8 Esther Pearl Hensel 



than the inner, and the flower closes, or, in the case of flowers 

 remaining- open at night, meteoric influences aflfect the internal 

 and external surfaces in the opposite way. 



It is due to Anton Hansgirg, first in 1S90, and then later, that 

 we have such exhaustive lists of plants possessing what he calls 

 "gamotropic" and "carpotropic" movements, principally the lat- 

 ter. Under the former term he includes movements that serve 

 to protect the ovary and stamens and to make cross-fertilization 

 easy ; under the latter, those growth movements of flower stems 

 by which the flower is placed in a certain position at one period 

 of its growth, and in a different one at a later period ; for ex- 

 ample, the morning glory bud and flower are erect, while the 

 fruit is pendulous. Movements of the calyx, involucre, etc., to 

 protect the fruit, are also included under "carpotropic" move- 

 ments. The real cause of what he terms "gamotropic" move- 

 ments, those serving to protect the ovary, stamens, etc., he does 

 not state directly, but in a later paper he remarks that carpotropic 

 nutation movements are not so dependent upon the daily change 

 of light as the nyctitropic and gamotropic appearances. He also 

 makes the statement that carpotropic movements must be distin- 

 guished from those similar to nyctitropic and gamotropic ones 

 which occur through epinasty and hyponasty — the merely passive 

 movements without growth. In a still more recent article (1892) 

 he adds a few facts on the subject, but offers no explanation, 

 saying that it is yet to be proven whether periodic opening and 

 closing are caused by changing epinastic and hyponastic growth 

 of flowers. He states that such movements are inconstant in 

 different genera of the same family. The same lists of species 

 were continued in 1896 when he assigned to gamotropic and to 

 nyctitropic movements light and heat as causes. He divides 

 gamotropic flowers into: (a) those periodically opened and 

 closed, (&) ephemeral, day or night, (c) those that open only 

 once and stay thus until withering (agamotropic), and {d) those 

 that are pseudocleistogamous and hemicleistogamous. Light is 

 given importance, for ephemeral flowers can be made to become 

 two-day flowers if deprived of light. In 1902 still further addi- 

 tions were made to these lists of species possessing types of car- 



198 



