BOTANICAL TERMS. 



29 



POLLEX : the minute grains (alike in the same plant, but very 

 different in different plants) contained in the anther-cells, 

 commonly resembling a loose dust or powder (Fig. 140), 

 but sometimes cohering in sticky' masses (pollinia), as 

 in Orchis (Fig. 149). 



Pollen-grains are plant-cells having two coats, and 

 enclosing a thickish liquid. Fig. 150 shows a single 

 pollen-grain with its inner coat growing out in the form 

 of a tube. 



The pollen is the essential part of the stamen. The 

 pupil should examine with a good microscope various 

 kinds of pollen-grains, and make drawings of them. 



Number. 



If the stamens are not more than ten in number, the exact 

 number should be stated. If more than ten, they are 

 numerous or indefinite, and this is indicated by the sign 

 cc in the proper column of the descriptive table. 



Cohesion. 



If the stamens are entirely separate from each other, their 

 cohesion (or the absence of it) is described by prefixing 

 to the ending -androus the Greek prefix corresponding to 

 the number of stamens present, as follows : 



The cohesion is 



DiDYNAMOUS : if there are four stamens, two long and two 

 short (Fig. 151). 



Tetradynamous : if there are six stamens, four long and two 

 short (Fig. 152). 



MoNADELPHOUS : when all the filaments are grown together, 



leaving the anthers separate, as in Mallow (Fig. 153). 

 DiADEiiPHOUs : when the filaments are grown together in two 



sets, as in Pea (Fig. 154). 

 Triadelphous : when the filaments are grown together in 



three sets, as in St. John's Wort (Fig. 155). 

 Polyadelphous : when the filaments are grown together in 



more than three sets. 

 Syngenesious : when all the anthers are grown together, 



leaving the filaments separate, as in Dandelion (Fig. 155). 



Adliesion. 



Hypogynous : when inserted on the receptacle under the 

 ovary (Fig. 132, s). 



Perigynous : when inserted on the calyx (Fig. 133, s). 



Fig. 149. 



Fig 150. 



Fig. 151. 



Fig. 152. 



Fig. 153. 



Fig. 154. 



Fig. 155. 



Fig. 156. 



