G42 DR. DICKSON ON DEVELOPMENT OF 



like projection. The process of dilatation or expansion commenced in this portion 

 of the corolla-tube progresses gradually until the period of flowering, by which 

 time the characteristic spur is fully developed. As in the calyx, the connation 

 of the parts of the corolla is unequal in extent, the anterior and lateral petals 

 forming an anterior lip, and the two posterior a posterior one. The aestivation of 

 the corolla is similar to that of the calyx — that is to say, the odd part (here, of 

 course, anterior) is overlapped by the lateral, which are overlapped by the other 

 two parts. 



Andrcechcm. 



In the adult condition, the androecium of Pinguicula consists of two stamens 

 placed anteriorly. The examination of the flower in its earlier stages, however, 

 reveals the interesting fact of the presence of two lateral rudiments or staminodes. 

 The two fertile stamens appear first — at least they may be seen as distinctly 

 present when the staminodes are as yet very indistinct, if not quite inappreciable. 

 Their appearance seems to follow that of the corolla in quick succession, from 

 the great difficulty I have experienced in finding flow T ers having the corolla dis- 

 tinctly visible, with at the same time no trace of the stamens. Indeed, even in 

 the stage represented in Plate XXVIII. fig. 4, although the stamens can scarcely be 

 said to be visible, yet, as I have already said, the slight indentation in the middle 

 line anteriorly may possibly be held as indicating, indirectly, the presence of a 

 staminal elevation on either side of it. 



The stamens originate as rather large protuberances, which very soon exhibit 

 an oblong figure, being wider from side to side than deep from without inwards. 

 They alternate with the petals, being superposed to the two anterior sepals. In 

 their further development there is nothing very special to be noted. As usual, 

 the anther is formed first, becoming raised upon the subsequently developed fila- 

 ment. The connective forms the great bulk of the young anther, and broadens 

 upwards in such a way that the four anther-cells lie upon its upper surface, what 

 correspond to lateral furrows forming a single transverse one across the top of the 

 anther. Ultimately the anther becomes one-celled, by the occurrence of absorp- 

 tion in the substance of the connective and consequent fusion of the anther-cells. 

 Dehiscence takes place at the transverse furrow just mentioned. 



The staminodes originate as mammillae of small size, compared with the 

 staminal rudiments, and are superposed to the lateral sepals. They are repre- 

 sented in different stages in Plate XXVIII. figs. 5-9. As a rule, they do not 

 proceed beyond the stage represented in fig. 7, and usually become wholly 

 obliterated by the disproportionate development of the neighbouring parts. 

 Sometimes, however, they are developed as shorter or longer styloid processes ; 

 and I have met with a good many instances where one or both presented a 

 terminal knob, or were even distinctly antheriferous ; in the best developed cases 



