270 GLOSSARY. 



HIRSUTE. Having coarse stiff hairs. 



IMBRICATED. Overlapping or breaking joints, like shingles on a roof. 



INCISED. Cut into deep, sharp teeth. 



INDUSIUM (PL. INDUSIA). The thin, scale-like covering of immature 



sori. 

 INTERNODE. The spaces between the nodes of the stem, especially 



in Eqtdsetiiui. 

 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. 

 MACROSP.ORE. 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. 



MIDVEIN. The principal vein in a pinnule or segment. 

 MUCRONATE. Having the rnidvein prolonged beyond the pinnule, 



forming a point. 

 NODE. The swollen regions of a stem from which the leaves grow, 



especially in Equisctum. 

 OBLANCEOLATE. The reverse of lanceolate ; broadest near the 



apex. 

 OBLONG. Two or three times longer than broad. 



