1 66 The Botanical Gazette, fJ une ' 



other. The lateral branches are all normal. This case is 

 quite typical for phenomena as shown by dichotomously 

 branching abnormal stems with opposite leaves. The small 

 letters indicate that the leaves are situated on the side of the 

 branch away from the observer, and these leaves are indicated 

 by dotted contours in the figures. 

 Heidelberg^ Germanv* 



A study of some anatomical characters of North American 



Graminese. I. 



THKO, HOLM. 



The genus Uniola. 



(with PLATE XV.) 



In the year 1810, when Brisseau-Mirbel said: 1 4t Le seul 

 moyen de perfectionner les families naturelles, est a joindre a 

 letude des caracteres botaniques, celle de tous les faits rela- 

 tifs a Tanatomie et a la physiologic,' ' he hardly thought of 

 the important change that would come about in systematic 

 botany. The rapid increase in the number of species known 

 made it evident that botanists must not content themselves 

 with the mere external characters, but that others should be 

 sought. Later appeared a series of researches especially by 

 French and German authors, wherein an attempt was made 

 to give anatomical diagnoses to a number of species; most 



successfully by Duval-Jouve, Radlkofer and Vesque. The 

 importance of studies of that kind was very clear; they not 

 only furnished additional and often even more reliable system- 

 atic characters, but they extended the study of anatomy into 

 wider fields than ever before, until anatomy has become one 

 of the most important modern lines of botanical science. 



And the study of internal structure gave also a most strik- 

 ing illustration of the physiological life; it became easy to 

 infer from the structure the conditions under which the plant 

 had lived, whether in dry or moist localities, exposed to the 

 sun or in deep shade, etc. Anatomy also rendered great help 

 in the discrimination of species, as shown for instance by 



2 Sur l'anatomie et la physiologie des plantes de la famille des Labiees. 

 (Ann. du Museum d'Hist Nat. vol. XV.) 



