“1904] BRIEFER ARTICLES 215 
or so high, I take off the paper and plaster, cut off the cotyledons, and thus 
force the peas to draw all their water and mineral salts from the bean plants. 
This they do successfully. 
By such a simple method as this I compel peas to live on bean-plants 
in essentially the same degree of parasitic dependence as that of Viscum 
or Phoradendron upon oaks. What are the results? These will be shown 
by extracts from my laboratory notes. 
January 27; 1902. Peas set November 12 on beans and in dirt in same 
boxes began to bloom; one flower on a bean-pea, several on soil-peas. 
Great difference in size of plants, number and area of leaves, size of flower 
and of parts of flower, between bean-peas and soil-peas. Weather since 
November 12 dry and cold for the most part. 
These plants were grown out of doors in a cold frame on the southwest 
side of the laboratory building. The frame was usually open from nine 
or ten o’clock until four or five daily, the hours of opening and closing 
depending mainly upon the temperature. The boxes used were shallow 
and the soil poor. The soil-peas were about half the size which the plants 
of the same variety would attain later in the season in rich soil of proper 
depth. The bean-pea plants were about one quarter to one half the size 
of the soil-pea plants growing in the same boxes, but were well proportioned 
and stocky. 
From these plants I harvested a crop of ten good seeds from the bean- 
peas and ninety-three from the soil-peas. On the bean-peas there were 
only two or three peas in-a pod, and the pods were small and rather thin, 
splitting normally when dry. 
These pea-seeds I subsequently measured by vernier caliper. The 
“dry, ripe seeds were not uniform in shape, and rather than take the 
largest diameter in each case I decided to measure through the same points, 
as nearly as possible, in each seed, viz., on a line bisecting the hilum at a 
right angle, holding the hilum toward my lefth and, the caliper being in 
my Tight. Of the bean-peas three were decidedly smaller than the rest. 
air. 
Thickness of smallest beali-pea seed. sae eke eee 5.25mm 
Thickness of largest Deah-pea seed... 60.20. ca ce es 6.95 
Average thickness of 10 beka-pes Seedai ie 6.31 
Average thickness of 7 larger bean-pea seeds............. 6.66 
Average thickness of 3 smaller bean-pea seeds..........-. 5.48 
a oo similarly the 93 seeds, ripe and air-dry, which I had gathered 
t © Pea-plants grown in the soil. Three of these peas were more 
me — in thickness, one was 5.12™m_ This last was smaller than 
Y Dean-pea. There were also fifteen among these soil-peas which were 
