The Determinative Action of Environic Factors Upon Neobeckia acquatica Greene. 271 
being irregularly bi-pinnate with ultimate segments more than 1 mm 
wide. About the end of December grubs attacked two of the plants 
and they lost all of tlieir foliage. The roots were saved and a new 
crop of leaves soon appeared which were very finely dissected with 
segments less than 1 mm wide. Within a month after the appearance 
of the fine leaves on these plants the same sort of leaves were appearing 
on the plants which were not attacked. The average length of the 
leaves was 6 to 7 cm. From February until May the plants did well 
but underwent no further changes of leaf form.“ 
Still another series of cultures in the soil were carried out in the 
glass house attached to the Desert Laboratory at Tucson, Arizona. Three 
introductions have been made, and material has been drawn from them 
to various other places. Some individuals brought to Tucson in 1908 
are still alive despite the extreme summer temperatures to which they 
are exposed (100° F to 120° F). Establishment in the soil at this place 
was invariably followed by the appearance of nepionic leaves merging 
gradually into aerial dissected forms. It was notable also that very 
slight disturbances would cause rejuvenescence and a return to the 
broadly laminar leaves, and tliose which were formed in the period 
immediately following the cooler weather of January and February were 
characterized by a spread and area of surface far surpassing anything 
seen in the natural habitat of the plant, and also all other experimental 
condition s. 
A final introduction in September 1912 consisted of a number 
of stems of aquatics which had been packed in wet moss and shipped 
from the New York Botanical Garden by Dr. E. M. Kupfer. Those 
placed in small aquaria containing spring or well water showed a 
development of finely divided leaves from the terminal buds, while 
awakening lateral buds unfolded the usual series beginning with broadly 
laminar nepionic leaves. Other plants set in the soil formed nepionic 
leaves while plants already in position coincidently formed similar Organs, 
which might be attributed to the falling temperatures of the autumnal 
season. It was notable that terrestrials at this place were extremely 
sensitive to any disturbance. Stirring the soil around the thickened 
roots would cause the crown buds to unfold nepionic leaves. These 
plants remained in the rosette stage and the apex of the stem did not 
rise above the level of the ground at Tucson. 
About the l st of December 1912 it was noted that the divisions 
of the leaves on terrestrials and aquatics were very similar both in pattern 
and in the fact that the ultimate divisions were flattened and strap-shaped. 
18 * 
