, 
RicciA 38 
capsules is soon ruptured, exposing the spores. A. 2707177 is dioicous, 
the male plant (А. Watsoni Aust.) being smaller and more or less 
purple in color, the slenderly cylindrical ostioles elevated about .1 mm. 
КІССТА FLuITANS L. Sp. Pl. 1139. i753. 
Thallus thin, green, floating or immersed, often forming inter- 
tangled mats, destitute of rhizoids, or becoming terrestrial and attached 
by root- aie repeatedly dichotomous, the segments narrowly linear 
(.5-1.5 . wide, the entire thallus 1-5 cm. long), Ше median axis 
thickened, po most] flat margins only 2- or 3-stratose, air-chambers 
large, oblique, usually elongated, communicating with the dorsal sur- 
face by small pores surrounded by slightly modified epidermal cells : 
capsules ( found only in the terrestrial or semiterrestrial conditions) pro- 
tuberant below with the enclosing tissues of the thallus, the spores 
usually set free ventrally, these yellowish- brown, translucent, 79-75 и 
in maximum diameter, with a margin 3-6 p broad, the outer face with 
kao smooth meshes 12-15 » in width, inner faces less distinctly 
eolate. 
This species was collected by Messrs. Coville and Funston in Vegas 
Valley, Lincoln Co., Nevada (Death Valley Expedition, no. 400) and 
probably occurs within the limits of California. 
RICCIOCARPUS Corda ; Opiz, Beitr. 1: 651. 1829.* 
Plants lemna-like, floating or finally attached to the soil by the sub- 
sidence of the water, dark green, sometimes purple-margined, dichoto- 
mous, mostly 2-4-lobed, with a very pronounced median furrow, the 
lobes obcordate or obovate, the ventral surface bearing numerous long, 
pendant, linear or linear-lanceolate, reddish-violet, dentate scales; 
colorless ventral layer of thallus much reduced, the e chlorophyll- eee 
layer composed of large irregularly polyhedral с mbers separated by 
mostly unistratose lamellae ; epidermis with small ta distinct stomata. 
Dioicous. Antheridia in an elongated D like androecium situated 
in the median furrow. Capsule immerse 
The only recognized species is 
RicciocARPUS NATANS (L.) Corda, 2. с. 
din natans L. Syst. Nat. 1339. 1759 [Ed. то]. 
about т cm. long, the lobes 4-9 mm. wide: spores 45—55 р, 
MERE сые dark-brown at maturity, the areolae becoming obscure 
and the papillae more prominent. 
Rarely found with capsules. This species has not yet been collected, 
so far as is known, within the limits of the state, but it is found in Ore- 
gon and is likely to occur in California. 
*It would appear from a statement of M. Auguste LeJolis (Mém. Soc. nation. 
Sci. пас et math. Cherbourg, 29: 167. 1894) that a separate of Corda’s “Genera 
Hepaticarum " was published in 1828—in advance of its appearance in Opiz' Bei- 
tráge zur Naturgeschichte. 
