founded on the Structure of their Seedlings. 45 
from the cotyledon. They rarely affect the symmetry of the 
root-stele, which is commonly triarch. It depends on the 
central trace from the cotyledon, and a lateral trace on either 
side of it. Each of these lateral traces is formed by the 
fusion of a pair of lateral bundles. The transition takes place 
according to Van Tieghem’s type 3. The xylem groups are 
continued straight downwards, the protoxylem becoming 
external on the way, and each phloem group divides, the 
right-hand segment of one uniting with the left-hand segment 
of the next. 
Nothing in the vascular symmetry of Arum suggests a 
relationship with any Liliaceous type. All that can be said 
is that the possibility of such relationship is not excluded. 
The seedling of Arum maculatum is hardly more unlike that 
of Anemarrhena in its vascular structure than is that of 
Veratrum , for instance. 
The seedling of Arisaema speciosum resembles that of 
Arum in many points. The tuber is already formed very 
shortly after germination, and the first green leaf makes its 
way out of the cotyledonary sheath early in the first season 
of growth. The cotyledon contains seven or nine bundles, 
and the primary root is either triarch or tetrarch. 
Anthurium Baker ianum differs completely from the genera 
just described both in the external form and in the internal 
structure of its seedling. The cotyledon remains underground 
— its apex enclosed within the endosperm of the seed. The 
petiole of the cotyledon is short, and its base is expanded 
into an open sheath which shelters the plumule without en- 
closing it. The first leaf develops early. It breaks through 
the soil and becomes green, while its base sheathes the 
younger leaves and the growing point. They are thus safely 
packed between the cotyledon and the first leaf. 
Sections through the apex of the cotyledon as it lies 
within the endosperm show two bundles within it. They 
unite before passing into the petiole, and the bundle which 
enters the sheath of the cotyledon is apparently single. During 
the transition, however, it opens out into a double bundle. 
