'899* J Johnson. — The Irish Chamceas. 149 



B. Crown or corona of i-celled filaments, i.e., crown is 5-celled. 



II. Chares. 

 a- Without whorl of stipuJes. 3. Tolypelbpsis. 



b. With whorl of stipules. 

 aa. Oogonia standing below the antheridia; 



uncortexed ; monoecious. 4. Lamprothamnuu 



bb. Oogonia mixed with the antheridia ; 



incompletely cortexed or uncortexed ; monoecious. 



5. Lycnothamnus*, 

 ce. Dioecious or monoecious ; in latter case oogonia above antheri- 

 dium ; cortexed or uncortexed. 6. Ckara. 



REVIEW OF SPECIES OF NITELLA, Agardh. 

 I. Leaves only once divided, end segments i-celled, Corona deci- 

 duous : JMonarthrodactyke (Flexiles). 

 f [A. Sexual organs with gelatinous envelope : Glccocarpa. 



a. Female leaves unforked, oospore or nucule smooth. 



1. N. syticarpa. 



b. Female leaves forked, oospore or nucule with bands. 



2. N. capitata.] 

 B. Sexual organs without gelatinous envelope : 



Gymnocarpa. 



a. dioecious. 3. N. opaca. 



b. monoecious. 4- Af. flcxilis. 



II. Leaves repeatedly divided, end-segments 2 or 3-celled, Corona 

 persistent : Diarthrodaclyla. 



A. Whorls without or, only occasionally with, accessory leaves : 



Honiixophylhe, 

 a, Sexual organs without gelatinous envelope : 



Gymnocarpa. 

 a. End segments short, with the lateral leaflets also short, 

 producing an insignificant corona : Coronate. 



Fertile leaves crowded together into very small masses, 

 end segments of leaves scarcely recognisable with the 

 naked eye. 5- Af. trans! nans. 



i3. End segments longer, forking of the leaves distinct, 

 the last cells of the end segments attached as a short 

 corona to the preceding cells, which are several times 

 longer. Mticronata, 



1 . Sexual organs at several rays. 



* Oospore or nucule with sharp bands. 



[7. N. mitcrcuafa.2 



* Oospore or nucule with slight bands. 



* Not British. 



■f [ ] = not Irish but step inserted as a guide for comparison. 



