GAMETOPHYTE 



431 



spores as in the Interrupted Fern (Osmunda Claytonia) (Fig. 382). 

 In some like the Sensitive Fern (Onodea sensibilis), common along 

 roadsides and in wet meadows, there are two distinctly different 

 kinds of fronds, one of which is entirely devoted to bearing spores 

 and the other entirely to vegetative 

 work (Fig. 383). This separation of 

 spore-bearing and vegetative tissues 

 is adhered to more closely in some 

 other Pteridophytes than in the 

 True Ferns, and it is a feature 



FIG. 382. A portion of a leaf of the 

 Interrupted Fern (Osmunda Claytonia), 

 showing a pair of vegetative leaflets above 

 and below and between them two pairs of 

 spore-bearing leaflets. 



FIG. 383. The Sensitive 

 Fern (Onodea sensibilis), 

 showing a vegetative frond 

 at the left and a spore-bear- 

 ing frond at the right. 



of considerable significance because it is characteristic of Seed 

 Plants. 



Gametophyte. When the spores are shed and fall in moist 

 places, the protoplasm breaks the spore wall and begins the de- 

 velopment which results in the production of a gametophyte. 

 In True Ferns a short tube with one or more rhizoids at the spore 



