﻿4 Howe: The Anthocerotaceae 



dinarily recognized, the second of which is not known to occur 

 within our limits. 



ANTHOCEROS L. Sp. PL 2: 1139- 1753- Ex Mich. Gen. PL 



10, pi. 7,/. 1,2. 1729. 



Thallus suborbicular, variously lobed or irregularly dissected, 

 now and then somewhat ribbon-shaped and subdichotomous, of 

 more than one layer of cells throughout, costa wanting, indistinct, 

 or rarely prominent; monoicous, proterandrous, or sometimes di- 

 oicous (?) * ; capsule erect, bivalved, much exceeding the involu- 

 cre in length, usually very long, withstomata(in the North Amer- 

 ican species). Spores granulose-papillate, tuberculate, or echinu- 

 late, rarely nearly smooth ; sterile cells (in all our species) without 

 spiral thickenings. 



Key to tlie Species. 



Spores yellow. 



Thallus with peduncled tubers from ventral surface. 



Thallus opaque; tubers few (1-3 to a segment), .25-1 mm. in diam., on 



peduncles .1-. 4 mm. thick. 



t 



Thallus pellucid; tubers numerous, .15-. 3 mm. in diam., on peduncles 

 .08-.09 mm. thick. 6. A. Domicilii. 



Thallus without ventral peduncled tubers. 



Capsule 3-6 mm. long; pseudo-elaters mostly of single cells, often as broad 



as long. 



4. A m hallii. 



Capsule 6-50 mm. long; pseudo-elaters mostly of 2-4 elongated (2-10:1) 



cells. 

 Spores with a few (8-15) crescentic verrucaeon convex (outer) surface, 

 or nearly smooth ; thallus usually with marginal, sometimes peduncled, 

 glandular-thickenings. 3. A. Pearsonu 



Spores thickly granulose-papillate. 



Involucres .8-2.5 mm. high, usually expanded at mouth; major 



segments of thallus 4-15 mm. long. I. A. laevis. 



Involucres 2-6.5 mm * high* scarcely or not at all expanded at 

 mouth ; major segments of thallus 8-30 mm. long. 



2. A. Carolinianus. 



# Certain species of Anthoceros have been described as dioicous, yet in a genus of 



* 



which the best known representatives are proterandrous, and in which the archegonia 

 are observed with so much difficulty, it may be suspected that careful investigation, 

 by modern methods, would show proterandry to obtain in all. 



\ Mature spores of A. phymatodes are unknown, but the close affinity of this 

 species with A. dichotomus of southern Europe makes it nearly certain that it be- 

 longs in the yellow-spored series. 



