MUSCALES.] 



ANDR^ACEyE. 



63 



Order XIX. ANDR^ACEiE.— Splitmosses. 



Andraeacese, Nixiis PL 24. (1833) ; Endl. Gen. xxii. 

 Diagnosis. — Spore-cases opening by valves, with an operculum, without elaters. 

 Branching moss-like reddish or brown plants, with nnbricated ribbed or ribless leaves. 



Spore-case with a calyptra, seated 

 on a fleshy apophysis, splitting longi- 

 tudinally into four equal valves whose 

 summits are always bound together 

 by the persistent operculum. Peri- 

 stome 0. Spores surrounding a cen- 

 tral columella. 



Linnaeus considered the only genus 

 of which this order consists, the same 

 as Jungermannia ; more recent ob- 

 servers have withdraAvn it to asso- 

 ciate with Urnmosses. It hardly, 

 however, belongs more to the one 

 than the other ; if it agrees with 

 Urnmosses in having an operculum, 

 it disagrees in haAing a valvular 

 spore-case ; and if it accords with 

 the Scalemosses in the latter circum- 

 stance, it differs from them in the 

 former, and in the want of elaters. 



Natives of cold and temperate 

 regions, especially on rocks in bleak 

 places, as liigh as the limits of eter- 

 nal snow, where they form a close 

 mat. 



Their uses are unknown. 



Andraea, Ehr. Acroschisma, Hook, f I. 

 Petrophila, Brid. 



Numbers. Gen. 2. Sp. 13. 



Position. — Jungermanniacese. — 

 Andr £ACE^. — Brvacese . 



Fig. XLIV. 



Fig. XLIV.— 1. Andraea nivalis, natural size ; 2. the same much magnified ; 3. spore-case with the torn 

 calyptra ; 4. spore-case after the discharge of the spores ; 5. columella with a few spores adhering ; 6. 

 Andraea nipestris much magnified ; 7. its antheridia and thread-like paraphyses.— //oo/:er. 



