THE THREE FORMS OF LYTHRUM SALICARIA. 175 
Insects are necessary for the fertilization of this Lythrum, 
During two years I kept two plants of each form protected, and 
in the autumn they presented a remarkable contrast in appear- 
ance with the adjoining uncovered plants, which were densely 
covered with capsules. In 1863 a protected long-styled plant pro- 
duced only five poor capsules ; two mid-styled plants produced the 
same number ; and two short-styled plants between them produced 
only one: these capsules contained very few seed; yet the plants 
were fully productive when artificially fertilized under the net. 
In a state of nature the flowers are incessantly visited for their 
nectar by hive- and humble-bees and various Diptera. The nectar 
is secreted all round the base of the ovarium; but a passage is 
formed along the upper and inner side of the calyx by the lateral 
deflection (not represented in the diagram) of the basal portions 
of the filaments; so that insects invariably alight on the upper 
side of the flowers, on the projecting stamens and pistil, and insert 
their probosces along the upper inner margin of the calyx. We 
can now see why the ends of the stamens with their anthers, and 
the ends of the pistils with their stigma, are a little upturned, in 
order that they may brush against the lower hairy surfaces of the 
insects’ bodies. The short stamens which lie enclosed within the 
calyx of the long- and mid-styled forms can be touched only by 
the proboscis and the narrow chin of the sucking bee; hence they 
have their ends more upturned, and they are graduated in length, 
so as to fall into a narrow file, three deep, sure to be raked by 
the thin intruding proboscis. The anthers of the longer stamens 
stand laterally further apart and are more nearly of the same 
length, for they have to brush against the whole breadth of the 
insect’s body. I may here incidentally remark, that in very 
many flowers the pistil, or the stamens, or both, are rectangularly 
bent to one side of the flower: this bending may be permanent, 
as with Lythrum and many others, or may be effected (as in 
Dictamnus fraxinella and many others) by a temporary move- 
ment which occurs in the stamens when the anthers dehisce, 
and in the pistil when the stigma is mature; but these two 
movements are by no means always contemporaneous in the 
same flower. Now Ihave found no exception to the rule, that 
when the stamens and pistil are bent, the bending is exactly to 
that side of the flower which secretes nectar (even though there 
be a rudimentary nectary of large size on the opposite side, as in 
some species of Corydalis); or, when nectar is secreted on all 
LINN, PROC.—BOTANY, VOL, VIII. £ 
