136 



PRINCIPLES OF PLANT-TERATOLOGY. 



that half of each lateral sepal nearest the labellum was 

 labelliform. This phenomenon was also observed in 

 Gattleya labial a. 



Forms of the snowdrop (Galanthus nivalis) have 

 been seen in which all six perianth-leaves had the form 

 and coloration of the petals, due to petaloid trans- 

 formation of the usually white and larger sepals. The 

 Sachsian explanation of these cases of the orchids 

 and snowdrop, adopted by Goebel and others, is surely 

 no explanation at all; the same material which normally 

 goes to the building of a petal only has in these cases 

 also been employed for that of a sepal, hence the 

 petaloid appearance of members of the outer whorl; but 

 this proposition merely suggests the further question : 

 what has directed this inflow of petaloid material into 

 the outer whorl? and we are just where we were before ! 



Petalocly of the calyx seems to indicate community 

 of origin of calyx and corolla, viz., from the andrcecium; 

 that petal and sepal are one and the same organ ; and 

 in this sense the phenomenon may be regarded as a 

 reversion from the more recent differentiated condition. 



Staminody. — This is much rarer. Gris records an 

 instance of a flower of the mock-orange (Philadelphns 

 speciosus) in which one of the divisions of the calyx 

 bore an anther-loculns. A flower of the Dutch clover 

 (Trifolium repens) was seen in which one or two of the 

 semi-petaloid sepals bore anthers ; also tulips in which 

 most of the sepals had lateral lobes (of which more 

 hereafter) and one of them bore a fertile anther ; 

 similarly-lobed sepals were seen in Crocus zonatus. For 

 reasons which will appear later these lobed perianth- 

 leaves of the tulip and crocus are here regarded as 

 partial, imperfect reversions to the stamens from which 

 they originally sprang. 



Magnus observed fusion of the odd sepal with the 

 " column " in the orchids Gattleya labiata and Tricho- 

 pilia tortilis; he attributes this to the pressure caused 

 by the fused perianth- bases in the bud; but this would 

 hardly occur unless there was an innate tendency, due 



