STUDIES IN THE MORPHOLOGY OF YUCCA GLAUCA 



Donald Folsom 



INTRODUCTION 



Yucca glauca — whose general appearance is shown in plates 

 XXVIII, XXXIV— was first described by Nuttall in 1813, and later 

 as Yucca augustifolia by Pursh in 1814.* A comprehensive dis- 

 cussion of the taxonomy and nomenclature of the Yucceae, a tribe 

 of the Lilaceae, has been given by Trelease.* An account of 

 the chemical nature of Yucca glauca was published by x\bbott in 

 1887.- The followang studies are based upon data and material 

 .secured in the sandhill region of Nebraska in June and July of 1912. 

 The ecological aspects of this region, in parts of which Yucca glauca 

 is very prominent, have been described by Pool.'^'^ The w^riter 

 is under obligations to Professor Pool for helpful suggestions and 

 aid in photography received while with him during the summer of 

 1912, and to Professors Clements, Rosendahl, and Butters, for sug- 

 gestions and advice received during the preparation of this paper. 



Technique 



Most of the material was obtained near the Forest Reserve, 

 Halsey, Nebraska ; some — immature seeds — near Hackberry Lake 

 in Cherry County. All of it was killed and fixed in a chrom-acetic 

 solution made up as follows : 



Chromic acid 2.5 grams 



Glacial acetic acid 10.0 cc. 



^^^ell water 1000.0 cc. 



This fixing fluid apparently did not combine the reagents in the 

 right proportion, for it often caused more or less plasmolysis in 



