BETULACEAE 





I Ua 



'tn is 



Juglans Butternut, Black Walnut 



i I. Juglana, walnut tree) 



PL 12, fig E : 1. 2 



1. Bark gray; twigs and foliage viscid hairy J.ch 

 _'. Bark 'lark brown; twigs and smooth f.ni 



rya Hickorj 



(Gr. carya, nut. walnut) 



1 Bark shaggy; leaves white-tufted at margin 



2, Mark not shaggj ; mature leaves almost smooth 



Betulaceae — Birch Family 

 mate simple leaves; il »wers monoecious, rarely dioecious, the stamin- 

 d often the pistillate also in catkins; staminite flower, sepals 2-4 or 0, petals 0, stamens 2-10; 

 pistillate flower sepals minute or 0, ovarj 1-2-celled, style 2-cleft; flower syncarpous, epigynous, 

 regular. 



I. Pistillate flowers clustered, not in a raceme or catkin ylus 



II. Pistillate flowers in a raceme or catkin 



1. Pistillate catkin small, terminal, few-flowered 



a. Fruiting bract leaf-like, 3-lobed ; bark smooth 



b. Fruiting bract closed, sac-like; bark rough 



2. Pistillate catkin compact, many-flowered 



a. Pistillate bracts 3-lobed, 3-flowered 



b. Pistillate bracts 5-lobed. 2-tlowered 



irylus — I lazd-nut 



(Gr. korys, helmet) 

 PI. 12, fig. D : 1, 2 



1. Twigs and petioles densely hairs ; involucre of nut short 



2. Twigs and petioles smooth; involucre with a beak 



t !axpinus — Hornbeam 



(Gr. karpinos, fruitful) 

 Small tree with smooth gray bark and very bard wood 



Ostrya -Ironwood 



(Gr ostrya, tree with very hard wood) 

 Small tree with furrowed bark and very hard wood 



Betula — Birch 



(L. betnla, birch-tree) 

 PI. 12. fig. C : 1, 2 

 1. Trees with white bark 



a. Leaves serrate or toothed, not deeply cut 



(1) Bark peeling in papery layers ; leaves ovate; native 



(2) Park pe July above, dark and furrowed at the base; 



leaves triangular 



b. Leaves deeply cut 

 (,1) Leaves with long slender points 



1 .eaves cut but not very long pointed 

 rees or shrubs with gray, yellow, or dark bark 



a. Trees 

 (1) Twigs fragrant: bark \ ed, yellowish gray 



2 Twigs not fragrant ; bark reddish brown ; trunk scaly 



b. Shrubs 



fall shrubs. 4-S m. high : leaves 

 Shrub 1-2 m. high ; leaves ovate to orbicular 



Alnus — Alder 



i L. alnus, alder) 



1. Leaves finely serrate, resinous beneath when young 



2. Leaves coarsely serrate, not resinous 



Carpinus 



Ostrya 



Betula 



. Units 



C. amcricdna 



C. rostrdta 



C. carolinidna 



0. virgini&na 



B. papyrifera 



B. verruedsa 



B. populifolia Iacinidta 

 i ucosa lobata 



B. lutea 

 B. nig 



B. Sandbcrgii 

 B. p&mila 



. I. alfit 



A. in< 



