The Determinative Action of Environic Factors Upon Neobeckia acquatica Greene. 267 
Living plants of Neobeckia aquatica vvere obtained from the 
shores of South Bay of Lake Champlain in the autumn of 1902 and a 
few years later a socond supply was furnished by Prof. H. C. Co wies 
from pools in the vicinity of Chicago. Cultures from 1902 to 1906 
were made in the soil and in water in the New York Botanical Garden. 
Living plants were taken to the Desert Laboratory in 1906 and grown 
under glass as well at the Montane plantation at 8,000 feet as terres- 
trials. Some of the individuals grown here were taken to the Coastal 
Laboratory at Carmel, California near the shore of the Pacific in 1910. 
Flowers were formed but once in the ten years and all reproductions 
were from cuttings. 
Neobeckia is usually found rooted in the mud at the bottom of 
lakes and pools at a depth af 20 to 30 cm. Its most familiär aspect 
is that offered by the plant in bloom when an irregularly cylindrical 
stem extends above the surface of the water a few cm, the emersed 
part bearing a few oblong er oblong-ovate leaves or bracts subtending 
the terminal inflorescences. The submerged part of the stem bears 
finely dissected leaves and a dense cluster of these are usually found 
about the base of the stem. The plant is not found above the high 
water level. Almost any part of the shoot serves to propogate the 
plant and numerous individuals may be found upon the muddy Strand 
between high and low water levels. 
Nepionic leaves of seedlings have not coine under Observation 
during the course of this work. The emersion of aquatic individuals 
is usually followed by rejuvenescence consequent upon the changes in 
temperature, illumination, and moisture. The earlier leaves are entire 
or nearly so and successive Organs show an irregularly progressive 
dissection of the laminae beginning at the base, which results in pinna- 
tifid blades and finally carries the series on terrestrials into much 
divided Organs in which the ultimate parts are narrow and strap-shaped 
(Fig. 3). These aerial dissected leaves have not the spread and extension 
of the submerged dissected leaves, and wide differences exist between 
the structures presented by the two types. 
The senescent leaves of aquatics are formed on the terminal por- 
tions of stems above the surface of the water are in ordinary appearance 
quite like the senescent Organs of terrestrials. No wild terrestrial plants 
have been found in which stems were formed, but it seems very probable 
that they may have been developed by many plants in a state of nature. 
A number of cultures were made to ascertain the reaction of the 
plant under various environic conditions. Plants which had been grown 
