in the larger undivided limbus and in the hollowed pocket 

 in which the antheridia are sheltered. 5. In many species with fila- 

 mentous leaf-segments protection against desiccation is provided by the 

 hair-like felt which gathers moisture by capillary attraction ; but even 

 in such cases as Trichocolea and Blepharostoma the limbus of the 

 perigonial bracts is more strongly developed than in the sterile leaves. 



* New Phytologist, ix. (1910) pp. 341-53. 

 t Hedwigia, 1. (1911) pp. 146-62 (figs.). 



