io6 Harshberger — Statistical Information Concerning the 



The numbers marked by an asterisk show us, that as 

 respects the number of seeds contained in any given capsule 

 of a plant, the result of the act of fertilization has not been so 

 successful. 



Xanthium canadense, Mill. — A count was made of the 

 fruits of a plant (zw. echinatum) at the seashore in sand 

 which showed five well-developed fruits, and a plant growing 

 in gravel near Philadelphia, which had 622 fruits. 



Yucca filamentosa, L. (Adam's Needle). — This liliaceous 

 plant is of considerable interest from a biological standpoint 

 owing to its dependence upon the moth, Pronuba yuccasella, 

 Riley, which passes part of its larval existence in the capsule 

 of the plant feeding upon the seeds. The moth, previous to 

 depositing its eggs in the soft ovary, pollinates the stigma by 

 placing a ball of pollen from the same flower between the three 

 stigmatic lobes. This insures the production of good seeds 

 on which the larvae feed. The following table gives the 

 number of circular holes drilled by the larvae in leaving the 

 capsule to descend to the ground, the number of good seeds, 

 the number of seeds devoured by the larvae, and the number 

 of abortive seeds. There are two rows of seeds in each of the 

 three locules of the capsule ; a false partition present gives the 

 impression that the capsule is six-celled. The fruit vessel is 

 usually constricted in the middle through the irritation caused 

 by the puncture m.ade by the parent moth, so that it becomes 

 more or less dumb-bell shaped. In the enumeration, the two 

 rows of seeds in each cell are designated first side, second side. 

 The ratio established is that of the fully formed, black seeds 

 to the abortive seeds. By adding the seeds of normal appear- 

 ance of the first two columns, lettered first and second sides, 

 and subtracting the number of seeds devoured as well as the 

 bad seeds of normal form not given in the table from the sum 

 thus obtained, the figures for the last column of the table were 

 obtained, giving the number of seeds capable of germination. 

 Eight capsules were examined September ii, 1894, and the 

 results tabulated, as follows : 



