5 OUR NATIVE FERNS AND THEIR ALLIES. 



CHAPTER II. 



THE ORGANS OF THE GROWING FERN. 



Pour bien savoir une chose, il faut en savoir les details. 



LA ROCHEFOUCAULD. 



20. EVERY one familiar with the forest and its products 

 must have seen the young ferns unrolling from the bud in spring 

 and early summer. It will be noticed that the fronds are coiled 

 from the apex to the base, and form crosiers, so called from their 

 resemblance to the head of a bishop's staff. This method of 

 vernation is called circinate, and is rarely found except among 

 ferns. In the grape-ferns and adder-tongues the vernation is 

 straight or merely inclined, thus approximating that of ordinary 

 flowering plants. 



21. Rootstock. Ferns usually spring from an under- 

 ground stem called the roof stock. This may be simple or 

 branched, smooth or scaly, horizontal, oblique, or even vertical. 

 In some ferns it is fine and hairlike, while in others it is very 

 large and stout. In some cases the rootstock creeps at the sur- 

 face of the ground and even rises above it, as in the variety of 

 Aspidium conterminum which grows in Florida. In the tree 

 ferns of warmer climates it often forms a trunk fifty feet high, 

 bearing the fronds at the summit, when it takes the name of 

 caudex. 



22. Frond. The aerial portion consists essentially of a 

 leaf-stalk and blade ; the former is technically called the stipe, 

 and the latter the frond. Though these are usually distinct 

 from each other in appearance, the stipe is sometimes wanting, 

 and in others no distinction can be made between them. Both 

 stipe and frond, or either one, may be glabrous (smooth), pubes- 

 cent (softly hairy), hairy, woolly, or scaly ; when the scales are 

 small and somewhat appressed, the surface is said to be squa- 

 mous. The careful discrimination of these hairy or scaly 

 appendages becomes a matter of importance in distinguishing 

 many of the species of Cheilanthes. In a few of our native ferns 



