The Fekn I. over's Comfax 



23 



Veins 



The veins of a fern are free, when, branching from the 

 mid-vein, they do not connect with each otlier, and sim))le 

 when they do not fork. When the veins intersect they are 

 said to anastomose (Greek, an opening, or network), and 

 their meshes are called areola; or areoles (Latin, areola, a 

 little ojjen space). 



EXPLAXATIOX OF TeRMS 



A frond is said to he pinnate 

 (Latin, pinna, a feather), when its 

 primary divisions extend to the rachis, 

 as in tlie Christmas fern (Fig. 1). A 

 frond is hijjinnate (Latin, his, twice) 

 when the lobes of the pinna; extend to 

 the midvein as in the royal fern (Fig. 

 2). These divisions of the pinn;e are 

 called pinnules. When a frond is 

 tripinnate the last complete divisions 

 are called ultimate ])innules or seg- 

 ments. A frond is pinnatifid when its 

 lobes extend halfway or more to the 

 rachis or midvein as in the middle 

 lobes of the pinnatifid spleenwort 

 (Fig. .3). The pinnie of a frond are 

 often pinnatifid when the frond itself 



is pinnate; and a frond may be pinnate in its lower ])art 

 and become pinnatifid higher up as in the pinnatifid 

 spleenwort just mentioned (Fig. 'A). 



The divisions of a pinnatifid leaf are called segments; 

 of a bipinnatifid or tripinnatifid leaf, ultimate segments. 



