GERMINATION AND GROWTH 41 
develop at such different rates that it will probably not be necessary to 
make more than two plantings of each sort, from 2 to 5 days apart. 
Soaked seeds of corn and wheat will germinate in from 3 to 7 days, 
according to the temperature; oats in 1 to 4; beans in 4 to 6; 
squash and castor beans in from 8 to 10. Very obdurate ones may 
be hastened by clipping. Keep the germinators in an even temperature, 
at about 70° to 80° F. 
Pine is a very difficult seed to germinate, requiring usually from 18 to 21 
days. By soaking the mast for twenty-four hours and planting in damp 
sand or sawdust kept at an even temperature of 23° C. or about 75° F., 
specimens may be obtained. 
36. Seedlings of monocotyls.— Examine a seedling of 
corn that has just begun to sprout ; from which side does the 
seedling spring, the plain or the grooved one? Refer to your 
sketch of the dry grain and see if this 
agrees with the position of the embryo as 
observed in the seed. Make sketches of 
four or five seedlings in different stages of 
advancement, until you reach one with a 
well-developed blade. From what part of 
the embryo has each part of the seedling 
developed? Which part first appeared 
above ground? Is it straight, or bent in 
any way? In what direction does the 
plumule grow? The hypocotyl? Does the 
cotyledon appear above ground at all? Slip 
off the husk and see if there is any differ- ee et 
ence in the size and appearance of the (‘ling of corn (after 
contents as you proceed from the younger a geeahins oe 
to the older plants. How would you ac- _ later stage. 
count for the difference? 
37. The root. — Examine the lower end of the hypocotyl 
and find where the roots originate ; would you say that they 
are an outgrowth from the stem, or the stem from the root? 
Observe that the root of the corn does not continue to grow 
in a single main axis like that of the castor bean, but that 
numerous adventitious and secondary roots spring from 
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