1881.] NATURAL SCIENCES OF PHILADELPHIA. 441 



them. But there Avas one great difference in the genus, at least 

 as represented by these two species. In opening tlie box which 

 contained the specimens, the whole mass was covered with a 

 dense viscid secretion, which rendered it very difficult to separate 

 one branch from another. On leaving the lid open a little while, 

 the watery particles soon evaporated, leaving a dry gummy 

 deposit over the whole surface. While this was going on, the 

 seeds were ejected with great force from their endocarps. being- 

 projected against the face with such force as to leave a stinging- 

 sensation. Dr. Engelmann has noted this power of ejection in 

 the berries of this plant. The Phoradendron exhibited no trace 

 of any such power, though there seemed to be little difference in 

 the structure of the berries. The facts raised a nice teleological 

 question. Birds did not seem to use the berries. As they were 

 so viscid that the famous bird-lime is made from some species, 

 it is |irobable the very visciditv would prevent the free use of the 

 beak in any attempt to use the seeds. But it was believed that 

 by becoming attached to the feet or feathers of birds, the seeds 

 were widely distributed, and that in this w^ay the plant had all the 

 advantage necessary for distribution in the " struggle for life." 

 But Arceuthohiuni^ besides all the advantages to be derived from 

 this mode of distribution, had an additional aid from a projecting 

 force. 



Did Ai'ceuthobium at one time exist when or where tliere were 

 no birds, and hnd it to depend on projection alone for its dis- 

 tributing power, and is the viscidity a later development ? Did 

 Phoradendron once possess the power, and has it abandoned it 

 from having through the ages found out that it travels well 

 enough without its exercise ? Or is it rather, as the speaker him- 

 self inclined to believe, that nature loved to aim expressly at 

 variety, and was continually exhibiting her power to accomplish 

 the same end by a wonderful variety of means ? But whatever 

 might be thought of the various theories of development, and 

 the laws of final causes which may have operated to produce 

 changes, there could be but little doubt but parasitism was an 

 acquired habit, and the endeavor to find out what these plants 

 w^ere, and how they behaved before they were parasites, was fast 

 becoming one of the most interesting of biological studies. 



The seeds ejected from the endoearp in Arceidhobium fastened 

 themselves to the branches of trees b}^ a glutinous mass at one 

 end. This end was opposite to the radicle, which, in germinating, 

 w'ould have to push out from above, and curve downwards towards 

 the branch in order to attach itself. He had not seen them during 

 the process of germination, but as the testaceous covering was 

 held fast by the glutinous secretion, it is probable the cotyledons 

 would be drawn out as the plumule took its upright position, 

 leaving the testa as an empt}^ case fastened to the branch. Pre- 

 suming that this must be the case with other Loranthaceous 

 plants, it was difficult to imderstand the process by which the 



