BETULACEAE. — BETULA 463 



Ramuli floriferi fructiferique plus minusve abunde glanduliferi et 

 villosuli. Folia satis crassa, costa nervisque subtus valde promi- 

 nentibus satis sericea v. barbato-villosa, sacpisgime in axillis dis- 

 tincte barbata, sacpe ctiam facie pilosa; petioli plus minusve seri- 

 ceo-villosi. Amenta elliptica v. breviter cylindrica. . 8. B. uiilis, 



Ramuli floriferi fructiferique glabri, haud v. in var. septentrionali 

 distinctius glanduliferi. Folia tenuiora, lacviora, costa nervisque 

 subtus minus prominulis sparse sericea v. subglabra, interdum 

 tantum axillis barbulata; petioli glabri v. sparse sericei. Bracteae 

 sparsius v. vix margine glanduliferi et ciliati; amenta satis cylin- 

 drica 9. B. albo-sinensis, 



tt Samararum alae angustissimae, nucula 4-5-pIo angustiores v. amenta fructi- 



fera crasse ovato-elliptica 13^-2-plo longiora quam lata, pedunculo 



brevissimo crasso suffulta v. folia haud triangularia et basim versus 

 latissima. 



t Folia subtus discoloria, cinerascentia, obovata v. obovato-oblonga, 

 grosse aequaliter crenato-serrata. Amenta fructif era crasse cylindrica, 

 erecta (in speciminibus herbariorum quasi nutantia videntur) brac- 

 teae lobis angustis profunde trifidae. Subsect. c. Corylifoliae. 



11. B. coTylifolia, 



%X Folia subtus plus minusve viridescentes, baud obovata, margine dentibus 



minoribus angustroribusque serrata v. dentata. 



II Folia majora 6-14 cm. longa v. ovato-rotunda; petioli fere semper 



plus quam 1 cm. long! v. stiobili crassi subglobosi v. satis anguste 



cylindrici. Arbores altae. 



Amenta fructif era cylindrica, circiter 2-3 cm. longa et O.S cm. crassa, 



pedunculo satis tenui suffulta. Folia brevissime inaequaliter den- 



ticulata; petioli 8-10 cm. longi .... Subsect. b. Aspkhae. 



10. B. Schmidtiu 



Amenta fructifera crasse ovato-elliptica v. subglobosa, subsessilia v. 



pedunculo brevi crasso suffulta. Foliorum dentes distincti, plus 



minusve acuminati Subsect. d. Grossae. 



Samararum alae pleraeque distinctae, nucula 3^-% angustiores, 

 interdum basim nuculae versus valde reductae; strobili 

 elliptici, 1 }^-2-plo longiora quam lata v. lobus medius brac- 

 tearum lateralibus paulo longior. 



Folia satis anguste ovata in apicem longum caudatum producta, 

 nervis lateralibus approximatis ad costam inter se circ. 3-4.5 

 mm. distantibus, basi pleraque rotunda. Lobus medius brac- 

 tearum fere semper distincte elongatus; alae samararum 

 saepissime satis evolutae 12. B.^costata. 



Folia plus minusve ovata v. late ovata, brevius acuminata v. 

 haud caudata, nervis laterahbus ad costam inter se circiter 

 5-6 mm. distantibus. Bractearum lobi tres inter se sub- 

 aequilongae v. lobus medius paulo longzor; alae samararum 

 versus basim nuculae saepe valde angustatae (confer etiam 



14. B, Fargesii) 13. B. grossa, 



Samararum alae angustissimae; strobili subglobosi v. valde crassi 

 et magni, bractearum lobus medius valde elongatus. 



Folia late ovata v. ovato-rotunda, apice vix acuminata, basi 

 plus minusve late cuneata. Strobili subglobosi, ad 3 cm. 

 longi et 2.5 cm. crassi; bracteae utrinque glabrae, tantum laxe 

 ciliatae 16. B . glohispica. 



