1912'] Live Oak and White Oak Seedlings 35 



swells up at once, while the developing plumule forces its waj up 

 through a slit in the base of the stalk. It seems that the danger 

 of losing connection with the storehouse of the cotyledonous 

 mass through the long and slender passage of the stalk, necessi- 

 tates the transfer of the food-matter to a nearer and safer place 

 of deposit. But whj, it may be asked, is the connection so 

 much longer and more slender than in the other oaks? At all 

 events it suffices, so long as it is fresh and unimpaired, to carry 

 over in a very short time the starchy and sweet contents from 

 the cotyledons to the tuber; and before the ascending axis is 

 an inch high and bears as yet only a few minute bracts, the 

 tuber is already forming and it soon reaches the size of the 

 cotyledons themselves ; it is, however, longer and more slender, 

 of a fusiform shape, about three or four lines thick and one or 

 two inches long, attenuated below into the long tap-root." 



"The whole process is similar to the germination of the 

 cucurbitaceous Magarrhiza of California, so beautifully illus- 

 trated by Gray in his structural Botany; with this difference, 

 that the cotyledons in that plant are raised above the ground,^ 

 while in ours they remain hypogaeous, and that the stalk is 

 even longer, and is, together with the cotyledons, readily sep- 

 arable into its two component parts. In both plants a tuber 

 forms at once by the transfer of the food-matter from the coty- 

 ledons to the radical; in the herbaceous Megarrhiza the tuber 

 becomes a permanent organ of immense size, while in the ar- 

 boreous live-oak it is finally merged into the root." 



It may be of interest, also, to give two of Dr. Engelmann's 

 letters to Mr. Mazyck (not before published), in which this 

 subject is referred to. On March 10th, 1880, he writes: 



"Wm. St. J. Mazyck, Esq., 



Dear Sir: — You will find from a little paper which I pub- 

 lished in the St. Louis Academy Transactions, and which I 

 will send in a few days, that I studied not only the germination 

 but also the structure of the acorn itself and find in it an inter- 

 esting character. 



- "But only exceptionally" is the foot note at this point by the editors of 

 Dr. Engelmann's collected works. 



