1885. ] Botany. 887 
twenty of the characteristic spots, varfing from a tenth to a quar- 
ter of an inch in diameter. The petioles and partial petioles were 
frequently greatly distorted and enlarged, and in many cases the 
young twigs were swollen out into rounded nut-like growths 
which were covered with the tubular A®cidia. 
The injury produced by this rust in Lincoln was quite consid- 
erable, as green ash trees have been very largely planted along 
the streets for shade and ornament. These planted trees appear 
to have suffered more than the native ones along the streams, 
although the latter were by no means free from the parasite. 
I have as yet been unable to obtain any clue to the further de- 
velopment of the ash rust. One would look for a correspondingly 
great growth of red and black rust upon some of the plants of 
this region, but so far I have not observed any indication that 
such is the case.— Charles E. Bessey. 
THE FERTILIZATION OF THE WiLD BEAN (Phaseolus diversi- 
folius)—The flowers (Fig. 1) of the wild bean whén fresh are of 
a pretty rose-purple color, turning to a sort of dirty flesh color in 
fading. This change of color occurs at a time when insect visits 
are no longer necessary to the flower and no doubt serves to in- 
form the insect that it has no food to offer. The two wings are free 
from the keel but lie close to it; they furnish an alighting place 
Da 
2 
Fig. 2. 
Fic.—Flower of wild bean, seen somewhat from below. Fic. 2.—Keel and 
wings. Fic. 3.—Keef alone, showing lens-shaped base. Fic. 4.—Enlarged section 
of keel with style enclosed. Fic. 5.—The same with style projecting ; s¢, stigma; 
/. st, free stamen ; a, anthers of connected stamens. The dotted lines indicate the 
course of the united filaments. 
= middle-sized bees which visit it (Fig. 2). The keel itself 
the form of a vertically placed lens at its base, narrowing 
above into a narrow tube, which encloses both stamens and styles ` 
(Fig. 3). The anthers lie about the hairy end of the style and 
their pollen upon it. After this has escaped the free ends of 
the filaments shrivel up and allow the somewhat freer movement 
of the style. The anthers never leave the keel. Nine of the 
stamens are united by their filaments, but the tenth is free, In 
