Dec., 1902.] 
Observations on the Dandelion. 
335 
during another. No. One never grew one inch during am- day- 
time except once ; No. Two lengthened one inch in one daytime 
and two inches in one other. No. One lengthened rapidly during 
the last three days and nights just before it completed its growth. 
No. Two did the same, except that it grew an eighth of an inch 
after the seed had been scattered, probably owing to a shower. 
No. One did not grow any for three days and nights just before 
opening the head of pappus, but the weather was cold and rainy ; 
No. Two lengthened very rapidly during the three days and 
nights just before scattering the seed, probably because the* 
weather was warm and windy, with a slight shower the night 
before the head opened. No. One did not grow any during the 
three days and nights just after blooming, probably because its 
strength had been exhausted in flowering; No. Two did the 
same. This was the longest period of rest from growth that 
either plant took. The scape of No. One grew over an inch 
during the days and nights the head was in bloom ; No. Two, 
two inches. No. One grew one inch during the day and night 
just before blooming; No. Two, four and one-third inches the 
night previous to blooming — its most rapid growth. 
In No. One, previous to blooming, the scape bent over to 
lower and protect the head, but became erect the night before the 
head opened. By this process the head was elevated over an 
inch. No. Two did the same. Along the roadside this process 
often makes a difference in elevation of the head of four inches, 
especially if the neighboring vegetation is growing. After 
blooming the scape of No. One again flexed to lower and protect 
the head while the seed should ripen. By the scape’s assuming a 
compound curve the head stood erect. The scape became straight 
and vertical two days before the seeds were to be scattered, thus 
raising the head an inch more than it otherwise would be. Along 
the roadside this change in the direction of the scape often 
elevates the head as much as six inches. The record for No. Two 
was the same as for No. One. 
In No. One the corollas died and dried in about five days after 
blooming, and at the end of three more the growing pappus 
stalks pushed them off ; for No. Two no record was made. In 
No. One the plant was five days in reflexing the scales of the 
outer involucre ; but after they were once down they never again 
became erect. The same was true of No. Two. In No. One 
the scales of the inner involucre curved outward near their middle 
to permit the flowers to bloom, but became erect in the evening 
and at night to close the flower. They also remained erect while 
the seed was ripening. When the head of pappus was ready to 
come out this was accomplished by the receptacle’s changing from 
a concave disk to a convex one. This mechanical device not only 
opened up the head of pappus, but reflexed the involucres at 
