1913] YORK—DEN DROPHTHORA 205 
The inner ends of the cells are attached to a sort of membrane 
which is two or three cell layers in thickness. PrrRcE has described 
a similar structure, a “‘sclerotic membrane,” in Arceuthobium 
occidentale as being composed of three or four layers of tannin 
cells. Apparently there was no tannin in the cells of this body 
in Dendrophthora opuntioides. The viscin in Phoradendron flaves- 
cens presents essentially the same structure as that here just 
described, though this was not recognized by the author in his 
earlier studies on this plant. The layer of viscin surrounding the 
seed in Dendrophthora is much less in proportion to the size of the 
berry than in Phoradendron flavescens. In the latter the viscin 
evidently prevents extreme drying out and is useful in absorbing 
water before germination begins. It is not necessary for the ger- 
mination of the seeds, but if it is stripped from them they will dry 
up in a few weeks’ time when exposed to a dry atmosphere. Seeds 
from which the pulp has not been removed retain their vitality for 
an indefinite period of time. In January 1909, the author collected 
in Austin, Texas, berries of Phoradendron flavescens which were 
dried at room temperature. During June 1910, 12 of the dried 
berries were soaked in water for 24 hours, after which a part of the 
pulp was removed and the seeds were placed in a moist chamber. 
At the end of two weeks 4 of the seeds had begun to germinate. 
Owing to the warm moist environment of Dendrophthora opun- 
tioides, the pulp is probably not an important factor as a means 0 
protection and aid in germination of its seeds, since they germinate 
almost immediately after being deposited. 
The mature berries are bright red in color, oval in shape, 
7-9 mm. long, and 6-8 mm. in diameter. Owing to the peculiar 
order of origin of the flowers, various gradations in the develop- 
ment of fruits, from flowers to ripe berries, often occur in the same 
spike. The seed is enveloped by a thin layer of viscin, which is 
surrounded by a thick fleshly pericarp. The latter is covered by a 
heavily cutinized single-layered epidermis (figs. 22, 66). 
Embryo-formation in D. gracile 
The micropylar nuclei of the sac enlarge as much as they do 
in D. opuntioides. Meanwhile the two polar nuclei, which are 
