ANTHOCEROTACEAE. 521 



Order 3. ANTHOCEROTALES. 



Gametophyte a prostrate dorsiventral thallus, varying from strap- 

 shaped to circular, with very little cell-differentiation, destitute of air- 

 spaces but sometimes developing intercellular spaces with mucilage; green 

 cells with one or a few large flat chloroplasts, often with a single pyrenoid. 

 Antheridia borne singly or in groups just below the upper surface of the 

 thallus. Archegonia in irregular dorsal groups, imbedded, the tip of the 

 neck alone projecting. Sporophyte differentiated into a broad foot and an 

 elongated cylindrical capsule, the latter growing indefinitely by means of 

 a basal embryonic region, splitting at maturity into two valves. Spores 

 surrounding a central sterile structure, the columella, and interspersed 

 with irregular, often multicellular elaters, with or without bands of thick- 

 ening. Four or five genera and about 150 species, widely distributed. 



Family 1. ANTHOCEROTACEAE Lindb. 



Anthoceros Family. 

 Characters of the order. 



1. ANTHOCEROS [Micheli] L. Sp. PI. 1139. 1753. 



Thallus suborbicular, variously lobed and often with plate-like outgrowths, 

 sometimes irregularly dissected, several cells thick and destitute of a distinct 

 midrib; green cells with a single chloroplast. Inflorescence usually (if not 

 always) monoecious. Capsule erect, much longer than the basal sheath, with 

 green cells in the wall and stomata in the epidermis. Spores variously rough- 

 ened; elaters without spiral bands of thickening^ composed of one to several 

 cells and sometimes branched. [Greek, flowering horn.] About 50 species, 

 largely tropical. Type species: A. punctatus L. 



1. Anthoceros laevis L. Sp. PI. 1139. 1753. 



Thallus nearly plane on the upper surface, dark green and somewhat lus- 

 trous, destitute of intercellular sjDaces. Capsule mostly 1-3 cm. long, the base 

 surrounded by a cylindrical sheath often flaring at the mouth; spores yellow, 

 the surface granular-papillose ; elaters yellowish, very variable in size and form, 

 often branched. 



Along the Adelaide Road, New Providence. Brace. Widely distributed in North 

 America, Europe and Asia. The Bahamian specimens are sterile and their deter- 

 mination is therefore doubtful. Yellow-spored Anthoceros. 



Phylum 4. THALLOPHYTA. 



This phyllum includes many thousand species of simple organi- 

 zation, grouped in many genera and families. The plants compos- 

 ing it have scarcely any woody tissue, and are propagated either bj' 

 spores or by vegetative division. Most of them are small, but there 

 are some large and conspicuous types in all the classes. 



34 



