8 
l iiK Colorado I^xpekiment Station 
injury than if they stood on erect stems, and it is difficult to cut 
them off with the laAvn-mower during this time. 
When the seeds are nearly mature, the flower stem begins to 
straighten up and at the same time elongates, thus lifting the 
ripened seeds into a better position for the wind to get at them. 
In some cases, this seed-bearing stalk lengthens to a remark¬ 
able extent. Thus, the writer found one plant growing in partial 
shade and among taller vegetation, which had a seed stalk 29 
inches tall. 
Careful examination of the dandelion bloom will show that 
it consists of many very minute flowers crowded into a dense clus¬ 
ter at the upper end of the flower stalk and surrounded by two 
sets of narrow green bracts. The number of these little flowers in 
one blossom head varies greatly according to the size and vigor 
of the plant which bears them. Thus, the lowest number, 30, was 
counted in a blossom head from a small, stunted plant, while one 
of ordinary size was found to contain more than two hundred of 
the minute flowers, each capable of producing a single seed. The 
bracts of the outer or lower set turn downward, while those of the 
inner set form a close covering for the little flowers when not in 
bloom. 
When about to bloom, these covering bracts spread apart and 
expose the crowded mass of tiny yellow flowers inside. Toward 
night the bracts close together but open again the next morning. 
In this manner the flower heads open during two or three suc¬ 
cessive days, after which they remain closed until the seeds are 
mature. From the first day of blossoming until the seeds ripen 
and the bracts open for them to escape, nine or ten days usually 
elapse. 
Pollination of the Flower ,—This consists in the transfer of the 
yellow powder (pollen) from the stamens of the flower to the 
stigma or tips of the pistil which produces the seed. Without this 
transfer of pollen no seeds would be produced. In the minute 
flowers of the dandelion head this process of pollination may take 
place in two ways. First, the powder-like pollen grains are push¬ 
ed out of each little flower by the lengthening of the pistil during 
the process of blossoming. The two stigmas of each flower dur¬ 
ing this stage are closed in such a way that none of the pollen is 
apt to adhere to them from the stamens of their own flower. The 
crowded condition of the little flowers, however, almost insures 
the contact of the two stigmas, as they uncoil, with pollen from 
other flowers that are just opening. 
