1886.] natural sciences of philadelphia. 291 



July 6. 

 Mr. UsELMA C. Smith in the chair. 

 Seven persons present. 



July 13. 

 Mr. Thos. Meehan, Vice-President, in the chair. 

 Ten persons present. 



On Torsion in the Hollyhock, with some observations on cross- 

 fertilization. Mr. Meehan observed that the torsion of the 

 opening flowers of the hollyhock was towards the sun ; but after 

 the expanded flower had become fertilized, and the flower closed 

 for fading, the torsion was in the contrary direction. The same 

 thing occurred in Hibiscus rosa-sinensis. He had no opportunity 

 to this date to note the facts in other Malvaceae.^ As a general 

 rule the spiral revolutions of plants are uniform through every 

 stage of growth, at least this is the general teaching of botanists. 

 Prof. Goodale notes (" Bot. Text Book," vol. ii, p. 407), that in 

 the Tropics, some plants twine indifferently from right to left. 

 If we had given thought to the manner in which secund inflores- 

 cence is arranged, we might have seen that the torsion is anything 

 but uniform throughout the same plant, for a secund raceme 

 could only be formed by the twisting of each succeeding flower 

 in an opposite direction. This alternation of convolution is 

 indeed necessarj' in a branch with a horizontal direction in order 

 that each flower along the spiral should assume an erect attitude. 

 When a horizontal or geotropic branch assumed an upright posi- 

 tion, the inflorescence was necessarily secund. One might almost 

 infer that secund inflorescence had its origin in geotropic plants 

 which had retained the power of alternate torsion after assuming 

 the erect form. So little is known of the laws operating in 

 connection with the turning habits of plants and flowers, that 

 every fact is of value, and this one relating to the reversal of the 

 direction in these two malvaceous plants, and probably in others 

 of the same order, must be worth placing on record. 



Mr. Meehan farther noted that the hollyhock, notwithstanding 

 its gaudy coloring and general attractions to insects, is a self- 

 fertilizer, and that insects I'ather aided than otherwise in this 



^ The author has since noted that in Palava flexuosa the flower twists 

 also in the direction of the sun, and in the contrary direction when fading, 

 but in Gallirhcea involucrata the flower is twisted against the sun, when 

 fading as when opening. 



