824 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



BETULACE^. 



514. Betula occidentalism Hook. 



1874. August. Eocky Mountains. 



SALIOACE^. 



515. Balix lucida^ Muhl. 



1873. August. Mouse River. 



516. Salix rostrata, Eichardson. 



1873. July. Pembina, in fruit. 

 *517. Salix nigra, Marsh. 



*518. Populus halsamifera, L., var. candicans. 

 *519. Populus monilifera, Ait. 

 *520. Populus tremuloides, Mx. 



CONIFERS. 



*521. Pinus BanTcs'^ana, Lambert. 

 *522. Pinus contorta, Doug. 

 *523. Pinus resinosa, Ait. 

 524. Abies Bouglasii, Lindl. 



1874. Eocky Mountains. 

 *525. Abies alba, Mx. 



*526. Abies Engelmanni, Parry. 

 *o27. Abies nigra, Torr. 

 *528. Abies balsamea, Marshall. 

 *539. Larix Americana, Mx. 

 *530, Thuja occidentalis, L. 



531. Juniperus comonunis, L. 



1874. August. Eocky Mountains. 



532. Juniperus SaMna, L. 



1874. August. Base of Eocky Mountains. 

 *533. Juniperus Virginiana, L., var. procumbens. 



AEAOE^. 

 534. AriscBma triphyllum, Torr. 

 1873. July. Pembina. 

 *535. Galla palustris, L. 

 *536. Acorus Calamus, L. 



LEMNACE^. 

 537. Lemna trisulca, L. 



1873. Pembina, with Ranunculus cymbularia. 

 '^538. Lemna minor, L. 



TYPHAOEiE. 



*539. Typlia latifolia, L. 



540. Sparganium simplex, Huds. 

 1873. July. Pembina. 

 *541. Sparganium eurycarpum, Eng. 

 *542. Sparganium natans, L. 



