GAMETOPHYTE 431 
spores as in the Interrupted Fern (Osmunda Claytonia) (Fig. 382). 
In some like the Sensitive Fern (Onoclea 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. 883). 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 
Fic. 382. —A portion of a leaf of the Fic. 383. — The Sensitive 
Interrupted Fern (Osmunda Claytonia), Fern (Onoclea  sensibilis), 
showing a pair of vegetative leaflets above showing a vegetative frond 
and below and between them two pairs of at the left and a spore-bear- 
spore-bearing leaflets. 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 
