78 



PRINCIPLES OF PLANT-TERATOLOGY. 



figures a flower of Olarkia in which division of the 

 rudiment is rather late in appearing (similar in this 

 respect probably to Matthiola), so that, instead of a 

 number of separate equal petals being formed, the 

 rudiment branches fore and aft into a number of sub- 

 sidiary petals which in their turn branch or divide 

 collaterally ; so that the doubling in this flower is 

 caused by the presence of a number of groups or 

 bundles of petals. 



This mode of "doubling" of the corolla by dedouble- 

 ment, or by elongation of the axis and the independent 

 formation of new petal-rudiments at the apex, must be 

 held to be distinct from the " doubling " caused by 

 petalody of the members of other whorls of the flower, 

 a phenomenon to be considered in its proper place. 



(3) Andrcecium. 



Goebel found that in " double " flowers of Petunia 

 there was a larger number of stamens present than 

 the normal five, in one flower as many as twelve. In 

 the flowers of this plant (PI. XXXVII, fig. 3) as of 

 some others, e. g. Primula sinensis, Dianthus (fig. 92), 

 "doubling" is caused by division of the staminal 

 rudiments and subsequent petalody of some or all of 

 the products. In Silene peiidula it was the rudiments 

 of the inner whorl only which thus divided. This kind 

 of division would, of course, be in the antero-posterior 

 plane or serial, concerned as it is with the formation 

 of fresh whorls. 



In the genus Primula the five stamens are adnate 

 to and opposite the petals, an arrangement which is 

 anomalous, infringing the law of alternation, and which 

 must somehow be explained. In the early stages it 

 can be seen, as Duchartre and Pfeffer well showed, that 

 the stamen-rudiment develops first and that of the 

 petal somewhat later as a dorsal appendage thereof, a 

 fact which led these authors to evade the difficulty 

 above-mentioned by supposing that stamen and petal 



