FUBNS 



345 



The midrib of a compound frond is known as the rachis. In a 

 decompound frond, this main raohis is called the primary rachis. 

 Segments (not divided to the rachis) are seen at the tip, 

 and down to h on one side and to m on the other. 

 PinnsB are shown at i, k, I, o, n. The pinna o is entire; 

 l|n|f II is erenate- dentate ; i is sinnate or wavy, with an auricle 

 B.'w at the base; fc and I are compound. The pinna k has 

 twelve entire pinnules. (Is there ever an even number 

 of pinnules on any pinna ?) Pinna I has nine compound 

 pinnules, each bearing several entire ultimate pinnules. 

 Four pinnsB of the common wild 

 maidenhair fern are shown in Fig. 

 358; but is the maidenhair frond 

 pinnate ? 



427. We have now seen 

 that the spores, or "seeds," 



PiQ. 361. 



Scouring- 

 nish. 



Fig. 362. 



Ground-pine, a 

 club-moss. 



Fio. 363. 



A lycopodlum with 



sporangia in the axils of 



the foilage leaves. 



