1919] Evans,— Notes on New England Hepaticae,—XV 155 
of the closely related N. obovata (Nees) Lindb., a species to be dis- 
cussed below. Schiffner! has pointed out the need of caution in 
employing differences of this type in separating the species of Nardia. 
In the writer's experience the cuticle of N. hyalina is sometimes 
smooth throughout but often shows minute verruculae, which are 
exceedingly delicate and inconspicuous. They are narrow and 
parallel in the basal part of the leaf but gradually become shorter 
toward the margin and show an oval or circular outline. The verru- 
culae are sometimes confined to certain leaves of a plant or to certain 
parts of a leaf; they are perhaps a little commoner in American 
material than in European. 
. Rhizoids are abundantly produced and often show a beautiful 
claret color, a feature which has been much emphasized in descriptions 
of the species. Since, however, the red color is not always present, 
and since the rhizoids of N. obovata and other allied species are some- 
times even more deeply pigmented, it is unwise to attach much im- 
portance to the color as a specific character. The rhizoids spring 
mostly from the ventral surface of the stem but occasionally from the 
leaf-cells near the ventral base or even from the cells of the bracts and 
perianth. This last condition is especially well seen in a deeply 
pigmented specimen from Naugatuck, Connecticut, where some of the 
old perianths are almost shaggy with rhizoids. In certain tropical 
species the rhizoids show a tendency to grow backwards and to form 
a compact bundle lying close to the stem, but this tendency is not 
apparent in N. hyalina, the rhizoids growing out irregularly in all 
directions. 
Underleaves are normally absent, as the descriptions indicate, but 
the ventral segments give rise to ephemeral appendicular organs which 
are homologous with underleaves. These were described and figured 
by Leitgeb ? many years ago. They are in the form of minute clusters 
of slime-papillae, four or five being usually present in each cluster, 
and it is easy to demonstrate them by dissecting off the apical portion 
of a stem and clearing it with potash solution. As Leitgeb pointed 
out, the papillae are really borne on the margin of a rudimentary scale 
consisting of only a few cells. 
Authors are now nearly unanimous in considering N. hyalina a 
dioicous species. At one time, however, certain hepaticologists 
1 esterr. Bot. Zeitschr. 50: 454 (footnote). 1910. 
2 Unters. über Leberm. 2: 8. pl. 9, f. 10. 1875. 
