GLOSSARY. 273 



UNDULATE. Wavy-margined. 



VALLECULA (PL. VALLECUL^E). A hollow; especially the grooves 



in the stem of Equisetum. 

 VALLECULAR. --Pertaining to the valleculas. 



VASCULAR. Containing vessels, ducts, etc., as the stems of ferns. 

 VEIN. One of the small branches in the framework of a leaf. 

 VELUM. The indusium in Isoetes. 

 VENATION. The manner in which the veins are arranged in the 



leaf. 



VERNATION. The arrangement of leaves in the bud. 

 VIVIPAROUS. Producing young upon various parts of the plant. 

 WHORL. A circle ; as of leaves on a stem. 

 WINGED. Bordered with tissue, as the rachis of some ferns. 



