one variety required. This plan is good in theory, but it restricts the 

 distribution of sets; at present, however, no better way presents itself, 

 and the offer is still open. 



After a time, when a larger number of duplicates has been ob- 

 tained, the sets will be more widely scattered. Even now, four 

 numbers are exhausted and cannot be supplied to new applicants till 

 more be collected; these Numbers are 16, 22, 24 and 27. 



The species comprised in the Exsiccatae hitherto issued are : 



1. Nitclla tennis sima, Desv. , forma brevifolia. 



2. " intermedia, Nordst, nov. sp. 



3. " megacarpa, Allen, nov. sp. 



4. Chara intermedia, A. Br., forma tenuior, elongata. 



5. " intermedia, A. Br., var. Americana, A. Br. 



6. " contraria, A. Br., forma brachyphylla, humilior. 



7. " sejuncia, A. Br., forma elongata. 



8. " coronata, A. Br.,var. Schweinitzii, A. Br. 



9. " gymnopus, A. Br., var. Michauxii, A. Br. 



10. " hydropitys, A. Br. ,vir. Seplentrionalis, Nordst. in lit. 



11. " coronata, Ziz. Forma, microcarpa, microptila, verti- 



cillata (var. gracilis, Allen). 



12. " coronata, Ziz. Forma, meiocarpa, metioptila, partim 



unilateralia. 



13. " corona/a, Ziz. Forma, macrocarpa, meioptila, verti- 



cillata. 



14. " coronata, Ziz. Forma, macrocarpa macroptila, verti- 



cillata, zonulare incrustata. 



15. " excelsa, Allen. Bull. Torrey Bot. Club, 1882. 



1 6. " evoluta, Allen. Bull. Torrey Bot. Club, 1882. 



17. " fcetida, A. Br. , Forma, brachyphylla, clausa, elongata, 



macroteles. 



1 8. " fcetida, A. Br. Forma, incrustata, laxior. 



19. " conlraria, A. Br. 



20. " fragilis, Desv. Forma, tenuifolia, microptila, munda, 



humilior. 



21. " fragilis, Desv. Forma, microptila, incrustata, laxior. 



22. " delicatnla, Ag. non Desv. Ch. fragilis var. delicatula, A. Br. 



2 3- " gymnopus var. elegans, A. Br. 



24- " gymnopus var. Humboldtii, A. Br. Forma stolonifera. 



25. " sejuncia, A. Br. Forma, condensata, robustior. 



26. " aspera, (Dethard.) Willd. 



27. " aspera, (Dethard. ) Willd. Var. Macounii, Allen, in Bull. 



Torrey Bot. Club, 1882. 



28. Nitetta flexUis, Ag. 



