THE DEHISCENCE OF ANTHERS BY APICAL PORES. 197 



longitudinal slits. Solarium furnishes one of the classic 

 illustrations of the apically dehiscent anther, and the large 

 number of species in which the pores are continued down 

 the sides in longitudinal slits stands as a justification for • 

 including in the apically dehiscent category several genera 

 in which the pores are later supplemented by lateral slits. 

 Between the two forms of dehiscence, no sharp line exists 

 although in the individual cases it is usually not difficult 

 to decide very satisfactorily to which category a form 

 should be referred. 



In Cypliomandra (about 35 tropical American species, 

 especially numerous in Brazil, and 2 extratropical South 

 American species), the species of which were formerly 

 treated under Solarium , the structure of the anther differs 

 somewhat from that of Solatium. In some of the species 

 at least, the walls are very thin and elastic, so that the 

 pollen is puffed out by a bellows-like action. This genus 

 is, in my present judgment, to be regarded as a specialized 

 representative of the Solanum-Cassia type. 



In the Solanaceae the gamopetalous corolla is tubular, 

 infundibuliform, hypocrateriform, campanulate or rotate. 

 I shall not give here a detailed discussion of the structure 

 or distribution of the genera or species which approach 

 Solatium in floral habit, but from quite careful comparison 

 I may state with some confidence that Solanum represents 

 the form in which the anthers have attained the greatest 

 length and the filaments are the most reduced. 



Rubiaceae. 



Argostemma (30 



1 in 



West Africa) 



some species of which belong clearly to this type. Only 



30-40 



me 



these species are. 



Neurocalyx (about 6 species especially in Ceylon, but 



