﻿of North America. 23 



Thallus rosettes mostly broad and flat, 10-20 mm. in diameter, 

 reticulate or nearly smooth, 4 or 5 cells thick in median parts, with 

 lacunae, but chiefly 3- or 2-stratose, subradiately cleft, the lobes com- 

 monly broad, rounded, denticulate or slightly crenulate-incised at 

 margin; surface-cells irregular and indistinct: involucres corni- 

 form, marginal or often becoming widely dorsal, horizontal or 

 ascending: capsules ovate- or oblong-cylindrical, 1.5-3 mm. long, 

 bivalved.the exterior cells thick-walled, those bordering the valves 

 yellowish-brown; columella early disintegrated; spores at first 

 yellow, becoming fuscous or nearly black at maturity, 36-48 ft in 

 maximum diameter, muriculate on the convex face. 



In an old ditch, Pointe a la Hache, Louisiana, (Rev. A. B. 



Langlois, no. 85). 



The thallus in the Louisiana plant is rather broader and less 

 incised than in a Cuban specimen collected by Wright and said to 

 have been determined by Gottsche, but the agreement in charac- 

 ters of capsule and spores is very close. It may be remarked 

 that the spores of N. orbicularis are sometimes obscurely tubercu- 

 late or papillate on the convex face, but this roughening in N. 

 Breutelii is much more pronounced. 



Explanation of Plates. 



Plate 321. Anthoceros Carolinianits occidentalis M. A. Howe. 

 I and 2. Portions of the thallus, natural size. 



3-5. Involucres, X I2 - 



6. Segment of thallus with marginal glandular-thickening, X 6. 



7. Transverse section of thallus segment (showing but one-half the width), X 2 3 



8. Spores, X 3°5- 



9. Pseudo-elaters, X 22 5 



All drawn from specimens collected in California; Figs. 1-3,8 and 9, Olema, 

 Marin Co. (Mr. W. L. Jepson) ; 4 and 6, Twin Oaks, San Diego Co. (Mr. F. W. 

 Koch); 5, Howell Mountain, Napa Co. (Prof. W. A. Setchell) ; 7, Mt. Tamalpais, 

 Marin Co. 



Plates 322 and 323. Anthoceros Pearsoni M. A. Howe. 



1. Segment of the thallus, with mature sporogonia, natural size. 



2, 3 and 4. Portions of a sterile thallus, showing its form, manner of branching 

 and the beginnings of the marginal glandular-thickenings, natural size. 



5. Marginal glandular- thickenings, fully developed, X I2 « 



6 and 7. Thallus segments with younger, sometimes peduncled, glandular- 

 thickenings, X I2 - 



8. Ventral view, showing glandular-thickening bearing root-hairs, X I2 - 



9 and 10. Longitudinal sections through well developed glandular-thickenings, 

 the latter exhibiting embedded antheridia, X 53- 



1 1. Transverse section of margin of the thallus, X S3* 



