46 



Excerpt a Botanica. 



membranacea translucida cinctae (excepta specie unica, cui samara, 

 v. potius nucula, aptera, margine incrassata), plerumque squamis 

 strobilinis obtectae. 



Arbores v. frutices. Rami teretes v. obsolete angulati. Gemmae 

 perulatae. Folia serrata, v. crenata, v. nonnunquam (variatione) 

 pinnatifida, haud persistentia, petiolata (plerumque breve) : floralia 

 gemina v. subrosulata ; turionalia rloralibu? majora et saepe forma 

 aliena, haud raro angulata. Floratio vernalis, foliorum evolutione 

 coactanea. Amenta e gemmis perulatis orta : mascula jam exeunte 

 aestate praeterita evoluta, propter perulas fugaces mox nuda, sub an- 

 thesi pendula v. nutantia : squamis ciliolatis, plerumque basi et apice 

 plus miniisve acuminatis. Fceminea sub anthesi erecta v. resupinata. 

 Strobili erecti v. penduli, rachi gracili v. fere filiformi. Ramuli fruc- 

 tiferi maturatione peracta haud emortui. 



Sectio I. Pterocaryon, Spach. 

 Samarae ala, membranacea cinctae. 



* Strobili pedunculati, penduli ; squamis semper trilobis, tricarpis, sa- 

 maras late alatas per maturationem obtegentibus. 



B. ALBA*, Linn. — Trunco arboreo : epidermide nivea (rariiis fusca 

 aut aureo-fusca). Ramulis novellis resinoso-verruculosis, demum 

 ramisque saepius pendulis. Foliis biserratis, v. inaequaliter serratis, 

 v. grosse crenato-dentatis, cuspidato-acuminatis, v. acutis, punc- 

 tatis, basin versus integerrimis, oblique truncatis v. cuneatis, v. 

 rotundatis, v. cordatis ; turionalibus cordato-ovatis, angulatis ; no- 

 vellis viscosis ; adultis supra saturate, subtus pallide viridibus. 

 Strobilis cylindraceis, elongatis, crassis : squamarum lobis dissi- 

 milibus, saepe invicem incumbentibus : lateralibus suborbicularibus, 

 v. oblique ovatis, v. semi-orbicularibus, v. subcultratis, obtusis, 

 nunc terminali parallelis, nunc divaricatis, nunc deflexis ; lobo 

 terminali ovato, v. ovato-oblongo, v. oblongo, v. deltoideo, obtuso, 

 "v. acutiusculo, nunc abbreviato, nunc plus minusve elongate 

 Samara obcordato- v. obreniformi-biloba : alis loculamento (obovato 

 v. oblongo-obovato) longioribus ; duplo triplove (rarius parum) 

 latioribus. 



a. vulgaris. — Betula alba, auctor. plur. — Betula verrucosa, Ehrh. 



— Betula pendula, Hoffm. — Foliis floralibus rhomboideis, v. deltoi- 

 deis, v. ovatis, v. cordatis, acuminatis, longe petiolatis, ramulisque 

 annotinis glaberrimis. Pedunculis fructiferis petiolis plerumque 

 brevioribus. — Surculorum folia saepissime pubescentia v. hirta. 



(3. populifolia. — Betula populifolia, Willd. — Mich. fil. ! Arb. ii. 



p. 139, cum fig. (forma grandifolia). — Wats. Dendr. Brit. tab. 

 151 ! (forma foliis minoribus). — Betula acuminata, Ehrh. Beytr. 

 — Betula lenta, Duroi (non Linn.). — Betula cuspidata, Schrad. ! 

 ined. — Foliis longius cuspidato-acuminatis ; caeterum var. vulgari 

 omnino similis, simulque inter stirpes Europaeas passim occur- 

 rens. (V. v. c. et s. sp.) 



y. Dalecarlica. — Betula alba Dalecarlica, Linn. — Betula hy- 



brida, Blom. in Act. Holm. 1786, p. 168, tab. 6. fig. B. (non 



