106 Peirce. — On the Structure of the Haustoria 
CUSCUTA GLOMERATA, Choisy. 
The plants of Cuscuta glojnerata examined were growing 
luxuriantly on Impatiens Balsamina , L. at the time that they 
were ‘ fixed ’ and preserved in alcohol. Their stems are 
smoother and slightly larger in diameter than those of 
C. americana. They twine from left to right about the foster- 
plant in spirals generally shorter and closer than those formed 
by the preceding species. The haustoria are larger but 
otherwise differ only slightly in origin, form, and structure 
from those already described. They are oriented in con- 
formity with the closer spiral made by the mother-plant. 
They consist of central cylinder and cortex, which latter is 
thickest at the base and is reduced to a single layer at the 
apex. The union of the conducting elements of the haus- 
torium with the corresponding elements in a bundle or in two 
bundles of the host is here also direct, as shown by Fig. 14, 
PI. XIV, and the connection between the conducting tissues 
of parasite and host is unbroken. Fig. 14, PL XIV, represents 
a section of a comparatively young haustorium which springs 
from a parasitic stem the long axis of which is inclined, as 
nearly as possible, at a right angle with the long axis of the 
plant about which it has twined ; hence the union of the 
haustorial conducting elements with those of the mother-plant 
is only partially shown. In this figure is also shown in part 
the bifurcation of the strand of xylem near the tip of the 
haustorium in order to effect a union with the xylems of two 
adjacent bundles. Furthermore, one sees what less often 
occurs in C. americana , at least when growing on the hosts 
which I have examined, namely the encroachment of 
haustorial cells upon the cambium of the bundle attacked, 
and the union of haustorial xylem- and phloem- cells in 
tangential, instead of radial, fashion with the xylem and 
phloem- elements of the bundle of the host (Fig. 14, t ). 
Owing to its softer, less closely compacted structure, 
Impatiens Balsamina presents fewer mechanical difficulties to 
the study of the cells of the tip of the haustorium in their 
