344 



j:,:ESS02\rs wits plants 



frond between sheets of white paper. When the 

 frond is perfectly dry, the spores will be found 

 as a dnst-like covering upon the paper. 



426a. The primary complete divisions of a frond are called 

 pinnsB, no matter whether the frond is pinnate or not. In ferns 

 the word pinna is used in essentially the same way that leaflet is 



Fig. 359. 



Fronds of the sensitive 

 fern. 



Fig. 360. 



Diagram to explain the termi- 

 nology of the frond. 



in the onee-compound leaves of other plants. The secondary leaf- 

 lets are called pinnules, and in thrice, or more, compound fronds 

 the last complete parts or leaflets are ultimate pinnules. The dia- 

 gram (Fig. 360) will aid in making the subject clear. If the frond 

 were not divided to the midrib, it would be simple, but this dia- 

 gram represents a compound frond. The general outline of the frond, 

 :is bounded by the dotted line, is ovate. The stipe is very short. 



