ii6 Our Native Ferns. 



Trichomes, (Gr. trlch 'ma, a growth of hair), hairs, variously modified as scales, in- 

 dnsia, sporangia, etc., produced from the epidermal cells, 42. 



Tripinnate, {tvis^ three, and pinna, a feather), three times pinnate. 



Tripinnatifid, {ti-is, three, pinna, a feather, and findere, to cleave), three times 

 pinnatihd. 



l^runcate, {truncare, to cut short), cut off abruptly. 



, Tufted, growing in clusters. 



U. 



Undulate, {undiUa, a little wave), wavy-margined. 



V. 



Variation among species, 18. 



Varieties, 47. 



Vascular, (vaseulum, diminutive of vas, a vessel), containing vessels as ducts, etc. 



Venation, (venOj a vein), the veining of the frond, 27. 



Vernation, (uer, spring), the arrangement of the leaves or fronds in the bud, 26, 43. 



Vittaria, (vitta, a fillet or bead-band), a genus of tropical ferns containing 13 spe- 

 cies; the type of Vittarieas, 73; also 21, 30, 61. 



Vittarieee, 61. 



w. 



Walking-leaf. Vide Camptosorus. 



Wood-fern. Vide Aspidium. 



Woodsia, (In honor of Joseph Woods, an English botanist), a genus of high tem- 

 perate or boreal ferns, containing 14 species, 95. 



Woodwardia, (In honor of Thomas J. Woodward, an English botanist), containing 

 6 species, mostly north temperate. 82 ; also 20, 27, 63. 



