38 NEW YORK STATE MUSEUM 



WESTERN PLANTS INTRODUCED AT ROCHESTER 



BY HOMER D. HOUSE 



Among some specimens received for identification from Prof. 

 M. S. Baxter, of Rochester, was found a grass which was deter- 

 mined as S t i p a c o m a t a Trin. & Rupr., known in the west as 

 porcupine or blow-out grass. Its natural range is from Iowa to 

 Texas, California and Yukon. It is an interesting addition to the 

 already long list of western plants which have become established 

 iiL the vicinity of the Cobb's hill reservoir at Rochester and collected 

 there by Mr Baxter and by Miss Beckwith. 



With the cutting away of the forests of the east and the gradual 

 drying up of a large portion' of the soil, the tide of weed migration 

 from European countries has been met by a countermigration of 

 western species, which are largely adapted to dry situations, into 

 the fields and waste places of the eastern states. 



Following the construction of the Cobb's hill reservoir at Roch- 

 ester, a rather notable establishment of western species took place. 

 This may be partly explained by the use of western hay or grain 

 for the animals used in the work, if such was the case. In the ab- 

 sence of evidence regarding the means by which the seeds of these 

 w€istem species reached Cobb's hill, and the fact that few of them 

 have been reported from other eastern localities would seem to 

 indicate that the seeds reached there in either hay or grain. 



During the summers of 1910 to 1914, a large number of these 

 western emigrants were collected there by Prof. M. S. Baxter and 

 by Miss Florence Beckwith. The list of them which follows in- 

 cludes only those deposited in the State herbarium. 



Artemisia carruthi Wood Gaura coccinea Pursh 



" biennis Willd. Gymnolomia multiflora (Nutt.) 



" dracunculoides Pursh Benth. & Hook. 



" frigida Willd. Helianthus petiolaris Nutt. 



" glauca Pall. Lappula echinata Gilihert 



" trifida Nutt. Lygodesmia exigua A. Gray 



Anogra albicaulis {Pursh) Britton Machaeranthera pulverulenta (Nutt.) 



AUionia hirsuta Pursh Greene 



Aster multifolius Ait. " tanacetifolia (H. B. 



Chaenactis stevioides Hook. & Am. K.) Nees 



Bidens tenuisecta A. Gray Monolepis nuttalliana (R. & S.) 



Chrysothamnus pinifolius Greene Greene 



Boebera papposa {Vent.) Rydh. Salsola pestifer A. Nelson 



(Drysodia papposa {Vent.) Hitchc.) Sideranthus gracilis {Nutt.) Rydh. 



Grindelia squarrosa {Pursh) Dunal Verbena bracteosa Michx. 



" squarrosa nuda A. Gray Stipa comata Trin. & Rupr. 



