272 
Mac Doiigal, 
The growth of the species as a terrestrial entailed among other 
departures from the experience of the plant the endurance of a great 
ränge of temperature during the year and also daily. It was notable 
that full maturity of the plant was not reached under such circum- 
stances until conditions were provided in which this feature was of a 
character approximating that of the habitat of the plant. Individuals 
grown as terrestrials in the glass house of the Desert Laboratory were 
taken to the Coastal laboratory in October 1910. The climate was oceanic, 
the temperature falling below the freezing point but a few hours in 
each year, and the total exposure above 70° F is comparatively small. 
Under such conditions elongated aerial stems with narrow senescent 
leaves were formed in 1911 and in 1912, while in 1913 one plant 
proceeded to the development of full inflorescence. 
Fig. 10. Cross section througk a ter¬ 
restrial leaf segment of Neobeckia. 
Fig. 11. Cross section through a part 
of a leaf from the terminal part of a 
stem of Neobeckia. 
A comparison of the structures of aquatic and terrestrial plants 
was made from material grown in the New York Botanical Garden. 
The first lot of cuttings were placed in the soil in pots in 1902. These 
soon underwent rejuvenescence, sending out roots and beginning with 
the formation of the oblong-ovate nepionic leaves which were followed 
by the usual series of aerial dissected forms. The epidermal elements 
of such leaves were flattened but the parenchymatous elements were 
arranged with their greatest diameters perpendicular to the surface, 
and ample intercellular spaces communicated with the external air through 
the Stomata (Fig. 10). The Stomata were much more abundant per 
unit area on these organs than on the leaves or bracts near the in- 
