﻿10 Howe: The Anthocerotaceae 



always be traced back to the margins of the frond. The glands or 

 tubers are 10-25 cells in thickness and consist of a more or less 

 distinctly defined capsule of 1-3 layers of undifferentiated cells en- 

 closing cells containing at first an unusually large chloroplast and 

 later filled with oil- drops or densely crowded with whitish gran- 

 ules. These organs are evidently food reservoirs, adapting the 

 thallus to persistence through the dry summers of the region that 

 the plant inhabits. In the neighborhood of San Francisco the 

 thickenings begin to appear in January or February, attaining full 

 development in May or June. In our no. 702, collected near 

 Mendocino, California, these marginal thickenings often enclose 

 numerous antheridia. 



We take pleasure in dedicating this clearly marked species to 

 Mr. W. H. Pearson, of Knutsford, Cheshire, England, whose 

 careful work on the Hepaticae of Canada and of various other 

 parts of the world is well known, and whose liberality in loaning 

 the Austin collection of Anthoceros has been an important and 

 much appreciated aid in the preparation of this paper. 



The above description of Anthoceros Pears oni is based upon 

 various specimens, but our no. 16, collected at Mill Valley, Marin 

 County, California, May 7, 1892, from which the figures of the 

 spores, pseudo-elaters and capsules have been drawn, we consider 

 the type of the species. 



4. Anthoceros Hallii Aust. Bull. Torr.Bot. Club, 6: 26. 1875. 



Anthoceros sulcatus Aust. /. c. 27. 



Thallus caespitose, erect, more rarely prostrate-entangled, 

 dark green or often extensively etiolated, sometimes indistinctly 

 plicate- costate ; the major segments attenuate at the base, flabelli- 

 form, or somewhat linear in the prostrate forms, 5-10 mm. long, 

 3-5 mm. broad above, sometimes once or twice subdichotomously 

 cleft, crenate-lobed or repand at apical margins, 6-8 cells thick 

 along the middle, otherwise 4-2-stratose, the lobes often terminat- 

 ing in irregular yellowish-brown or olive-green, glandular thicken- 

 ings, .3-2 mm. broad, these sometimes descending and tuber-like; 

 surface-cells quadrate-oblong to irregularly rhombic-pentagonal, 



colonies conspicuous, globose or fusi- 

 form : monoicous: antheridia usually in pairs: sporogonia very 

 numerous; involucres from just below the apex of the thallus, in 

 groups of 2-5 but distinct at base, obovate-quadrate to oblong-cyl- 

 indrical, 1-2.3 X o-7 2 m«n.| repand-dentale or sometimes irre^u- 



35-60 X 25-30 a ; Nostoc 



