232 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



In the single instance in which the endosperm is carried aloft, as 

 illustrated in Ria'niis, the amount of growth seems to be regulated 

 directly by the amount of food present, which is nearly all available 

 for the use of the developing plantlet. It is noticeable that this plant 

 affords not only an exaggerated growth in length of the hypocotyl, 

 but also allows the first internode of the plumule to reach a limited 

 development. The stems of Coix, Zea and Cocos are slightly 

 elongated in etiolated plants, while in Arisaema the stem takes the 

 form of an underground tuber, the aerial portion consisting of the 

 petiolated leaves, the tuber or corm being slightly attenuated as a 

 result of the etiolation. In all of the above instances the excessive 

 elongation consists chiefly in the increased length of a fairly normal 

 number of internodes, although Cocos developed one more than the 

 control specimens of the same age. 



A second group of seedlings consisted of species of dicotyledonous 

 woody plants with the reserve material present in large amount and 

 contained in cotyledons which remained buried in the soil, including 

 AEsciiIus, Castanca, Ilicoria and ^cercus. AEscuhis usually de- 

 velops one internode only during the first season of its growth, 

 but the etiolated plants extended nine, the basal one of which was 

 slightly longer than the normal. The various species of Hicoria 

 and ^lercus examined agreed in that the number of internodes was 

 never (Teater than in the normal, except in one unknown ^lerctis, 

 and in the case of J^. palusiris was actually less. In all instances 

 the etiolated stems were two or more times as long as the normal, the 

 most excessive increase in length being witnessed in the basal inter- 

 nodes. The food material stored in the nuts of the seeds is quite 

 perfectly protected from damage, and the greater part of it was avail- 

 able for the use of the plantlet. In consequence of this fact the 

 duration and actual period over which growth extended was very 

 long. In the case of a Ilicoria the seedling went into a resting 

 stage after a period of activity equal to a normal season and then 

 resumed growth, making several branches. This repeated growth 

 did not, however, entail the translocations and reconversions of 

 energy characteristic of the seedlings of Arisaema as described above. 

 The long-continued action of these woody seedlings implied some 

 radical departures from the usual method of morphogenic procedure, 

 which were most highly accentuated in the cortical tissues, and epi- 

 dermal elements. The species in question form a distinct bark on 



