13 
The seedlings of this species and of Amérosia germinated very 
promptly in the spring. The cotyledons are oblong, petioled. 
Hypocotyl long, bearing a few roots at its union with the tap-root. 
Branches developed from the axils of the cotyledons as well as 
the succeeding leaves, thus early determining the diffuse character 
of the mature plant. The first pair of leaves sparingly toothed, 
longer petioled than the cotyledons. The later leaves longer 
petioled and less sparingly toothed. The plant is an annual. 
Cnicus arvensis (L.) Hoffm. (Plates CKXXVII. B.C. D.) Seeds 
are not produced in abundance in the vicinity of Ithaca, yet 
by a little search plenty can be found. They have a long 
plumose pappus, are smooth and only obscurely angled. 
The seedlings with which this obnoxious weed begins its life 
history are innocent-appearing enough. The cotyledons although 
very like those of C. lanceolatus and C. muticus are very small. 
The first leaf is spiny on the margin, the succeedings ones be- 
coming larger and more spiny. Roots are given off throughout 
the length of the hypocotyl. The cotyledons have no prominent 
mid-rib; they are ovate, fleshy and obscurely reticulate-nerved. 
The early leaves are in a rosette. 
Arctium Lappa, L. (Plate CXXXVIII. A-F.) The akene of the 
~ Burdock is flattened parallel to the faces of the cotyledons. 
The pappus is about one-half its length and is deciduous. It 
is black and blistered. The hypocotyl in the seed is very 
short; the cotyledons are large, filling the greater part of the 
seed. 
The seedling is rather large, and, like the mature plant, very 
tenacious of life. The hypocotyl is short, only about one-fourth 
the length of the tap-root, and one-half as long as the coty- 
ledons, Prior to the development of leaves from the plumule, 
the tap-root branches very sparingly, and mostly at the point of © 
union of root and hypocotyl. It evinces a disposition from the first _ 
to become thickened. The cotyledons are sheathing at the base, 
fleshy, oblong-spatulate, obscurely emarginate, pinnately nerved, 
the lateral nerves visible only after the tissue has been cleared by 
Soaking in alcohol. Plumule not developed sufficiently to pro- 
trude from the sheathing bases of the cotyledons. The seedling : 
even at this pes ates emits the pau aad of the mature epee 
