THE DEHISCENCE OF ANTHERS BY APICAL PORES. 213 



which open at least at first by terminal pores. Since the 

 floral habit of this family conforms to that of our Dillenia- 

 ceous and Solanum-Cassia types, the only opportunity for 

 comparisons is between the genera which may be assigned 

 to these two types and certain aberrant forms to be men- 

 tioned below. We may postulate that the Solanum-Cassia 

 type has in some cases been derived from the Dillenia- 

 ceous type by a numerical reduction of the androecium ac- 

 companied in most instances by a shortening of the fila- 

 ments. On the whole, dehiscence by pores seems to be 

 more perfected in the Solanum-Cassia type. A family con- 

 taining representatives of both types should furnish data 

 of value for a study of this question but, as pointed out 

 above, the evidence available in the present case is too 

 meager. A strong reduction in the androecium has clearly 

 taken place so that the family is broken up into more than 

 one floral type, but whether this reduction occurred entirely 

 subsequent to the development of the apically dehiscent 

 habit or whether it largely preceded it is a question which 

 cannot be easily decided. The anthers of some species of 

 this family which have been assigned to the Solanum-Cassia 

 type show no more specialized apical dehiscence than some 

 which have been assigned to the Dilleniaceous type. On 

 the other hand it is to be noticed that certain genera are 

 very suggestive of the Melastomataceous type — a group of 

 forms the evolution of which has apparently progressed 

 along a very different line from that of the Solanum-Cassia 



type 



and this may explain the equal perfection of apical 



dehiscence in forms with numerous stamens with long fila- 

 ments and in those with few stamens with short filamenta. 

 In certain anomalous genera the staminodia are so modi- 

 fied as to form a more or less perfected tubular or urceolate 

 corona. In these genera, the anthers open by longitudinal 

 slits and since the same condition prevails in other genera 

 with an urceolate perianth in families in which the perianth 

 is usually patent and the dehiscence apical, it seems legiti- 



