RICCARDIA 71 
one portion remaining attached to the apex of each valve. Elaters 
unispiral, mostly somewhat attenuate at the ends, a few usually 
clinging to the “ elater-bearers"' and forming with them at the tip 
of each valve a pencil-like tuft. Inner layer of the capsule-wall 
with annular or spiral thickenings. Spores small. 
Key to the Species. 
Main axis of the thallus 3-6 mm. wide. 
Main axis or principal branches less than 2 mm. wide. 
Ramification pinnate. 
1) + 
I. №. pinguis. 
of branches one cell in width, obsolete in older parts. 
2. R. major. 
Unistratose margin of branches two or three cells in width. 
3. R. multifida ambrosioides- 
Ramification palmate. 
Thallus translucent when moist, surface cells 45-118 X 29-50 и, branches 
with unistratose margin one cell in width ; monoicous. 
4. R. latifrons. 
Thallus opaque, surface-cells 23-59 X 15-29 и, branches narrower, usually 
without trace of a unistratose margin, almost always gemmiferous at apex ; 
dioicous. 5. R. palmata. 
т. RiccARDIA pincuis (L.) S. F. Gray (as Riccardius), Nat. Arr. 
Bit. PL 1: 684: 1821. 
Jungermannia pinguis І. Sp. РІ. 1136. 1753. 
Aneura pinguis Dumort. Comm. Bot. 115. 1822. 
Thallus broad, thick, rigid on drying, dull green, with a some- 
what greasy lustre, simply pinnate or subpinnate, the main axis 
3-6 mm. wide, apices rounded : dioicous : androecia suborbicular, 
becoming short-oblong, .76-1.7 mm. x .85 mm., often geminate, 
Margin entire or crenulate ; antheridia 4—13, irregularly disposed : 
Ф branch with a laciniate margin, archegonia few ; calyptra 3.5-5 
mm. high, tuberculate or nearly smooth : capsule oval, brown ; 
elater-bearers conspicuous, 4- 14 the length of the valves ; elaters 
contorted, mostly 145-300 и X 9-12 #; spores brown, minutely 
рарШозе, 18-24 //. : d 
In mountain streams and very wet places. Hay Fork, Trinity 
Co. (no. 1119); Marin Co. (Underwood). 
The larger simpler forms of this species may, when sterile, be 
confused with certain sterile conditions of the genus Реа. Dis- 
tinguishing marks are, the pinnate, instead of dichotomous, branch- 
ing, apices rounded rather than emarginate, texture more rigid 
When dry, and a lustre as if saturated with some oleaginous € 
pound. The sporogonium has not been found in the Californian 
