224 Observation of flic Origin of Varieties. 



lariaccae,^ and of many other families, especially or- 

 chids.- The relation between this position and the reg- 

 ular form of the flower is still without a proper explana- 

 tion; and the question whether the anomaly is due to 

 high nutrition or to the absence of the factor which 

 determines the bilateral symmetry or both, still awaits a 

 definitive answer. Laterally situated peloric flowers are 

 very rare but sometimes occur as we have seen in Linaria 



Fig. 43. Antirrhinum ma jus. A, Peloric flower from the 

 middle of an otherwise normal raceme, August 1899. 

 Two slips of the corolla stand erect ; the other three are 

 bent downward. B, Normal flower of the same spike. 



vulgaris hernipeloria (Fig. 41, p. 207), and as is shown 

 by Antirrhimun ma jus (Fig. 43), etc. Of great impor- 

 tance, also, is the hitherto little noticed fact that in Digi- 

 talis and one or two other cases, the peloric terminal 

 flower opens first of all, whilst the order of opening of 

 all the other flowers on the stem is normal, i. e., acro- 

 petal. 



^EiCHLER, Bliithendiagramme, I, p. 208. 



''Pfitzer, in Engler and Prantl's Natilrl. PHanaen-Familicn: 

 Orchid., p. 61. For further information on pelorias of Orchids see 

 Penzig, Mem. Soc. naf. Sc. Cherbourg, Volj XXIX,, 1894, pp. 79-i04- 



