438 



TRANS. OF THE ACAD. OP SCIENCE. 



Greenii, and, very locally, J. Smithii ; north-westward, ex- 

 tending to the Rocky Mountains — J. alpinus and Vaseyi. 



6. Southward, mostly south-eastward and to the Gulf, 

 some of the species extending south-westwardly to Arkansas 

 and Texas — J. setaceus, dichotomies, repens, Elliottii, scirpoi- 

 des, caudatus, and asper, the latter only in the most north- 

 eastern limits of the region ; J. scirpoides as far north and 

 south-west as any of these species; south-westward, J. Buck- 

 ley i and a form of J", nodosus (the var. Texanus). 



7. On the Pacific slope, in the low country — J. compres- 

 stcs, Breioeri, patens, arcticus (var.), Bolanderi, and oxymeris. 

 The following extend from the coast to the mountains : J. 

 Mertensianus, xiphioides, and phctzocephalus, the two former 

 spreading eastward to and beyond the Rocky Mountains. 



8. Maritime species, north-east — J. Balticus, Gerardi, and 

 militarise the two former extending inland along the lakes, 

 the two latter also southward ; south-east — J. Bcemerianus; 

 Pacific coast — J. acutus, procerus, Balticus, sup-sp., and fal- 

 catus. 



9. Alpine and arctic species ; eastern — /. arcticus, trifidus, 

 and stygius; western — J. Drummondii, llallii, Parryi, tri- 

 glumis, castaneus, longistylis, chlorocephalus, saginoides; 

 the two last only on the Californian Alps. J. bighimis has 

 been found thus far soley in the highest arctic regions of our 

 continent. 



The following table exhibits at a glance the geographical 

 distribution of our species: 



Notes on the North American Species of Jdncus. 



1. J. acutus, Lin., has been found by Prof. Brewer near 

 San Luis Obispo, California, "where it is abundant in a 

 stream in the hills between the town and the landing of the 

 same name, a few miles from the sea, growing in dense tufts." 



