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DRAW a single haustorium showing the type of cells in the center and 
at the ends; the connection of the host and the dodder. Toward autumn 
flowers may be developed on the dodder vine. 
Study a fruiting branch of the dodder and oBsERVE:— 
20. The compact flower-clusters. Where do they seem to be 
most commonly formed? How many flowers in a cluster? 
21. Under the hand-lens, the scale-like leaf at the base of each 
flower-cluster and at the base of each flower. 
DRAW a single flower-cluster enlarged three times. 
Dissect and study a single mature flower. NOTE:— 
22. The structure and arrangement of the calyx, corolla, sta- 
mens with fringed scale at the base of each, and the pistil. How many 
parts of each? Draw a single flower enlarged, with calyx and corolla 
removed at one side. 
Cut across the ovary, examine with hand-lens and DETERMINE :— 
23. How many carpels and ovules are produced. DRaw. 
Examine the matured capsule. How.does it compare in size with the 
flower? How many seeds does it contain? Note the remnants of 
the calyx or the corolla at the base. From what does the capsule develop? 
DRAW. 
Saprogenests. The seeds fall to the ground where they lie dor- 
mant until the following spring. They germinate when conditions favor- 
able to the growth of the host prevail. The vestigial root serves as an 
anchorage for the simple slender seedling, probably taking up only water 
from the soil. The seedling seems to be dependent largely on food 
stored in the seed, although chlorophyl is slightly developed. Seed 
germination and contact of the seedling with its host completes the pri- 
mary life-cycle. 
Secondary Cycles may be initiated during the growing-season by 
pieces of dodder stems broken off in cutting and harvesting the host, and 
falling upon healthy plants, infecting them. Pieces of dodder stems are 
very tenacious of life and thus afford a dangerous inoculum for spreading 
the pathogene in cultivated crops. The spreading of the pathogene from 
one individual host-plant to a neighboring one may also be regarded as a 
type of secondary infection. 
REPORT 
1. A farmer had a few spot-infections in an alfalfa field. After 
cutting the hay, the ground where the dodder occurred was spaded. Soon, 
however, the dodder appeared about the margins of the same areas. 
Write a letter outlining the measures to be taken to prevent further 
local spread of the pathogene and its dissemination over the field. 
2. Give directions for determining whether or not there is 
dodder in the alfalfa seed, and if present, how to get rid of it. 
