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 Stipa comata Trin. & Rupr., known in the west as 
porcupine or blow-out grass. Its natural range is from lowa to 
Texas, California and Yukon. It is an interesting addition to the 
already long list of western plants which have become established 
in 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 
western 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 I9I10 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. 
Gaura coccinea Pursh 
Gymnolomia multiflora 
Benth. & Hook. 
Helianthus petiolaris Nutt. 
Lappula echinata Gilibert 
Lygodesmia exigua A. Gray 
Artemisia carruthi Wood 
s biennis Willd. 
a dracunculoides Pursh 
s frigida Willd. 
glauca Pall. 
4 trifida Nutt. 
(Nutt.) 
Anogra albicaulis (Pursh) Britton 
Allionia hirsuta Pursh 
Aster multifolius Ait. 
Chaenactis stevioides Hook. & Arn. 
Bidens tenuisecta A. Gray 
Chrysothamnus pinifolius Greene 
Boebera papposa (Vent.) Rydb. 
(Drysodia papposa (Vent.) Hitchc.) 
Grindelia squarrosa (Pursh) Dunal 
is squarrosa nuda A. Gray 
Machaeranthera pulverulenta (Nutt.) 
Greene 
i tanacetifolia (H. B. 
K.) Nees 
Monolepis nuttalliana (R. & S.) 
Greene 
Salsola pestifer A. Nelson 
Sideranthus gracilis (Nutt.) Rydb. 
Verbena bracteosa Miche. 
Stipa comata Trin. & Rupr. 
