398 : General Notes. [April, 
arrangement, pollination would easily take place. The back of 
the anthers and the entire surface of the little tips extending 
above them are hairy. So are likewise the styles (Fig. 3). The 
calyx is closely contracted at its opening, pressing together the 
numerous stamens and pistils into a compact mass. Owing to 
the greater size of the pistils, the stigmas extend beyond the an- 
thers (Fig. 4), and since the close packing brings the hairs on the 
Fig. I. Fig. 2. Fig. 3- Fig. 4 
Fic. 1.—A flower, natural size, Fic. 2,—A stamen enlarged 1% times; a, the 
anther; 7, the nectary. Fic. 3.—A pistil enlarged 114 times; o, the ovary; s¢, the 
44 a “i 
stigma; Fic. 4—A pistil and a stamen about natural size, showing relative length, 
anthers into play, the pollen does not escape. But at a later 
period the pressure of the sepals relaxes, the stamens are looser, 
and self-fertilization is not absolutely impossible, but certainly un- 
necessary, judging by the frequent visits of bees. The insertion 
of the bee’s proboscis releases the pollen, which falls upon the 
abdomen and thorax, to be left upon the more prominent stig- 
mas of the next blossom. The nectary is at the base of the fila- 
ment.—Aug. F. Foerste, Granville, Ohio. 
Prant Micrations.—Fifteen years ago there were no dande- 
lions in the Ames flora (in. Central Iowa), now they are very 
abundant, and have been for half a dozen. years. Then. there 
were no mulleins (Verbascum thapsus), now there are a few. Then 
the low and evil-smelling Dysodia chrysanthemoides grew by the 
roadside in great abundance, now it is scarcely to be found, and 
is replaced by the introduced “ dog-fennel” (Arthemis cotula). 
Then the small fleabane (Erigeron divaricatum) abounded on dry 
soils, now it is rapidly disappearing. Then no squirrel-tail grass 
(Hordeum jubatum) grew in the flora, now it is very abundant, 
and has been for ten years. Then there was no bur-grass in the 
flora, now it is frequently found, and appears to be rapidly increas- 
ing. Both of these grasses have apparently come in from the 
west and north-west. Fifteen years ago the low amaranth (Ama- 
vantus bvitoides) was rather rarely found; now it is abundant and - 
_ has migrated fully 150 miles north-eastward. This plant has cer- 
=~ tainly come into the Ames flora from the south-west within the 
last twenty years. 
In Nebraska, I am informed by the old settlers, that there have 
been notable migrations of plants within the past twenty or thirty 
=~~ years. The buffalo grasses of various kinds were formerly abun- 
