THE FERN BULLETIN 



25 



Hairs of Dicksonia. — The boulder fern (Dicksonia 

 pilosiuscula) is frequently called hairy dicksonia, fine- 

 haired mountain fern and other names of similar im- 

 port to indicate its vestiture of hairs; indeed, the spe- 

 cific name here used also refers to the fact that the 

 fronds are hairy. Going further we find that these 

 hairs, or rather one of their qualities, is responsible for 

 several other common names of the plant for the ether- 

 ial oil which they secrete gives it the fragrance which 

 has caused it to be named hay-scented fern, sweet- 

 grass fern, sweet fern and the like. Microscopic ex- 

 amination of the leaf surface shows that the frond 

 bears two kinds of hairs, acicular and glandular. The 

 acicular hairs are simply pointed, but the glandular 

 ones are terminated by a bulb-like swelling from which 

 the fragrant and volatile oil is exhaled. The glandu- 

 lar hairs are most abundant on plants grown in dry 

 sunny places, following the rule for vegetation in gen- 

 eral in this respect. According to C. E. \Yaters the 

 oil distilled from this plant has a rather disagreeable 

 odor at close quarters, but diluted with ether and ex- 

 posed to the air reminds one of the usual fragrance of 

 the fern. 



The Ladder Ferx — According to a recent garden- 

 ing paper, our so-called Boston fern (Nephrolepis) is 

 often called ladder fern on the other side of the water. 

 With us it is frequently called the sword fern while the 

 Christmas fern (PolysticJuim acrostichoidcs) which is 

 constructed like the Xcphrolcpis but shorter, is 

 known to the trade as the dagger fern. De- 

 spite Shakespeare's query as to what's in a name 

 we are inclined to think that our British cousins have 

 the better of us as regards the cognomen of the spe- 

 cies in question. 



