The Ohio TSl^aturalisty 



PUBLISHED BY 



The Biological Club of the Ohio Stale Uni'versiiy, 



Volume VII. NOVEMBER. 1906. No. 1. 



TABLE OF CONTENTS 



SCHAFFNER, M ABEL— The Embryology of the Shepherd's Purse 1 



Bruner— Some Guatemalan Orthoptera, with Descriptions of Five Xew Species 9 



Caudell — List of Orthoptera Collected in Guatemala by C. C. Deam and E. B. Williamson 14 



Hambleton— Key to the Families of Ohio Lichens 14 



McCleery— Pubescence and Other External Peculiarities of Ohio Plants 16 



News and Notes 18 



Hyde— Meeting of the Biological Club 18 



THE EMBRYOLOGY OF THE SHEPHERD'S PURSE.* 



(A Posthumous Paper.) 

 Mabel Schaffxer. 



The embryo of the shepherd's purse {Bursa bursa- pastor is 

 (L. ) Britt.) has had an important place as a representative dicotyl 

 in most botanical textbooks. The original investigations of 

 Hanstein (1 ) and Famintzin (2) were superior and epoch-making 

 for their day, yet many points were left obscure and some of 

 these are still unsettled, as a reference to the various botanical 

 textbooks will show. Considerable variation has been reported 

 as to the succession of the cell divisions and other minor details. 

 The best recent account is by Coulter and Chamberlain (4, 5), 

 and what is given below is practically a confirmation of their re- 

 port with a few differences in details. 



The embryology of Alyssum as given by Miss Riddle (3) 

 shows several interesting deviations from the Bursa type and 

 makes it clear that generalizations can not be made without full 

 knowledge even in the case of closely related plants. 



It was my intention to make a complete study of the embryo 

 of Bursa and to prepare a series of drawings on the same scale 

 of magnification in order that not only the succession of cell divi- 

 sions and the development of the several embryonic tissues would 

 be apparent but also the actual increase in size of the embryo as 

 a whole and of the cells at various stages of development. 



The ordinary methods of killing and imbedding were employed 

 and the serial sections, cut 10-12 mic. thick, were stained on the 

 slide. Delafield's haematoxylin makes a very satisfactory stain 

 if properly employed. 



* Contribittions frcm the Botanical Laboratorv of the (Ihio State 

 Univirdtv, XXV. 



