ie, 
ASCIDIA IN GASTERIA AND AGAVE. 127 
leaves are of the normal form, while the remainder of the 
plant is composed of an ovate organ of the same texture 
as the leaf, but continuous throughout except for a small, 
irregular opening at the apex through which a younger leaf 
is visible. The first impression was that the structure in 
question consisted of an ascidium formed by the fusion of 
two leaves as has been described for Crassula arbores- 
cens,* but Mr. Thompson, upon 
looking through the rather large 
series of young plants then grow- 
ing, found two interesting forms, 
one of which is represented in 
figure 4, which were cultivated 
under the names G'. verrucosa 
and G. trigona. These seem to 
show a folding inof one or both 
margins of the leaf in a way 
which might indicate that the eg SRE ah + 
open calyptra originates from a single leaf developing 
from a primordium extending entirely around the vegetative 
point of the axis. In these two cases the tip of the leaf 
exhibits two apiculae and the same is apparently true for 
the plant represented in figure 1, though here the irregular- 
ity of the opening at the apex precludes a final decision. 
A transverse section near the 
base of the ascidium shows it to 
be composed of a layer of tissue 
slightly thicker on one side, sur- 
rounding two leaves of normal 
form, but not of the normal 5. G. BRacHYPHYLLLA, X 1. 
distichous arrangement, as may be seen from the diagram, 
figure 5. This anomaly of the leaf arrangement cannot 
be regurded as having any special significance since it is 
frequently to be observed in otherwise normal individuals 
* Morren, C. Bull. Acad. Roy. Sci. Belg. 19°: 458-462. pl. 1852. 
