270 GLOSSARY. 



Hirsute. — Having coarse stiff hairs. 



Imbricated. — Overlapping or breaking joints, lil^e shingles on a roof. 



Incised. — Cut into deep, sharp teeth. 



INDUSIUM (Pl. Indusia). — The thin, scaie-lilie covering of immature 



sori. 

 Internode. — The spaces between the nodes of the stem, especially 



in Eqitisetum. 

 Involucre. — The cup-shaped process surrounding the sporangia 



in the filmy ferns ; an indusium. 

 ISOSPOROUS. — Producing spores of one kind. 

 Laciniate. — Cut into deep, narrow, irregular lobes ; slashed. 

 Lanceolate. — Rather narrow and tapering to the apex ; occasion- 

 ally tapering at base also. 

 Lamina. — A blade ; the leafy portion of a frond. 

 Leptosporangiate. — Producing sporangia from the superficial 



tissues of the frond. 

 Ligule. — A small triangular tongue-like organ on the leaves of 



Isoetes. 

 Linear. — Long and narrow. 

 Lobe, — One of the small divisions of a frond. 

 Lunate. — Shaped like a half-moon. 

 MacrospORE. — A megaspore. 

 Marginal. — Situated on, or close to, the margin. 

 Megaspore. — The larger spore in those species having two sizes of 



spores, especially in Isoetes. 

 Membranaceous. — Like a membrane ; very thin and flexible. 

 Microspore. — The smaller spore in those species with spores of two 



sizes, especially in Isoetes. 

 Midrib. — The prolongation of the stipe through an undivided frond 



or pinna. 

 MiDVElN. — The principal vein in a pinnule or segment. 

 MUCRONATE. — Having the midvein prolonged beyond the pinnule, 



forming a point. 

 Node, — The swollen regions of a stem from which the leaves grow, 



especially in Equisctuin. 

 Oblanceolate.— The reverse of lanceolate ; broadest near the 



apex. 

 Oblong. — Two or three times longer than broad. 



