XVI.] THE BEAN PLANT. 477 



luni) expanded at its free end and folded over 

 the rest. 



/?. On the sides, two oval pieces (ala\ each 

 attached by a distinct narrowed stalk (unguis). 



y. The inferior part of the corolla (carina), com- 

 posed of two oval pieces united along their 

 lower edge but readily tearing apart. 



4. The stamens. 



a. Ten in number, each consisting of a stalk-like 

 part, the filament, terminated by a small knob, 

 the anther. 



b. The union of nine of the filaments for three-fourths 

 of their length to form the staminal-tube, the tenth 

 being free : the sharp bend of the filaments to- 

 wards the upper side at the point where they sepa- 

 rate from one another. 



c. Tease out an anther in water and examine with 

 \ obj. : there will be found numerous 



a. Pollen-grains : small oval cells, with projections 

 on the cell-wall in the equatorial region. 



d. The anther of a bean is so small that sections 

 cannot be made of it without considerable skill: 

 the structure of an anther can however be easily 

 made out by imbedding one from a tiger-lily in 

 paraffin or holding it between two bits of elder- 

 pith, cutting transverse sections, mounting in water 

 and examining with i inch. obj. 



a. It contains four chambers, tJie pollen-sacs, two 

 on each side of the continuation of the fila- 

 ment, and in each chamber lie numerous pollen- 

 grains. 



