58 



b Corticated. 



X Cortex of the stem consists of a series of homogeneous cells, 

 equal in number to the leaves, but in disunited series. 

 Leaves also singly corticated in disjoined series. 

 Dioecious. 23. imperfecta A. Br. 

 Monoecious. 24. inconnexa Allen. 

 X X Stem perfectly corticated by cells of different sorts. 



HAPLOSTICHJE. Series of cortex cells equal in number to 



the leaves. 

 -|- True haplostichae. 



Q Dioecious. 25. crinita Wallr. 

 QQ Monoecious. 

 -| |- Falsely haplostichous (a secondary series of cells more 



or less intermixed). 



Q Dissolutac ; the secondary series of cortex cells dis- 

 tant or undeveloped ; leaves naked or corticated 

 like the stem. 



Nucleus 780 long. 26. dissoluta A. Br. 

 QQ Contiguae. 



1) Leaves singly corticated. 



a Nuclei smaller. 27. altaica A. Br. 



b Nuclei larger (subsp. ) 28. evoluta Allen 



2) Leaves naked (sub-species of contraria. ) 29. nudi- 



folia A. Br. 



DIPLOSTICH^E. 



* Primary cells of the cortex prominent ; Tylacanthae ; 



see p. 21. 

 X Dioecious. 



Q Large, stem with spines ; corticated segments of 

 the leaves commonly 3. 30. ceratophylla 

 Wallr. 



QQ Slender, stem with papillae, all segments of the 

 leaves naked or one corticated. 31. Kirghis- 

 orum, Lessing. 

 X X Monoecious. 



Q) Sporophydia smaller. 



Qj. Cells of the cortex few, spines few, often scarcely 



developed. 



a) Leaves doubly corticated. 

 Q Verticils not extremely short. 32. contraria 

 A. Br. 



