152 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



cylindrical to subcylindrical intergenicula to 2 mm. in diameter and 

 often longer than broad; branching non-percurrent, dichotomous, dis- 

 tichous, occasionally with a few pinnate branches below, sometimes with 

 secondary multifarious, proliferous branches arising from flattened faces 

 of intergenicula, these often reduced in diameter at the base, to less than 

 1 mm. ; intergenicula of branched upper parts usually shorter than broad. 

 Hat but thick (600-750 ju, in tetrasporic plants, thinner in antheridial 

 plants), 2.5-4.0 mm. wide, 2.0-2.5 mm. long, with well-defined, rounded 

 wings and thickened midrib area; genicula 250-280 /a long; intergeni- 

 cular medulla multizonal, composed of straight or nearly straight fila- 

 ments; tetrasporangial conceptacles irregularly placed on flattened faces 

 of intergenicula, tending to be on the wings, usually 2, sometimes 3-4, 

 700-900 p. in diameter; antheridial conceptacles in irregular aggrega- 

 tions of 3-7 (to 12) mostly in the middle area of flattened intergenicular 

 faces, 550-750 /a in diameter, more or less conical; cystocarpic con- 

 ceptacles irregularly placed, tending to be on the wings, 600-700 [x. in 

 diameter, 4-6, or up to 12. 



Type: Holotype is Taylor 34-643B, March 10, 1934, on sheet 98, 

 including slide 1417 and box 7012, in HAHF. 



Type locality: South Bay, Isla Cedros, Baja California, Mexico. 



Pacific coast distribution: California — Silva 2692, Jan., D. 

 5927, Dec, Willows Anchorage, Santa Cruz Island ; Silva 4205, Peli- 

 can Bay, Santa Cioiz Island, Jan. Pacific Baja Calif. — Silva 4813, Islas 

 Todos Santos, Feb.; D. 8528, Isla Guadalupe, Dec. (a narrow, thick, 

 little-branched, nearly wingless form); D, 9112a, 9116, Islas San 

 Benito, Apr.; D. 9863, South Bay, Isla Cedros, Apr.; D. 10596, Punta 

 Norte, Isla Cedros, Oct. 



Bossea angustata Taylor was based on a single specimen from Islas 

 San Benito. The specimen was part of an incidental collection obtained 

 June 4, 1933 by Mr. Fred Ziesenhenne on a brief Hancock Expedition 

 aimed at capturing elephant seals. The illustration of the type is some- 

 what enlarged (X 1.17). The type is provided with numerous long, 

 secondary proliferous branchlets which, in being much reduced in dia- 

 meter at their bases, give the specimen a peculiar appearance unlike 

 typical B. pachyclada. The primary stipe, however, is coarse and terete 

 as in B. pachyclada. Although several collections of Bossea have recently 

 been obtained from Islas San Benito, none correspond exactly with the 

 rather thin, proliferously branched B. angustata whose origin with 

 respect to depth is unknown. Portions of D. 9116, however, show the 

 same production of proliferous branches and of narrower, longer inter- 

 genicula, and suggest strongly that B. angustata represents only a 

 slender, thin, proliferous example of B. pachyclada. 



