Ebony Spleenwort 79 
wholly upon latter branch or extending along the veinlet of the 
latter (when one is present), next the midvein, opening toward 
the midvein: indusia whitish, delicately membranous, the mar- 
gin erose or slightly ciliate-erose. 
Spores brown, covered with anastomosing ridges. 
Habitat. Dry places exposed to the sun or partly shaded, 
usually near or on rocks. In old fields and pastures, among 
stones by the roadside, etc. 
Range. Florida to Maine and southeastern Ontario, west to 
Texas and Colorado. 
Asplenium platyneuron (Linneus) Oakes; D. C. Eaton, Ferns N. Am. 
I: 24. 1878. 
Acrostichum platyneuros. Linnzus, Sp. Pl. 1069. 1753- 
Asplenum ebeneum. Aiton, Hort. Kew. 3: 462. 1789. 
Tue blade of the leaf first produced by the young plant of 
Asplenium platyneuron is usually either obcordate, or bilobed 
with each of the two lobes slightly bilobed. If the first, it con- 
tains a once-forked vein; if the second, a twice-forked vein, each 
of the four veinlets occupying one of the lobes. Another very 
young leaf is trilobed. It contains a vein which is simple at 
apex, occupying the central lobe, and which bears two simple 
branches below, each occupying one of the lateral lobes. The 
leaf-blade becomes next somewhat more complexly lobed and 
its midvein develops farther. Pinne are then gradually formed, 
in the same manner as in A. trichomanes.** In A. trichomanes, 
however, the pinne are often opposite, whereas in A. platyneuron 
they are nearly always alternate. 
The leaf’s petiole is green at first but soon begins to change 
color, although not, at least noticeably, as soon as in A. tricho- 
* See page 65. 
