RED-CLOVER SEED PRODUCTION. yi 
alee are pressed downward and the stigma and anthers are thrust up 
against the bee’s head. Since the carina and stamens are elastic, the 
pollen is thrown with considerable force against the head of the bee. 
When the bee releases the pressure on the carina and ale, the parts 
return to their normal position on account of the elasticity of the 
base of the carina and a small dilated vesicular process at the base 
of each ala. (Fig. 1.) 
LENGTH OF THE COROLLA TUBE OF RED-CLOVER FLOWERS. 
The corolla tube of red clover is stated by Knuth (22, v. 2, p. 289) 
and Miller (29, pp. 184-186) to be from 9 to 10 millimeters in length. 
Pammel and King (32) report an average length of 9.4 millimeters 
for 450 flowers. Schachinger, according to Fruwirth (12, pp. 163- 
166), says the corolla tubes are shorter in the second crop than in 
the first crop, and for this reason smaller bees are able to work on the 
second crop than on the first. 
Fifteen corolla tubes from each of 28 heads of first-crop red clover 
were measured at Ames, Iowa. The greatest variation found in 
different flowers of the same head was 2 millimeters. The 420 
corolla tubes varied from 8.5 millimeters to 11.5 millimeters, with 
an average length of 9.6 millimeters. 
DEVELOPMENT OF THE FLOWERS OF RED CLOVER. 
The stamens of red clover devetop much more rapidly than the pistil, 
and the length of the longer set exceeds that of the pistil until near 
the time the flower opens. The pollen is formed in the longer stamens 
through the division of the mother cells when the pistil is about 0.25 
millimeter in length. The division in the pollen mother cells of the 
shorter stamens closely follows that in the longer stamens. When 
the pistil is about 1 millimeter in length, only about one-twelfth of 
its length at maturity (fig. 2, A), the pollen grains are apparently 
mature so far as their size, their shape, and the thickness of their 
walls are concerned. At this stage the two ovules are well formed, 
but the egg and endosperm cells are not developed till later and are 
not ready for fertilization until just previous to the opening of the 
corolla. The later development of the pollen consists in protoplasmic 
changes. After the pollen grains have reached their mature size and 
their walls have become mature the protoplasm shows very little or 
no granular nature. Just before the flowers open the protoplasm 
becomes very dense. At this stage the protoplasm contains much 
oil in the form of an emulsion. The pollen will now germinate. 
The pistil has a stylar canal reaching from the ovary almost to 
the stigma. Just previous to and during the opening of the corolla 
the pistil elongates more rapidly than the stamens, and as a result 
the stigma is usually pushed beyond the anthers in the open flower 
