EEVISION OF THE GENUS ISAJAS. 



387 



in Scandinavia. Najas graminea is an Old- World tropical species. N. Jlexilis is temperate 

 Nortli American and nortli-west European. N. microdon is its representative in the 

 ■warmer parts of America. The remaining species have all restricted areas and fall for 

 the most part into small geographical groups, namely an Asiatic, Australian, Mascarene, 

 African, and West Indian and tropical South American. The annexed table gives a 

 general view of the distribution : — 



Species. 



North Temp. 

 Europe. 1 Asia. 



Mediter- Tropical Aus- Mas- 

 ranean. | Asia. traha. carene. 



1 



Tropical „ . - . 

 Africa. S. Africa. 



N. Ame- 

 rica. 



W. Indies, 



Central 



&s. 



America. 



Pacific 

 Islands. 



1. Najas marina 



1 

 1 



1 



'l 



1 

 . . 



1 

 1 



1 



I'll 



1 1 



'.'. 1 



t 



1 

 1 

 1 



1 



1 



1 '.! 



1 

 1 





1 



1 

 1 



] 



1 



2. N. indica 





1 1 



3. JSI. Schweinfurthii .. 



4. N. Welwitschii .... 



5. N. madagascariensis. . 



6. N. aucistrocarpa .... 



7. N. ticxilis 



'] 



] 



l' 



* 

 • 



L* 





1 



8. N. podostemon .... 



9. N. microdon 









• 



10, N. punctata. . . 





11. N. microcarpa. 



12. N. Wrightiana 



13. N. conferta . . . 











14. N. arguta . . . 





16. N. minor 





1 



1 



1 



1 ; 



1 

 1 

 1 



1 

 1 

 1 



1 



1 



16. N. Kurziana . 



17. N. tenuissima . 



18. N. gracillima . 



19. N. Kingii . . . 



20. N. lacerata . . . 









21. N. foveolata . 



22. N. falciculata . 



23. '^. brcvistyla . 



24. §■. tenuifolia . 



25. N. Browniana . 

 2Q. N. Leichhardtii 



27. N. australis . 



28. ^. setacea . . . 









1 : 



1 



29. N. horrida . . . 





30. N. interrupta . 



31. N- graminea . 







4 1 4 



1 



3 



10 



5 4 



5 



1 



4 



8 



1 



I have no doubt that there are many species still to be found, and that exploration of 

 fresh or brackish waters, especially in tropical Africa, Malaya, and South America, will 

 yield interesting novelties and elucidate species which are at present insufficiently known. 



The hope of inducing botanists and collectors in various parts of the world to look out 

 for this interesting little genus must be my apology for publishing what I am convinced 

 is but a very incomplete monograph. Hitherto I have profited not only by the 

 collections at the British Museum and Kew, but also by those at the Calcutta Herbarium 

 kindly lent by Dr. Prain, and at Berlin, including Alexander Braun's types, for facilities 

 in the study of which I have to thank Prof. Engler. Mr. Charles Bailey, Prof. W. 

 il. Dudley of California, Dr. P. Zalewskiof Warsaw, and others have also courteously sent 

 me specimens. 



SECOND SEEIES. — BOTANY, VOL. V. 3 



