42 



LAWS OF FLORAL STRUCTURE 



the flower stands opposite a sinus of the adjacent outer and inner circles. 

 Thus, in Fig. 44, the stamens of the circle nearest the corolla-lobes 

 alternate with the latter, while those of the next circle alternate with 

 the former and are consequently opposite to the corolla-lobes. In Fig. 

 43 the same relation can be observed between the other circles. It is 

 thus clear that the parts of two alternating circles, as of the first and 

 third, or the second and fourth, must stand opposite each other, or in 

 the same radial line. 



Anteposition Resulting from Suppressioji. — It is also clear that if 

 two circles shall be brought into juxtaposition by the suppression of 

 an intervening circle, their parts will naturally stand opposed and thus 

 appear to invalidate our second law, as in the case of the stamens and 



"Vi>^. 



J7 



Figs. 49 to 53. Figures illustrating torsion. 



petals of Claytonia (Figs. 45 and 40), where the stamen-circle originally 

 standing between the other one and the corolla has been suppressed. 

 Organs thus placed, the one directly in front of the other, are called 

 anteposed. 



Note should also be taken of the fact, already pointed out, that the 

 cluster of organs produced by chorisis corresponds in position with the 

 single part by the modification of which it was produced. 



Position Sometimes Obscured. — In examining the position of parts 

 great care should be taken by the student to see the actual point of 

 insertion, as the free portion of an organ frequently deviates from the 

 line of its true position and leads to error. 



Torsion. — One such condition which can easily lead to error is 

 Torsion, or twisting. This relates to a permanent condition of the 



