Trelease.] 
436 
[March 15, 
Close-fertilization is not necessarily impossible, though it does 
not seem to occur in cultivated plants, so far as my recollection 
goes. Some pollen falling spontaneously from the longer sta- 
mens, may drop on and among the viscid hairs on the door of the 
corolla ; or, as is not improbable, these hairs may remove some of 
the pollen from a retreating insect. In either case a jolt or suit- 
able stimulus, exciting the stigma to a second movement, would 
enable it to reach and remove some of this pollen. In the last 
suppositional case, close fertilization would be effected by insect 
agency, but only in case the insect had brought no pollen from 
other flowers and other insects had remained away. It will be 
seen that it differs only in complication from what happens when 
the first visited flowers of Primula, Ipomaea, etc., are not visited 
a second time. 
The irritable movement in Goldfussia was first studied in G. 
anisophylla by Charles Morren, who notices the irritable move- 
ment in a filiform stigma as something remarkable. His descrip- 
tion of the flower, and especially of its epidermal appendages and 
the intimate structure of the style, is very thorough. According 
to him the mechanical cause of the motion lies in the turgescencc 
of what he calls the cylindrenchyma of the stigma; this tissue 
being formed of long cylindrical cells, dilatable at either end, 
each filled with granular contents. These naturally collect at the 
exterior ends of the cells, which, dilating, curve the stigma into 
the form it assumes when undisturbed ; but when this organ is 
touched, the cell contents retreat to the bases of the cylinders, 
lengthening the upper side and causing the straightening or reflex- 
ion of the stigma. The physiological cause is held to be the 
excitability of the contents of these cells. 
Although his description of the parts and the phenomena is 
excellent Morren did not understand the significance of the 
movement, believing that it was to secure close fertilization by 
one of the modes I have already indicated. He found that 
although the long hairs impede their jwogress, ants succeed in 
entering the flowers in the greenhouse, and says : “ When they 
come out I have seen them carry pollen upon these hairs and 
excite by their movements those of the style. It is undoubtedly 
thus that fertilization occurs in this pretty plant, and there are 
few in which the part that insects play in the reproduction of 
