

192 



wide field in structural organography touching upon economic and 

 horticultural questions. We commend the outline to teachers. 

 Cypress Knees, — Since sending you my note, (p. 137), P^o- 



■ y 



fessor Shaler has recorded that young trees appear in water- 

 covered districts where it is evident a tree from seed could not 

 have sprung. The suggestion Is made that such trees may have 

 sprung from fallen branches rooting in the water and mud. 

 Those versed in the propagation of evergreens could not admit 

 this. All experience is against the power of this class of coni- 

 fers to push out roots from mature wood, though many will 

 from half-mature wood, or cuttings from the same season s 

 growth. The fact, however, that young trees do appear in places 

 w^here a seed could not sprout and successfully grow to a young 

 tree, as recorded by Prof Shaler, is a valuable contribution to 

 our knowledge. It accords better with the English suggestion 

 that the '* Knee *' is an abortive sucker, than a rooted branch. 

 The arrested growth may be so accelerated as to become a true 

 tree trunk in some instances, just as the branch arrested to make 

 a larch cone, a pear or a rose, will sometimes be so accelerated 

 as to produce another growth from the axis, as is constantly the 

 case in the pineapple. But the '' rooting branch " hypothesis 

 of Prof Shaler, or the " arrested sucker " of the anonymous 

 English writer, ought to be easily confirmed by those who are 

 in the vicinity of a Cypress swamp. Some evidences of these 

 transition stages should surely exist. 



The subject has a broad interest. Should it be proved by 

 actual evidence that the " Knee " of the Tax odium is an abortive 

 sucker, w^e shall all want to know how an abortive sucker becomes 

 hollow, and the answer cannot but have a great value in vege- 

 table physiology, and kindred branches of the science. 



Meehan 



Knees mentioned bv M 



Bulletin for May, I would remark that this tree will certainly 

 make "knees " on high land. They are, however, not so prom- 

 inent as in the overflowed swamps, since they do not have to 

 project so far to reach the light and air. They certainly do not 

 always have tap roots below them, for I recollect that in the 

 grounds at " Hampton," near Baltimore, in an out-of the-way 



