162 PROCEEDINGS OF THE ACADEMY OF [1897. 



It appears probable that these runners with incipient plants or 

 bulbs on their tips, in many cases, appear regularly at certain sea- 

 sons, and their development may be confined to certain periods. I 

 observed the beginning of the formation of runners of Erythronium 

 in early April, and their subsequent development which lasted at 

 least until June, when bulbs had formed on the ends. The speci- 

 mens of Oxalis referred to above were collected in June, but I have 

 also found runners on the bulbs of this plant in October. My chief 

 reason for putting these few observations together is to direct atten- 

 tion to these points, since the time favorable for this line of work 

 will soon be at hand. Our spring flowers will, without doubt, prove 

 good objects for investigation. It seems reasonable to suppose that 

 the formation of runners will be found to be most active when the 

 plant is not requiring much energy in seed and fruit formation. 

 This certainly seemed to be the case with Erythronium. I do not 

 now remember having found any runners on plants in flower, but I 

 collected scores of plants which produced runners actively, but 

 which had not sent up their flowering scapes. 



The following is directly in this line : On the 26th of April of last 

 year I came upon a locality near Swarthmore which was overrun to 

 an unusual extent by Ariscema triphyllum. I was struck by the 

 marked difference shown by these plants so far as their respective 

 stages of development were concerned, and began to dig up speci- 

 mens of various degrees of maturity. Upon examination of a young 

 plant such as is represented in Plate III, fig. 1, the corm was just be- 

 ginning to swell, a number of roots had emerged from it; these were 

 clothed with root-hairs for the soil adhered to them tenaciously. One 

 might naturally conclude that these young plants were seedlings pro- 

 duced from the fruit of the preceding year. A different origin was, 

 however, suggested by other plants of about the same appearance and 

 stage of development. A clue was obtained by such specimens as 

 that represented by fig. 2. The corm was somewhat thicker and 

 the appendage at its lower end was very suggestive. This was 

 brown in color, and was, without doubt, what remained of a shrivelled 

 runner attached at one time to another plant. Upon examination 

 of still younger plants, figs. 3 and 4, no sign of a thickened 

 corm was to be seen, and the rootstock, if such it may be called, was 

 still firm and hard. The attachment to the mother plant was, how- 

 ever, no longer intact. 



