No. 551] 



NOTES AND LITERATURE 



beginning with Lophozia, leads through Sphenolobus to the great 

 family Lejeuniaceas, and to the characteristic genera Porella and 

 Frullania, which may be considered to represent the most per- 

 fectly developed characters of the whole order. 



The Anthocerotales 



The Anthocerotales, Cavers 's fifth order of Hepaticse, com- 

 prise a comparatively small number of liverworts of very 

 peculiar structure, and very readily distinguished from all other 

 plants. The differences between them and the other liverworts 

 are so marked that they are sometimes considered a class — Antho- 

 cerotes— coordinate, on the one hand, with all the other liver- 

 worts, on the other with the true mosses. 



The structures of the four genera which are comprised in the 

 order are so much alike that they can all be assigned without 

 question to a single family, Anthocerotacea?. 



The gametophyte is of simple structure, and all the cells much 

 alike, each as a rule containing a single large chromatophore 

 resembling that of many green algffi. The reproductive organs, 

 both archegonia and antheridia, show certain peculiarities, which 

 in some ways have their nearest approximation among the lower 

 ferns, and in connection with the characters of the sporophyte 

 suggest a real connection between the ferns and the Antho- 

 cerotalea. 



The sporophyte differs much from that of the other liverworts. 

 In all of the' Anthocerotacea, except possibly some species of 

 Notothylas, the spore-producing tissue all arises from the outer 

 region (amphithecium) formed by the first periclinal divisions 

 in the capsule, and much the greater part of the tissue of the 

 sporophyte remains sterile. In all cases a large foot is present, 

 and above it a zone of actively dividing cells is present, which 

 may retain its activity for several months, so that the sporophyte 

 may attain a length of 10 centimeters or more. As the outer 

 tissues are in most cases well provided with chlorophyll, and 

 sometimes with stomata, a complete photosynthetic apparatus 

 is established much in advance of anything found in the other 

 Hepaticae. 



This long-continued growth of the sporophyte is associated 

 with a central strand of conducting tissue (columella), which is 

 reminiscent of the axial vascular bundle of the young sporo- 



