11 
base, strongly triple nerved. The first two leaves are nearly op- 
posite; the succeeding become more and more distinctly alternate 
until, as in the mature plant, they are of the alternate type. 
Seedlings, before the first leaves develop, have the hypocotyl 
bent nearly at right angles, thus causing its upper part and the 
cotyledons to lie upon the surface of the ground. At this stage of 
their growth there is every indication that the plant will be pros- 
trate. It very soon straightens up, however, and by the time the- 
first leaves are fully developed it is entirely erect. How the plant 
has come to assume this peculiar habit it is difficult to see. 
Anthems arvensis, L. (Plate CXXXVI. D.E. F.) Akenes roughly 
ribbed, not flattened, “crowned with a very short slightly 
toothed margin in place of a pappus.” 
Seedling with nearly sessile oblong cotyledons. Hypocotyl 
comparatively long. Tap-root evident. First two leaves pinnate. — 
The succeeding bipinnate. The change from cotyledons to lobed 
leaves is abrupt. 
The plant is a winter annual, that is from a plant ripening in 
July, seeds germinate the same autumn and remain over winter as 
seedlings. A. Cotula, L. (May weed) is, on the other hand, a 
summer annual. It ripens its seeds in autumn, and these do not 
germinate until the following spring and early summer. 
Chrysanthemum Leucanthemum, L. (Plate CXXXVI. A. B. C.) 
~ Akene small (2 mm. long by 34 mm. wide) 8 to 15-costate. 
The costa white, the intervening spaces black. Pappus none. | 
Cotyledons of seedlings small, short-petioled, the petioles 
united at the base into a short sheath; blade oblong, thick. First 
two leaves spatulate, entire, borne on petioles nearly as long as the 
blade. The later leaves are like the radical leaves of the mature 
plant. The first and second leaves in this species can hardly be 
said to be intermediate in form between the cotyledons and the 
succeeding leaves. 
Achillea Millefolium, . (Plate CXXXVI. G. H. J-) Akene ob- 
compressed, margined, small. The margin white; pappus none. 
Cotyledons small, nearly orbicular, closely sessile. First two 
leaves small, tridentate, or the second one with two pairs of lat- 
eral leaflets. Succeeding leaves like the leaves of the mature 
plant. 
