BETULACEAE. — BETULA 463 



Ramuli floriferi fructiferique plus niinusve abundc glanthiliferi ct 

 villosuli. Folia satis crassa, costa nervisque subtus valrle proini- 

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

 tincte barbata, saepe etiam facie pilosa; petioli plus minusvc seri- 

 ceo-villosi. Amenta elliptica v. breviter cylindrica. . 8. B. ulilis. 

 Ramuli floriferi fructiferique glabri, baud v. in var. septenlrionali 

 distinctius glanduliferi. Folia tenuiora, laeviora, costa nervisque 

 subtus minus prominulis sparse sericea v. subglabra, intcrdum 

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

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



(li-ica 9. B. albo-sinensis. 



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

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

 brevissimo crasso sufTulta v. folia baud triangularia et basim versus 

 latissima. 

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

 grosse aequaliter crenato-serrata. Amenta fructifera crasse cylindrica, 

 erecta (in speciminibus herbariorum quasi nutantia videntur) brac- 

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



11. B. corylifolia. 



tX Folia subtus plus minusve viridescentes, baud obovata, margine dentibus 



minoribus angustioribusque serrata v. dentata. 



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



plus quam 1 cm. longi v. strobili crassi subglobosi v. satis anguste 



cylindrici. Arbores altae. 



Amenta fructifera cylindrica, circiter 2-3 cm. longa et 0.8 cm. crassa, 



pedunculo satis tenui suffulta. Folia brevissime inaequaliter den- 



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



10. B. Schmidiii. 



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



pedunculo brevi crasso suffulta. Foliorum dentes distincti, plus 



minusve acuminati Subsect. d. Ghossae. 



Samararum alae pleraeque distinctae, nucula }4-% angustiores, 

 interdum basim nuculae versus valde reductae; strobili 

 elliptici, l3''2-2-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. 

 baud caudata, nervis lateralibus ad costam inter se circiter 

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

 aequilongae v. lobus medius paulo longior; alae samararum 

 versus basim nuculae saepe valde angustatae (confer etiam 



U.B.Fargesii) 13. B.grossa. 



Samararum alae angustissimae; strobili subglobosi v. valde crassi 

 et magni, bracteanun lobus medius valde elongatu.s. 

 Folia late ovata v. ovato-rotunda, apicc vix acinninata, basi 

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

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

 ciliatae 16. .B. globispica. 



