Vol. 2 No. 12 



TORREYA 



December, 1902 



VACATION OBSERVATIONS— II 



By Francis E Lloyd 



Propulsion of Gemmae in Lycopodium luciduhim. — Leavitt * re- 

 ports that the gemmae of L. luciduhim may be thrown to a dis- 

 tance of 3 to 4 feet. He induced the propulsion by pressing down 

 gently at the extreme edge of the cotyledon-like leaf of the 

 gemma. It is further suggested that in nature the gemmae must 

 be struck by some object such as a moving plant or animal, or a 

 rain drop, in order that the tension set up by the tissues of the 

 clasping organ may be utilized for the expulsion of the gemma. 



Having found a patch of gemmiparous plants at Northfield, 

 Mass., early in September, I was led to repeat the experiments 

 of Leavitt, at first by the method which he used, as above de- 

 scribed, a method which I had used earlier in the case of L. 

 Selago in the Austrian Tyrol. f It soon occurred to me, how- 

 ever, that there was a better way of doing it, possibly imitating 

 the condition in nature more closely, namely by pinching the gem- 

 miparous branch at its base in such a manner as to exert a slight 

 pressure upon the leaves which clasp the gemma. It became 

 possible in this way to set free the gemma without interfering in 

 any way with its flight. By holding the plant near the ground on 

 a level spot, so as not to give it any advantage of elevation, I 

 found that the maximum flight reached somewhat over three 

 feet, though in the majority of cases the range fell within fifteen 

 inches. The trajectory, moreover, is markedly curved, falling in 



* Leavitt, R. G. Notes on Lycopodium. Rhodora, 4 : 57-60. Mr. 1902. 



f Lloyd, F. E. Observations on Lycopodium. Torreya, 2 : 20, 21. F. 190 . 



[The exact date of publication of each issue of TORREYA is given in the succeed- 

 ing number. Vol. 2, No. II, comprising pages 161-176, was issued Nov. 25, 1902.] 



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