136 



ELEMENTARY STUDIES IN BOTANY 



rangia come together (Fig. 104), but sometimes there is 

 formed an opening (pore) at the top, which may even be 

 extended into a tube (Fig. 107). 



The stamens, like the petals and sepals, are not always 

 free from one another, for sometimes the filaments appear 

 as if they had been united. In some plants, for example, 



FIG. 107. Anthers opening by terminal pores: A, potato or tomato; B, arbutus; 

 C, cranberry or huckleberry. A and B after ENGLER and PRANTL, C after KEENER. 



the stamens appear united in this way in two or more sets, 

 and sometimes they. form a single set, all of the filaments 

 together forming a tube (Fig. 108). In sympetalous corol- 

 las it is usual for the stamens to appear as if arising from the 

 tube of the corolla (Fig. 102, ). This means that the petal 

 set and stamen set have developed together, so that they are 

 not distinct from one another at base. 



While the two kinds of sporophylls (stamens and carpels) 

 are usually associated in the same flower, there are many 



