IN FERTILIZING PLANTS. 259 
In the Evening Primrose (Oenothera glauca Michx., 
Oe. Missouriensis and linearis Michx.), the stigmas pro- 
ject beyond the anthers, and the flowers vary from an erect 
to a horizontal position.’ There are four large stigmas for 
each style, spreading in the form of a Greek cross. 
The pollen, slightly held together by delicate threads, 
is collected in the morning by great numbers of small 
wasps, about two-thirds the size of honey-bees. I have 
often watched them while coming down on, or just over, 
the stigmas, leaving pollen as they went in, and after col- 
lecting what they could, fly out at the side without touch- 
ing the stigma. On one of these plants, at two different 
times, a wasp was eagerly trying to pick up the pollen 
which had been left on the stigmas; the more they tried 
to collect, the more they scattered pollen about on the 
glutinous surface, until, as if discouraged or disgusted, 
they rapidly cleaned their legs of all the tangled mass, 
and flew away, leaving that cluster of flowers entirely. 
In the flowers of the Pea, False Indigo, Yellow-wood 
(Cladastris), Red-bud or Judas-tree, Red and White 
Clover, Locust, and others of this large and important 
family (Leguminose), the anthers surround the stigma, 
and are closely covered by the corolla. This certainly 
looks like a very clear case for self-fertilization, but I 
doubt not the reverse is very often the case. Many 
of the flowers, as the Pea and Locust, have one petal 
much larger than the rest, called the standard or banner. 
Opposite this is another part composed of two petals 
Sometimes united, termed the keel. On this keel bees 
uniformly alight, and crowd the head down next to the 
banner-petal. To enable them to do this, they kick 
keel and side petals (wings) with their hind legs, 
nd push them back so that the anthers and stigmas 
stigmas 
