250 



PRINCIPLES OF PLANT-TERATOLOGY. 



inflorescence ; it consisted solely of a single notched 

 sepal formed by fusion of the two lateral ones ; its 

 dorsal side was directed towards the axis. In the 

 early purple orchis (0. mascula) he saw a similar case. 



Gramosepaly is, of course, a normal feature in the 

 GamopetalaB. 



We may next consider instances of suppression. In 

 Gucurbita in a 6-merous flower two sepals were seen 

 fused together and one was vestigial, leaving four. 



In Gypripedium insigne a 2-merous flower showed 

 the complete absence of the " posterior " sepal owing 

 to the abnormal presence in that position of a labellum. 

 The flowers above-mentioned of Epidendrum and 

 Trichopilia involved in their structure suppression of 

 sepals. 



In Dendrobium Wordianum the same phenomenon 

 occurred ; the two lateral petals had become united 

 and occupied the position of the " posterior " sepal. 

 All the flowers of the plant were affected in the same 

 way (PI. LTII). 



The small secondary flowers, axillary to the sepals 

 of the primary flower, in a cyclamen, had the calyx 

 composed of two sepals only, and these were much 

 reduced. 



2. Petals. — One of the best-known and most 

 remarkable instances of sympetaly occurs in a variety 

 of the Oriental poppy (Papaver orientale) in which 

 the corolla forms a large cup, due to union of the four 

 petals ; there is a slight tendency towards fusion of 

 the petals in the normal flower (PI. LI, fig 10). 



In the large group Gamopetalge the phenomenon 

 is, of course, the normal feature. 



The gamophyllous condition of the perianth is of 

 progressive nature. The Gamopetala3 represent the 

 most advanced in evolution of all plant-groups. 



Those phenomena are next to be mentioned in which 

 some, but not all, of the petals become coherent. 



The case of Dendrobium Wardianum has been cited 

 above in which the two lateral petals became united 



