230 PRINCIPLES OF Pr.ANT-TBRATOLOGy. 



WoESDELL. — " The Structure and Morphology of the ' Ovule ' : 

 an Historical Sketch." Ann. Bot., vol. xviii (1904), pp. 

 57-86. 



Wydlie. — "tjber Verdoppelang der Blattspreite." Flora, 

 Jahrg. XXXV (1852), pp. 737-743, pi. ix. 



ZiMMEEMANN. — " Hormaphroditismus und Sexualtransmuta- 

 tion. (Abnoraisexuelles Verhalten von Weiden.)" All- 

 gem. Bot. Zeitschr., Jahrg. xvii (1911), pp. 49-56, pi. i. 



ZwEiGELT. — "Was sind die Phyllokladien der Asparageen ?" 

 (Ester, bot. Zeitschr., Jahrg. Ixiii (1913), pp. 313, 408. 



II. SIMPLIFICATION. 



As the normal course of evolution has proceeded in 

 the direction of simplication, we might expect what 

 we find to be true, that abnormalities coming under 

 this heading are very much rarer than those occurring 

 under the former one. In fact, all these abnormal 

 structures embody changes which are, for the most 

 part, distinctly in the direction in which evolution 

 appears to be at present tending. 



1. ABBREVIATION. 



This is the opposite condition of proliferation. In- 

 stead of floral or inflorescence-axes being abnormally 

 elongated or present where they do not usually occur, 

 they are abnormally shortened or else completely 

 absent where they usually occur. 



1. The Inflorhscence. — In the lady's-smock {Gar- 

 damine pratensis var. acanlis) the internodes of the 

 axis have become suppressed, and the long-stalked 

 flowers arise from the axil of a leaf of the radical 

 rosette. This feature, however, is merely a reproduc- 

 tion of what occurs as the normal character in the 

 genera lonopsidium and Morisia, etc. 



Wirtgen describes an interesting case of this sort in 

 Oagea arvensis in which the flower-scape was entirely 

 suppressed and the flowers arose from the axils of the 

 bulb-scales or from bulbils produced in those axils. 



