.200 BOTANICAL GAZETTE. 



cate an established variety, or at least a well marked form. AVhetli- 

 er a good variety or not can better be told after the study of a 

 larger number of specimens and from other localities. There is at 

 least sufficient peculiarity to merit a careful description, and for the 

 present, the rank of variety may be assumed. 



Camptosokus rhizophyllus, Link, var. intermebius (n. v.). 

 Rootstalk short, ascending, clothed with a few dark-brown scales; 

 stipe green, Avith a brown base, containing a single rounded-trian- 

 gular fibro-vascular bundle without accompanying sclerenchyma; 

 fronds dimorphous, subcoriaceous, thinnish ; sterile frond 2 to 4 

 inches long, triangular-acuminate, sometimes prolonged and root- 

 ing; base broadly wedge-shape; apex blunt; fertile frond 4 to 12 

 inches long, narrowly lanceolate, broadest close to the base, greatly 

 attenuated and prolonged, rooting at the apex; base acute, broadly 

 wedge-shape, never cordate; veins strongly ascending, anastomos- 

 ing and forming about two series of areohe; sori few, oblong, 

 sometimes in pairs, or confluent at the upper part of the areolae; 

 indusium smooth, delicate, with a sinuous margin; spores ovoid, 

 with broad anastomosing wings of irregular width. Sterile blade 

 1 to tV inch broad near the base, fertile blade j to : i inch broad. 



Limestone cliffs in Eastern Iowa. 



The features which distinguish this from the typical form are 

 the single fibro-vascular bundle of the stipe without an anterior 

 nation of sclerenchyma, thinner and narrower fronds, simpler ve- 

 thread, acute base, shorter sori, and the greater differentiation of 

 sterile and fertile fronds. Of these characters the most pronounced 

 are the bundle of the stipe and the base of the blade. 



It is a significant fact that the deviations from the type are all 

 in the direction of the only other known species of the genus, C. 

 Sibiricus, a native of northeastern Asia. So considerable is the ap- 

 proach toward that species that if our plant had been found in 

 ompany with the foreign instead of the home sort, I doubt not it 

 ■would have been set down as a genuine variety of the former. I 

 Lave not, however, seen specimens of C. Sibiricus, and cannot 

 speak with perfect confidence, but form my judgment from the ex- 

 tended and verv complete description given in Milde's Filices En. 

 >i Atlan., and the figure in Hooker's 2nd Century of Fern*. Pro- 

 fessor Eaton writes me that a specimen in his herbarium corres- 

 ponds closely with Hooker's illustration except it is not so large. 

 The opinion of Linnaeus, that only one variable species of Campto- 

 sdrus exists, may again find favor. At any rate the form under 

 discussion is quite intermediate between the two established species. 

 '<)ne character, however, yet to be mentioned, marks the closer af- 

 finity with C. rhizophyllus. It is the widening of the blade above 

 the triangular base. By referring to the illustration, the slight 

 lobation of the blade at the widest part is evident in every frond. 

 These incipient lateral lobes are not auricles, but are of the nature of 



