852 THE JornxAL of botany 



reversionary, the re-a])pearance of the posterior sepal and of the two 

 posterior petals being instances of pure reversion, and tlie occurrence 

 of petaloid staminodes a case of modified reversion. In 7 ilowers the 

 corolla was 8-lobed, owing to the suppression of the anterior petal. 

 On the same hypothesis this may be regarded as a progressive abnor- 

 mality. Hence at least 73 out of 78 abnormalties — that is, nearl}^ 

 94) per cent. — seem to possess evolutionary significance. As will be 

 seen later, the ratio between the reversionary and the progressive 

 variations depends largely on edaphic conditions. The remaining -5 

 abnormalities we-re as follows : — anterior sepals foliaceous in two 

 Ilowers; right-hand anterior sepal bilobed ; anterior and right-hand 

 lateral petals connate ; right-hand posterior stamen represented by a 

 petaloid staminode. The last three abnormalities occurred only once. 



The five double abnormalities were as follows : — posterior sepal 

 associated with two posterior petals in two cases ; two posterior ]:>etals 

 associated with one anterior staminode ; two posterior petals with a 

 right-hand posterior staminode ; and a bilobed posterior corolla-lobe 

 with one anterior staminode. 



As it seemed desirable to study further material, 220 flowers with 

 abnormal corolla or androt^cium were examined. Thirty-seven flowers 

 exhibited two abnoimalities each and one had three, the total 

 number of abnormalities being 259. 



A bilobed posterior corolla-lobe occurred in 46 flowers, and two 

 posterior lobes were present in 41 flowers. A posterior sepal was 

 associated with a bilobed posterior corolla-lobe in 9 cases out of 4(3 

 (195 per cent.), and with two posterior lobes in 19 cases out of 41 

 (4G per cent.). This seems to indicate, as might be expected, that 

 the greater the amount of division of the posterior corolla-lobe, the 

 greater will be the probability of the occurrence of a posterior sepal. 

 One of the flowers in which a posterior sepal was associated with two 

 posterior corolla-lobes had also a sixth sepal between and distinctly 

 outside the posterior and right lateral sepals. This may be regarded 

 as an inconsequent abnormality. 



An anterior petaloid staminode occurred in 22 flowers, and Avas 

 associated in four cases with the presence of a iDOsterior sepal and in 

 two cases with a bilobed posterior corolla-lobe. 



A trimerous corolla occurred in 105 flowers, the anterior petal 

 being suppressed in 101 cases, the right lateral in two cases, and the 

 left lateral in, one. In the remaining case the ti'imerous condition 

 was due to the fusion of the anterior and right lateral petals ; the 

 right anterior sepal was almost in the antero-posterior plane, and the 

 left anterior sepal was displaced backwards and connate nearly to the 

 ap ^x with the left posterior sepal. Thus trimery of the corolla was 

 attuned in three Avays : by suppression of the anterior petal (101 

 cases), by suppression of a lateral petal (3 cases), and by fusion of 

 the anterior petal with a lateral one (1 case). One of the flowers 

 which had a trimerous corolla by suppression of the anterior petal had 

 only three sepals, each 3-nerved, the anterior being slightly larger 

 than the other two, but showing no sign of a double nature. Another 

 flower in which the anterior petal was suppressed had the two anterior 

 sepals connate. In the remaining 99 cases the calyx was normal. 



