﻿166 DICOTYL. SEU EXOGEN/E. betdla. 



p, commutata, trunco elato, foliis duplicato-dentatis. j ln America bo- 



reali, Sumars Prairie (Lyall), Popsfield, Massachusetts (Asa Gray), Ore- 



gon (Lyall), Kgl. 1. c. p. 401. t. 7. flg. 6-10. B. papyracea et papyrifera 



auct ex parte. Subspeciei subsequenti proxima et solummodo strobili 



lobis lateralibus rectangulis v. recurvatis diversa. 



Subspeeies VI, pnpyrifcra, arborea, ramulis fructiferis glabris v. plus minus 



glanduliferis v. junioribus laxe pilosulis, foliis ramulorum fertilium e basi 



rotundata v. rarius cordata ovato-oblongis v. subovatis v. rarius subcordatis 



acuminatis duplicato-dentatis subtus in venarum axillis saepissime barbatis, 



samaraealis nuoula duplo triplove latioribus, strobili squamarum lobis late- 



ralibus erectis. — In America boreali et rarissime in Sibiria orientali. Rgl. 



Bem. ilber Bet. in Bull. d. Mosc. 18. p- 401. Ab affinibus subspeciebus ante- 



cedentibus 4 et 5 squamarum lobis lateralibus erectis facile dignoscitur. — 



Arbor excelsa v. humilis. Kamuli steriles turionum plus minus glanduliferi, 



initio pilosuli v. rarius dense pubescentes. Folia subtus ad nervos pilosa, 



turionvun pilosula v. rarius dense pubescentia. Strobili cylindriei, elongati, 



saepissime apice attenuati, erecti v. insigniter penduli; squamae pilosulae v. 



ciliatae. Variat : 



a, communis, ramulis fructiferis glabris v. laxe glanduliferis, foliis ramu- 

 lorum fertilium e basi rotundata ovato-oblongis. $ ln America boreali, 

 New-York, Massacbusetts, a Nova Anglia ad Pensylvaniamet Wisconsin, 

 et in hortis europasis culta. Rgi. 1. c. p. 401. B. papyrifera Mich. fl. bor. 

 am. 2. p. 180. B. papyracea Willd. spec. pl. 4. p. 464. Ait. hort. Kaw. 

 ed. 2. v. 5. p. 300; Mich. hist. d. arbr. Betula p. 133. t. 1; Wats. 

 dendr. brit. 2. t. 152; Willd. Berl. Baumz. p. 58; Pursh fl. am. sept. 2. 

 p. 621; Hook. fl. bor. am. 1, p. 155; Torr. New-York 2. p. 199; Asa 

 Gray Mamiel of bot. p. 459. B. nigra Duh. ed. nov. 2. t. 51. B. excelsa 

 Duh. 1. c. t. 52. B. grandis Schrad. in ind. sem. h. Gbtt. 1833. p. 2 et in 

 herb. B. alba var. papyrifera Spach 1. c. p. 188; Endl. 1. c. p. 19 ; Regel 

 monogr. p. 23. Artor excelsa, cortice albo insigniter papyraceo. Ramuli 

 et folia initio saepissime laxe pilosula v. turionum folia densius pubes- 

 centia, tandem glabrescentia et subtus tantum ad nervos plus minusve 

 pilosa in axillisquo venarum barbata. Folia turionum sterilium qvata v. 

 cordata, initio laxe pilosula deinde glabrescentia v. rarius pubescentia. 

 Squamarum strobili lobus intermedius lateralibus angustior. 



(3, cordifolia, ramulis glabris v. sparse glanduliferis junioribus laxe pilo- 

 ' sulis mox glabris, foliis ramulorum fertilium e basi cordata v. dilaiato- 

 rotundata cordato-ovatis. — In Terra nova (de la Pylaie in hb. DC.), el 

 in America boreali, Maine (h'b. Asa Gray), Lake superior, Pic River 

 (Loring, in hb. Asa Gray). Rgl. 1. c. p. 401. B. cordifolia Regel, mo- 

 nogr. p. 28. t. 12. ng- 29-36. Arbor verosimiliter mediocris. Ramuli 

 fusci , rigidi. Folia acuminata v. rarius acuta, subtus ad nervos pilosa et 

 in venarum axillis plus minusve barbata. Strobili erecti v. penduli, elon- 

 gato-cylindracei v. rarius breviores; squamarum lobi ciliolati subaequilati, 

 lobus mtermedius laterales superans. 

 Y, humilis, trunoo humili suffrutesoente, foliis ramulorum fertilium ovato- 

 subrotundis acutis, squamarum strobili lobis porrectis v. rectangulis. 

 5 In America boreali-occidentali, Saskatchawan (Bourgeau), Rocky 

 inountains (Parry, E. Hall et P. Harbour), White mountains Tuckerm,). 

 B. papyracea var. minor Tuck. teste AsaGray. Bamuli conferti, flexuosi, 

 glanduliferi v. juniores pubescentes, dein glabrati. Folia ovato-subrotunda, 

 acuta, parfa, 1 j poll. longa, simpliciter v. duplicato-dentata, juniora 

 petiolique ssape pubescentia, dein.glabra v. subtus ad nervos tantum 

 pilosula. Samararum alae nucula usque triplo latiores. 



Subspecies VII, pulieseens, ramulis plantarum juniorum sterilium turionum- 

 que dense pubescentibus, ramulis fertilibus initio puberulis deinde saepissime 

 glabrescentibus, , foliis acutis (nec acuminatis) , samarae alis nucula sesqui- 

 duplo latioribus. — In Europa et Asia media et boreali, in America bo- 

 reali. Rgl. Bem. uber Bet. in Bull. de Mosc. 18. p. 402. B. pubescens Ehrh. 

 Beitr. p. 98; Willd. spec. pl. vol. 4. p. 462; Mossl. Handb. 2. Aufl. 4. 



