MACFARLANE: SYNCHRONISM IN PLANT STRUCTURES 323 
round Wilmington, N. C., it begins on April 18; in central New 
Jersey, it opens on the 20th of May; in northern New York and 
Minnesota it blooms from the 14th to the 26th of June. In eastern 
central Maine the period is from the 8th to the 20th of July, while in 
Labrador—the northern limit of the species—it finishes in mid-August. 
Thus a period of fully five months is represented, and a longitudinal 
area of about 2,000 miles is covered, in the floral maturation of this 
one species. In connection with such records, and probably due to 
the more gradual and even expenditure of environal heat stimuli is 
the much more extended floral period of species in the cool north than 
in the warm south. Thus while the double Crimson Rambler and 
Dorothy Perkins roses show floral attractiveness from June 10 to 
June 25 averagely round Philadelphia, on eastern Mt. Desert the 
period extends from July 15 to August 30. 
Were the valuable records, inaugurated in 1892 for Canada by 
Mackay, to be linked up with like records from widely distributed 
stations in this country, and were all to be correlated with tempera- 
ture or thermotactic and moisture or hydrotactic stimuli, as has in 
part been done by the Canadian observers, a most valuable foundation 
for the establishment of facts regarding the action of definite environal 
stimuli would be made. 
A very wide field for exact study, still left practically untouched, 
is the observation and recording of sporangial ripening and spore 
dissemination in pteridophytic and bryophytic genera and species. 
One or two references need only be made here. 
For years the writer was puzzled to know when spore-dissemination 
took place in the sensitive fern (Onoclea sensibilis). Though the 
green sporophylls shot up in late July and became greenish-brown in 
autumn, opening of the modified pinnae and dissemination of spores 
clearly did not take place before winter. Passing through a swampy 
patch of this on March 24 of five years ago his clothes became browned 
over with the shed product. Subsequent study has shown that this 
event occurs averagely on March 25, and in any one patch or locality 
with surprising synchronous exactness. Like observations should be 
made for Onoclea Struthiopteris. 
The sudden and simultaneous elongation of the sporophores and 
the subsequent rupture of the sporangia in such hepatics as Pellia 
endiviaefolia is familiar to all in mid-April, but we still lack exact day 
and hour records through succeeding years for the entire group of 
scale mosses. 
The predicable manner in which, when fresh horse manure is 
placed under bell jars in the now familiar laboratory experiment with 
Pilobolus, an abundant crop of the black sporangia is shot forth on a 
