174 



PEINCIPLES OF PLANT-TEBATOLOGT. 



tends to appear. In some semi-petaloid stamens of 

 a tulip such lobing was obvious and sucli secondary 

 formation of (petaloid) anther-loculi could be seen 

 (fig. 129), for an explanation of which the reader may 

 be referred to the paragraphs under " phyllody " 

 (see also the abnormal PolygonumAeai there described) . 

 The case, figured by Masters, of a petaloid stamen of 

 a violet with four lamellse on the upper surface, may 

 perhaps be explained as follows : that the two outer- 

 most lamellae correspond to the leaf -margins, and that, 



Fig. 130. — Ardbis alpina (Book Cress). Diagram of flower showing 

 petalody of all stamens, dimerous corolla { p), and proliferation (aa; 

 = axis) ; the two interior stamens of inner whorl {sfi) also fused 

 into one. (After Velenovsky.) 



as in the case of some carpels, where the ovules are 

 inserted some little distance away from what appears 

 to be the margin, an extension of the leaf-tissue 

 outwards beyond the real margin has occurred. The 

 ventral lamellae are homologous in nature with virescent 

 ovules. 



In the columbine (Aqidlegia) there are two kinds of 

 doubling : (1) in which the stamens become changed 

 into petaloid spurred nectaries, and (2) that already 

 mentioned in which stamens and petals become 

 changfed into sepal-like structures. Braun observed 

 the same dual type in Delphinium orientale, but here 

 none of the petaloid stamens was spurred. 



