274 Journal of Applied Microscopy. 



have been frequently studied, but Dendroceros, being exclusively tropical, has 

 been necessarily neglected, the only important account being that of Lietgeb, 

 who had only herbarium material to work with, and even this consisting mostly 

 of mature plants. While visiting Jamaica in the summer of 1897, Prof. Camp- 

 bell put up an abundant supply of material in chromic acid and in alcohol. The 

 plant is an epiphyte, growing upon twigs and stems of small trees and shrubs, 

 and also upon the upper surface of the leaves. A part of the summary is 

 about as follows : in its apical growth and form of the thallus, Dendroceros differs 

 decidedly from the other genera of the order. The type of apical cell is that 

 found in Pc//ia and in the homasporous ferns, especially Osniiinda. The 

 abnormally large chloroplasts of O. cinnamomea may indicate a relationship 

 with forms like Dendroceros. The archegonium corresponds in structure 

 with those of Notothylas and Ant/ioceros, and is intermediate in character 

 between these. The antheridium is solitary and is endogenous in origin. The 

 tirst wall in the embryo is longitudinal, as in Antkoceros, but the first transverse 

 wall determines the limit of the foot, as in Notothylas. The archesporium comes 

 from the amphithecium as in the other two genera. The division of archesporial 

 cells into sporogenous and sterile ones is less regular than in the other genera, 

 and primary archesporial cells may become sporogenous ones without further 

 divisions. The elaters have a thickened spiral band. In D. crispus (?) the 

 spores germinate within the capsule. No stomata were found on the capsule. 

 Dendroceros shows a close relation to Anthoceros. In the form of the archegon- 

 ium and in the early stages of the embryo, Dendroceros is intermediate between 

 Notothylas and Anthoceros. Two excellent plates illustrate the development of 

 the thallus, archegonium, antheridium, and sporophyte. c. j. c. 



^ . „ „ ,^ „ , , , Prof. Campbell takes exception to 



Campbell, I), n. Recent work upon the de- ^ ^ 



velopment of the Archegonium. Bot. Gaz. Gayet's work on the development of 

 26: 428-431, 1898. ^]-^g archegonium in the liverworts and 



mosses. (Gayet's work appeared in the Ann. d. Sci. Nat. Bot. VIII. 3: 161-258, 

 1897, and was reviewed in the Bot. Gaz. 25: 68-69, 1898.) The prevalent 

 opinion is that in mosses the growth of the archegonium is largely apical, while 

 in liverworts it is for the most part intercalary, the early division of the " cover 

 cell " in liverworts preventing additions to the neck from this source. Gayet 

 claims that the terminal cell, often called the cover cell, contributes to the 

 growth of the neck of the archegonium in liverworts as well as in mosses. 

 Gayet also claims that neck canal cells in mosses are not cut off from the base 

 of an apical cell, as is generally supposed, but have the same origin as in liver- 

 worts. This means that he regards the type of archegonium as essentially the 

 same in liverworts and mosses. 



In his book on Mosses and Ferns, Prof. Campbell showed that there is an 

 essential difference between the development of the liverwort archegonium and 

 that of the moss, the cover cell of the liverworts very early undergoing the 

 quadrant division and thus becoming incapable of functioning as an apical cell, 

 while in the moss the apical cell persists for a long time and contributes both to 

 neck cells and the neck canal cells. In regard to the liverworts the present 

 paper gives convincing evidence in favor of the view already expressed by the 



