160 



PRINCIPLES OF PLANT-TERATOLOGY. 



In a shoot of Acacia horrida, owing to the infection 

 of the twig by a fungus, Mcidium ornamentale, the 

 thorny stipules were stimulated by an inordinate flow 

 of nutriment to develop as green laminate leaves. A 

 form of TJlex europseus (var. inermis) has been described 

 which is entirely devoid of spines, which were, there- 

 fore, presumably replaced by leaves. 



There can be no doubt that all these cases are due 

 to reversion to the primitive condition. 



7. Bracteody of Glands. — Velenovsky observed the 

 gradual transformation (by means of division, along 

 with displacement and enlargement of the products) 



Fig. 43. — a. Abnormal flower of Salix aurita. b. Normal flower of the 

 same. c. Female flower of Myrica cerifera. (After Velenovsky.) 



of the normal posterior gland in the flower of the 

 withe-tree (Salix aurita) into two transversely-placed 

 scale-like bracteoles (fig. 43). This is a reversion, 

 for in the Juglandaceee and the female flower of 

 Myricaceee (to which order Salicacese are closely allied) 

 these two bracteoles occur as a normal feature. In 

 the course of evolution of the modern $ai^-flower 

 they have become not only fused together into a single 

 organ occupying a median posterior position, but also 

 reduced to a glandular structure. 



8. Petalody of Scale-lfaves. — A very remarkable 

 abnormality has recently been described by Miss M. L. 

 Green, and which the writer had the pleasure of inves- 

 tigating with her. It consisted in the partial prolife- 

 ration and transformation of some of the bulbils of a 

 tiger-lily (Liliurn tigrinum var. Fortunei) directly into 



