1915) Bergen,— Weed Growth and Unusual Rainfall 225 
Herbaceous vegetation in general has grown more vigorously than 
usual in consequence of the abundant water supply. A few examples 
from a grassy vacant lot in Cambridge, with very poor sandy soil, may 
suffice to illustrate this. Ambrosia artemisiifolia showed plenty of 
specimens growing to a height of 1.5 metres; Oenothera biennis reached 
a height of 1.72 metres; Erechtites hieracifolia (a moisture-loving plant 
which does not usually grow at all in this bit of ground) was 2.0 metres 
high Helianthus grosseserratus, growing in tough sod near by, 
reached a height of 3.3 metres. The annual weeds of the field and 
garden are perhaps rather more sensitive in their responses to varia- 
tions in their environment than most seed plants. Competition is 
especially sharp among these species and they have no such monopoly 
of their seed beds as do many plants which grow in uncultivated soil. 
Mos: of the species which the agriculturist reckons as weeds are meso- 
phytes, but the range in water requirement between such a plant as 
the ox eye daisy, Chrysanthemum Leucanthemum, var. pinnatifidum 
and such a one as the great ragweed, Ambrosia trifida, is rather wide. 
For convenience some of the common weeds of New England in 
regard to which the writer has been able to obtain notes this summer 
may be arranged in three groups: 
1. Those which are decidedly more vigorous than usual. 
2. Those which show little difference in growth from that of ordi- 
nary seasons. 
3. 'Those which are relatively less important than in ordinary 
seascns. 
Prominent among the first group are the coarse annual grasses, 
finger grass, Digitaria humifusa, crab grass, Digitaria sanguinalis, 
barn yard grass, Echinochloa crusgalli, and old witch grass, Panicum 
capillare. These are all shallow-rooted species, with large and proba- 
bly actively transpiring leaf surfaces. The only common representa- 
tive of Cyperaceae is the rather abundant, very variable, tuber-bearing 
Cyperus strigosus. Other weeds much in evidence this season are 
lady's thumb, Polygonum Persicaria, horseweed, Erigeron canadensis, 
ragweed, Ambrosia artemisiifolia, and beggar ticks, Bidens frondosa. 
All these weeds, though they are troublesome in ordinary soils and 
every year, flourish best when they can get an abundant supply of 
mois-ure. 
The weeds which the writer has found to be not much more conspicu- 
ous and annoying this year than usual are many of them among the 
