78 Pleuroclada 



concavissimis (vix complicatis; perianthiis carnosissimis, in- 

 ferne 8 cellulas crassis; innovatione subflorali nulla. — Hab. 

 et Distr. Unica species nobis cognita ad saxa humectata 

 in montibus Europe et Groenlandise rarius occurit. 



Pleukoclada albescens (Hook). 

 Jungermania albescens Hook. Brit. Jung. t. 72 et suppl. t. 4 



Dioica depresso-ceespitosa stratificata albescens virescensve, sic- 

 cando cosrulescens. Caules pollicares raro longiores procumbentes in- 

 tricati, laxe subpinnati, interdum ex parte dichotomi, parce radieellosi, 

 eflagelliferi, validi, ovali-teretes, cellularum stratis 5 concentricis sub- 

 sequalium conflati, opaci; rami strict! subfastigiati. Folia subdissita 

 patula, insertione fere transversa, parum succuba orbiculata, conca- 

 vissima, fere bemispherica, adusque vel panlo ultra \ biloba, lobis ovato 

 triangularibus conniventibus acutis, sinu angusto acuto subobtusove ; 

 ceZii(Z« mediocres quadrato-bexagonse crasss, subleptodermes tamen, fere 

 planae, endocbromio parco subpellucidse. Folium axillare — e cujus gremio 

 ramus oritur — ex parte cauli, ex parte ramo adnatum, caeteris foliis 

 diversum, late ovatum, basi subcordatum, apice acutum nee bifidum. 

 Foliola subcontigua appressa subplana, foliis vix breviora, late ovata vel 

 ovato-lanceolata acuta vel subacuminata, raro obtusa, ntrinque suj)ra 

 basin valide unidentata, altero vel utroque dente interdum obsoleto. 



Flores dioici : Q in ramo brevi longioreve — pro pedicelli receptione ad 

 involucri basin usque excavato — terminales, innovatione propria nulla 

 suffulti, assurgentes, basi saepe valde radieellosi. Bractecs 8-jugae ap- 

 presso-convolutivae, extimse foliis submajores, intimse triplo fere majores, 

 basi liberse vel breviter connatse, oblongo-quadratse, ad \ bifidae, raro 

 trifidsB, segmentis subacuminatis acutis ; bracteola subminores apice in- 

 tegrse bifidulgeve, basi utrinque grosse 1 — 3-dentatae. Perianthia alte 

 emersa, foliis caulinis 7 plo longiora, clavata vel lineari-fusiformia, alte 

 trigona, ore constricto ssepe scarioso demum lacera erosaque, substantia 

 firma, basin versus 5 — 8 cellulas crassa, medio 2 — 4 cell., ad f alt. 2 

 cell., solum juxta apicem 1 cellulam solam crassa; cellula magnse elon- 

 gatae pellucidse. Calyptra pyriformis tenuis, basi sola 2 cell, crassa 

 ibidemque pistillidiis sterilibus sub 8 breviusculis lageniformibus obsita, 

 superne unistrata. Capsula perianthio 4 — 5 plo brevior alte exserta 



