﻿Howe : New American Hepaticae 185 



black below and at margins > densely clothed at the sides with white 

 or tawny setae .3— .65 mm. long, those toward the apices often in 

 as many as 8—12 irregular series, mostly distinct at insertion, with 

 sharp, rigid, rarely slightly uncinate points, the terminal thallus- 

 lobes obcuneate or oblong-elliptical, obtuse or subacute, nar- 

 rowly and rather deeply unicanaliculate toward the apices or sub- 

 bicanaliculate, the furrow at the extremities commonly concealed 

 by the trichomes, the median sulcus sometimes nearly vanishing 

 toward the base, margins obtusely rounded, tumid, often connivent 

 on drying, the furrow then thatched by the somewhat forwardly 

 directed setse ; dorsal surface light green, minutely and regularly 

 reticulate ; ventral surface nearly plane and flat, with a few very 

 inconspicuous scales on either side of the median line at the apices, 

 falsely squamose in the basal parts through delamination due to 

 marcescence ; width of transverse sections 1.6—3 times their height, 

 the posterior subquadrangular with a light median sulcus, the 

 margins becoming more tumid and rounded in proceeding toward 

 the apex and the sulcus now and then double, the sections convex 

 ventrally only in the extreme apical region ; 20—28 cells in thick- 

 ness, texture nearly solid, the air-chambers narrow and vertical ; 

 epidermis primarily bistratose, the superficial layer at first papillate, 

 afterwards collapsed, and in the older parts reduced to a flattened 

 cellulose membrane incumbent on the lower layer : monoicous : an- 

 * theridia scattered, the ostioles elevated about . 1 mm. : sporogonia 

 numerous, in a single or double series, immersed, finally — espe- 

 cially when dry — hemispherical-protuberant above, together with 

 the long-unruptured covering, or subcorneal, the covering marked 

 with a dark-purple spot and bearing with rare exceptions 1-12 

 setae ; spores soon black and very opaque, narrowly or not at all 

 margined, 90-120/i in maximum diameter, minutely granulose- 

 papillate, with 9—12 areolae (visible only in the younger spores) 

 across the convex face, the walls of these with irregularly thickened 

 and salient angles, thus often giving this face in profile the appear- 

 ance of bearing columnar or wart-like elevations, areolae across 

 one of the plane faces 5—7 in number, scarcely elevated at the 

 angles. (Plate 337.) 



On rather dry and rocky soil. Calif or)iia : about San Fran- 

 cisco, "Mission Dolores," "Turk St./' "near Ocean House 

 (Dr. Bolander), Mission Dolores (Howe); Berkeley (Howe); Ukiah 



(Howe) ; San Mateo Co. (Prof. D. H. Campbell) ; Palo Alto (S. E. 

 Brown) ; Santa Ana Hills (Parish) ; Pasadena (McCIatchic). 



Kxsicc. Hep. Bor.-Am. 143* (as R. tumida Lindenb.). 



Hep. Am. 138 (as A\ arvensis Aust, var. hirta Aust). 



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