THE STRUCTURE AND LIFE-HISTORY OF THE HAY-SCENTED FERN. 
By HENRY SHOEMAKER CONARD, 
Professor of Botany, Iowa College. 
HISTORICAL INTRODUCTION. 
The hay-scented fern, Dennstedtia punctilobula (Michx.) Moore (= 
Dicksonia punctilobula Willd.) first appeared in botanical literature in 1803, 
when it was described by Michaux as follows: 
[NMebhrodium] punctilobulum. N. majusculum: stipite nudo, ramis pinnulisque pu- 
bescentibus: fronde longa, bipinnata; pinnulis decurrentibus, subovali-oblongis, semi et 
ultra pinnatifidis; lobulis oblonguisculi, apice 2-4-dentatis, singulis unipunctiferis. Ods.- 
Habitus Polyp. filicis foeemina Linn. Haé.in Canada. [A. Michaux, 1803, p. 268.] 
There is nothing in the text to indicate that this is a new species. 
Michaux’s genus Nephrodium was extremely far-reaching, being defined 
in these words: ‘‘fructibus punctis subreniformibus’’ (p. 266). Among 
the species are WV. thelypteroides, marginale, filix-femina, and dryopteris/ 
Swartz (1806) placed the hay-scented fern in the genus Aspidium, in 
which he was followed by Willdenow (1810). The latter writer, both in 
his own text and in his quotation from Michaux, changes the spelling of 
the specific name to punctilobum. But he had already (1809) described it 
under the name of Dicksonia pilosiuscula, and this, too, is copied in the 
Species Plantarum. The text of the Enumeratio (1809) is as follows: 
DICKSONIA. 
Sort subrotundi distincti marginales. /zdustum duplex, alterum superficiarum exte- 
rius dehiscens, alterum e margine frondis inflexo interius dehiscens. 
‘1. DicKksonia pilostuscula. 
D. frondibus bipinnatis, pinnis pinnatifidis, laciniis dentatis, rachi pilosiuscula. 
Polypodium pilosiusculum. Miihlenberg in litt. Aadcfa¢ in Pennsylvania. (!) 
oD. 
An important addition to the other diagnosis is the notice of hairs upon 
the rachis. These are so characteristic as readily to distinguish this fern 
from any other in our native flora. In preparing the ‘‘Species’’, Willdenow 
recognized the similarity of his Aspidium punctilobum and Dicksonia pilosius- 
cula as expressed in the closing words of the description of the latter : 
An Aspidium punctilobum supra p. 270 dubie indicatum, eadem sit filix aliis ad 
dijudicandum relinquo? quum pinnule neque sint decurrentes neque pubescentes. 
5 
