Morphologie, Teratologie, Befruchtung, Cytologie. 99 



the cup, therefore, is merely that of a remarkably unified colony 

 of gametophores. 



Triple cell fusions were observed in P. Claytoniata and P. Violae, 

 and trinucleated accidiospores were frequently found in both of 

 these species and in Ur. Caladi'i. Several quadrinucleated aecidio- 

 spores and a chain of quadrinucleated cells were found in P. 

 Claytoniata. 



The first fusion cells are formed at the center of the gametic 

 tissue and the subsequent ones are formed on all sides ofthis center 

 in centrifugal order, until the lateral borders of the aecidium are 

 reached. 



The fusing cells may have their long axes in general in the 

 long axis of the cup for example P. Claytoniata, P. Violae, P. Hy- 

 drocotyles and Ur. Caladi'i, or tangential to its surved basal surface, 

 for example P. Eatoniae. 



The presence or absence of a peridium is a natural but not 

 very fundamental distinction between the aecidium cup and the 

 cacoma. The production of a peridium is correlated vvith the deep 

 location of the cup and the extensive formation of sterile cells. 



As has long been known, the peridial cells are metamorphosed 

 aecidiospores and aecidiospore initial cells. The central arch of the 

 peridium is formed from the apical aecidiospores of the inferior 

 spore chains and the lateral walls from entire peripheral spore 

 chains. The first peridial cells are produced at the center of the 

 arch and the peridium enlarges from this point centrifugally until 

 the bases of the lateral walls are reached. Its subsequent enlarge- 

 ment is b}^ the basipetal growth and sterilization of the peripheral 

 spore chains. M. J. Sirks (Haarlem). 



Mattoon, W. R., Life History ofShortleafPine. (U. S. Dept. 

 Agricult. Bull. 244. July 21, 1915.) 



This bulletin describes the name and identification of Pinus 

 echinatiis Mill, its geographic and economic ränge, the character of 

 Stands, size, age , habit light requirements, reproduction, growth, 

 injury and yield. Harshberger. 



McAllister, F., The development ofthe embryosac in the 

 Convallariaceae. (ßotan. Gazette. LVIII. p. 137 — 153. 1914.) 



In the eight members of the Convallariaceae investigated by 

 the author, the embryosac is formed from one reduction nucleus in 

 Polygonatum, from 2 in Smilacina racemosa, S. amplexicaidis, and 

 Streptopus rosens, and from 4 in Smilacina stellata, S. sessifolia, 

 Maianthemum canadence and Medeola virginica. 



In all forms in which more than one reduction nucleus enters 

 into the structure of the embryosac. these nuclei are at first more 

 or less completely separated by cell membranes, the degree of 

 Separation varying from split cell plates in Smilacina stellata to 

 evanescent cell plates in Medeola virginica. 



The difference in the degree of the Separation of these cells 

 cannot affect their morphological Status; they are all megaspores. 



In the light of this evidence it seems reasonable to conclude 

 that all reduction nuclei arising from the nucleus of the megaspore 

 mother cell, whether temporarily separated or not separated at all, 

 should be regarded as megaspore nuclei. 



