150 THE AMERICAN BOTANIST 



and various other related species are not as evanescent as 

 these structures usually are. Almost as soon as produced they 

 are reported to devclc^p thick walls and remain on the plant 

 as long as does the epidermis from which they grow. It is 

 suggested that such thick-walled root-hairs are xerophytic 

 structures and indicate that the plants equipped with them are 

 adapted to life in dry regions. Whatever their cause they 

 evidently prevent the entrance of parasitic or symbiotic fungi 

 and so such trees have neither mycorhizas nor bacterial no- 

 dules such as most other Leguminosae possess. 



Maiden Hair Trek. — Permit me to offer a slight cor- 

 rection in an article in your last number (p. 23) concerning 

 Ginkgo. The union of sperm and egg takes place about Sept 

 1, at Tokio according to Hirase's original paper, and at the 

 same time at Philadelphia where I have followed the process. 

 At this time the seeds are still on the tree. Ikeno later showed 

 that this stage occurs on the tree, before the seeds fall. The 

 embryos mature about Nov. 1 at Tokio and at Philadelphia. 

 Hirase says that the seeds may or may not fall before this 

 time. At Philadelphia they iiad fallen. Does any body use 

 the name "maiden hair fern tree?" We are accustomed to 

 the n.ame "maiden hair tree." — Prof. Henry S. Conard, 

 Grinncll, lorca. ["Maiden hair tree" is probably more com- 

 monly used than "maiden hair Fcri) Tree." and yet it is ap- 

 parent that tlic latter is the proper name. TTiIs tree is so 

 nanud because it is like the maiden hair fern, not like a 

 maiden hair! The fern is so named because the black roots, 

 like hair, were supposed, according to the "dcKtrine of signa- 

 tures," to be good for falling hair and the plant was actually 

 used in "syrup of capillaire." Common names, however, are 



not based on logic or authoril\- ; they are the names commonly 

 used ; therefore this tree seems to be the Maiden hair 

 tree. — Ed.]. 



