332 GLOSSARY 



Indusium : in Ferns a flap-like membrane protecting a sorus. 143. 



Inflorescence : a flower-cluster. 230. 



Insertion : the point of origin of an organ. 224. 



Integument : in S[)ermatophytes a membrane investing the nucellus. 



178. 

 Involucre : a cycle or rosette of bracts beneath a flower-cluster, as in 



Umbellifers and Composites. 275. 

 IsocARPic : applied to a flower whose carpels equal in number the other 



floral organs. 268. 

 IsoGAMOUS : applied to plants whose pairing gametes are similar. 15. 



Leptosporangiate : applied to those Ferns whose sporangia develop 

 from a single epidermal cell. 157. 



Male cell: in Sperm atophytes the fertilizing cell conducted by the 



pollen-tube to the egg. 180. 

 Megasporangium : a sporangium which produces only megaspores. 152. 

 Megaspore : in heterosporous plants the large spore which produces a 



female gametophyte. 152. 

 Megasporophyll : a sporophyll which produces only megasporangia. 



152. 

 Mesophyll : the tissue of a leaf between the two epidermal layers which 



usually contains chloroplasts. 141. 

 MiCROSPORANGiUM : a sporangium which produces only microspores. 



152. 

 Microspore : in heterosporous plants the small spore which produces a 



male gametophyte. 152. 

 Microsporophyll : a sporophyll which produces only microsporangia- 



152. 

 Micropyle: the passageway to the nucellus left by the integument. 



178. 

 Moncecious : applied to plants in which the two sex organs are upon 



the same individual. 115. 

 Monopodial : applied to a style of branching in which the branches 



arise from the side of the axis. 35. 

 Mother cell : usually a cell which produces new cells by internal divi- 

 sion. 9. 

 Mycelium : the mat of filaments which composes the working body of 



a fungus. 49. 



Naked flower : one with no floral leaves. 222. 

 Nucellus : the main body of the ovule. 178. 



