1889.] NATURAL SCIENCES OF PHILADELPHIA. 53 



CONTRIBUTIONS TO THE LIFE HISTORIES OF PLANTS. No. IV. 

 BY THOMAS MEEHAN. 



On Secund Inflorescence. So far as the author of this paper knows, 

 no explanation has been given as to why flowers are often secund 

 on the rachis. Sachs goes into the subject somewhat (Text Book of 

 Botany, English Ed., p. 189), but evidently without being clear in 

 his own mind as to the proper method of accounting for it, under 

 the prevalent conceptions of phyllotaxis. 



To those who have been able to examine many species of the 

 thick-stemmed Begonias, to which this author refers as having leaves 

 from one side of the stems only, it must be evident that they are but 

 herbaceous species that have learned to become erect. What are 

 thickened, creeping rhizomes in some species, have become ascending 

 upright stems in these shrubby ones ; and they have carried along 

 in this evolutionary movement the unilateral character of producing 

 the foliage, which must of necessity prevail in a procumbent stem. 



This change of the horizontal to the erect position is apparent in 

 many plants, especially in ferns. Tree ferns have no rhizomes, 

 because the trunk of the tree fern is itself but an erect rhizome. In 

 draining old swamps, the author has taken out old rhizomes of O-s- 

 munda regalis, many feet in length, and three inches in diameter, in 

 no way differing from the trunks of the smaller arborescent ferns 

 except a vertical tendency in the remains of the stipes. There are 

 instances on record where this fern has become wholly arborescent, — 

 that is to say, instead of producing the usual creeping rhizoma, the 

 rhizome has become erect. But whether that rhizome, when erect, 

 continued the lateral arrangement of its former position, as in the 

 allied case of Begonia, it did not seem to occur to the observer to note. 

 A^ain, there is no difference in character between the thick under- 

 ground rhizome of Yucca filamentosa (which never has an erect stem) 

 from the erect stems of its allies ( Y. aloifolia, Y. gloriosa, &c.) which 

 have no creeeping rhizomas. That the latter are but herbaceous 

 species that have learned to elevate their rhizomes while assuming 

 other characters, will be acknowledged by any reflective mind. That 

 this is true of other stoloniferous or rhizomatous plants horticulturists 

 have experience in the strawberry. Leaves, and an occasional root, 

 will sometimes appear from the apex of the common peduncle which 



