1808] CURRENT LITERATURE 371 
entirely vegetatively. No zoospores have ever been seen, the supposed obser- 
vations of Montagne and Gardiner apparently having beén erroneous.— 
BRADLEY M. Davis. 
AT THE MEETING of the Academy of Science of St. Louis on the evening 
of October 17, 1897, Mr. C. H. Thompson spoke of some interesting stylar 
movements of certain Marantacez connected with their pollination. In the 
course of his remarks Mr. Thompson said : 
“Generally speaking, the flower of Marantacez is a more or less evident 
tube, with the calyx and corolla inconspicuous and the stamens changed into 
irregular petaloid staminodia, except a single fertile one. My studies of the 
order have been confined to three genera, Maranta, Calathea, and Thalia, 
and refer to about eight or ten species. In all of the species, one of the 
staminodia is developed into a keel-like structure, not unlike the keel of a 
papilionaceous leguminous flower. At maturity of the flower, this keel holds 
within its fold the style. On one margin of the keel, about midway between 
the apex and the base of the staminodium, is developed a tentacle-like body 
which is extremely irritable. This tentacle, in the open flower, guards the 
passage to the nectary. If the tentacle is irritated, the impulse is conveyed 
to the sheathing basal portion of the keel, which holds the style, opening the 
sheath and allowing the style to escape its embrace. This movement of the 
style is probably due to the unequal turgescence in the cells between those of 
the upper side and those of the lower side of the style, the greater turgescence 
existing in the latter. This, when the style is liberated, causes it to curve 
upward with considerable force. In Maranta the style forms a semicircle, 
coming to rest with the stigma firmly pressed against the upper staminodium, 
In Calathea and Thalia it makes a complete spiral revolution, bringing the 
stigma, in the former, into firm contact with the style, and in the latter placing 
it securely ina pocket formed by a fold of the inner wall of the upper stam- 
inodium. In each instance, the contact is so secure that the stigma can be 
reached only by destroying the flower. The sensitive tissues seem to be 
located in the outer cell structure of the sheathing base of the keel. An 
irritation from an outside agency directed against the tentacle is conveyed by 
that organ to the sensitive tissue, causing the sheath to open, and liberating 
the style, which it has been holding under great tension. 
“This complicated differentiation of the flower is undoubtedly an adapta- 
tion to insure cross-pollination. To understand this better, a detailed descrip- 
tion of the essential organs is desirable. In the flower bud the stamen lies 
parallel with the pistil, with its one-celled anther placed just back of the 
stigma and on the style. Immediately preceding the opening of the flower, 
the anther dehisces, shedding its pollen on a viscid disk which is located on 
= Style at the point of contact. Here the pollen adheres till scraped away 
in the operation next to be described. 
