Betulaceae (Birch Family)

     6 Genera (4 on campus)

     120 species
 
 

I.  Leaves

     A. Deciduous

     B. Alternate

     C. Simple

     D. Stipulate

     E. Double Serrate
 
 

II.  Flowers

     A. Monoecious

     B. Axillary staminate aments

     C. Axillary pistillate short spikelike aments
 
 

III. Fruits

     A. Small to medium size winged/unwinged nut

          subtended by papery or semiwoody bract
 
 

IV.  Economic importance

     A. Ornamental

     B. Veneer (doors, cabinets)

     C. Furniture lumber

     D. Fuel wood

     E. Edible Filbert/Hazelnut (Corylus)
 
 

V.  Range

     A. North temperate latitudesGeneric comparison/ Species characteristics
 
 

I. Betula (Birch)

     [Shining, in reference to bark]
 
 

     A. Very small laterally winged nuts subtended by

          three lobed bract in compact ament
 
 

     B. B. nigra (River birch)
 
 

          1. Deltoid leaves with white & pubescence underside

          2. Horzontally elongated lenticels

          3. Salmon-pink bark curls into horizontal sheets
 
 

II. Alnus (Alder) 

     [Latin name]
 
 

     A. Very small laterally winged nuts born on a woody

          persistent conelike ament
 
 

III. Carpinus (Hornbeam)

     [Latin name, Celtic for a yoke made from this wood]
 
 

     A. Small unwinged nuts subtended by three lobed bract

          in leafy spikelike clusters
 
 

     B. Carpinus caroliniana (American hornbeam, bluebeech,

          musclewood, water beech, ironwood)
 
 

          1. Elliptical leaves

          2. Pubescent, < 4mm long buds

          3. Smooth, blue-grey, fluted bark
 
 

IV.  Ostrya (Hophornbeam)

     [Greek = Shell, in reference to bladderlike bracts]
 
 

     A.  Small unwinged nuts enclosed in bladderlike bracts

          in elongated clusters resembling hops infructescence
 
 

     B. Ostrya virginiana (Hophornbeam, ironwood)
 
 

          1. Elliptical yellow-green leaves

          2. Brown, vertical platelike shredded bark
 
 

V.  Corylus (Hazel nut)

     [Latin name]
 
 

     A.  Large unwinged nuts subtended by foliaceous bract
 
 

     B. Corylus avellana (Filbert, Hazel nut)
 
 

          1. Oval to broadly elliptical leaves with capitate

               hairs

          2. Shrub
 
 
 

Salicaceae (Willow or Poplar Family)

     [Latin for willow]
 
 

     2 Genera

     350 species (2,3 on campus)
 
 

I. Leaves

     1. Deciduous

     2. Alternate

     3. Simple

     4. Stipulate

     5. Often with glands on petiole or lamina]
 
 

II. Flowers

     1. Dioecious

     2. Both male & female flowers born in aments
 
 

III. Fruits

     1. 1 celled, 2- to 4- valved capsule containing

          numerous tufted short lived moisture requiring

          seeds
 
 

IV.  Economic importance

     1. Coppice growth -> erosion control

     2. Fast growing, short lived ornamentals

     3. Wood pulp for paper

     4. Box, crate lumber
 
 

V.  Range

     1. Worldwide, but most abundant in cooler northern latitudes

        and mountainous regions of tropics

Generic comparison / Species Characteristics
 
 

Salix (Willow)

     [Latin for willow]
 
 

     A. Lanceolate to elliptical leaves, sessile or with short

          petiole
 
 

     B. Persistant stipules
 
 

     C. No terminal buds present because inflorescence in

          terminal position
 
 

     D. Lateral buds covered with single caplike scale
 
 

     E. V-shaped leaf scars
 
 

     F. S. nigra (Black willow) 

          1. Slender, brittle, purplish-green to orange-brown

               twigs

          2. Reddish brown lateral buds

          3. Brown to blackish bark subdivided into deep fissures

               seperating interlacing scaly ridges
 
 

     G. Common ornamental species

          1. S. discolor (Pussy willow)

          2. S. babylonica (Weeping willow)
 
 

Populus (Aspens, Cottonwoods, Poplars)

     [Latin for Poplar]
 
 

     A. Ovate to deltoid leaves with long terete or

          laterally compressed petioles
 
 

     B. Stipules not persistant
 
 

     C. Terminal buds present with imbricate scales
 
 

          1. Nonresinous in Aspens

          2. Resinous in Cottonwoods & Poplars
 
 

     D. Deltoid to Elliptical leaf scars
 
 

     E. Populus deltoides (Eastern cottonwood) 

          1. Deltate to ovate-deltate leaves with laterally

               compressed petioles and glands along margin

          2. Ashy gray bark subdivided into thick, broad, flattened

               or rounded ridges seperated by deep furrows
 
 

     F. Other common species important for pulp wood

          1. P. tremuloides (Quaking Aspen)

               a. Most widely distributed tree in USA

          2. P. grandidentata (Big Tooth Aspen)
 


 

Annonaceae (Custard-Apple Family)

     130 Genera
     2300 species

I. Leaves
     A. Simple
     B. Alternate
     C. Estipulate
     D. Entire
     E. Aromatic

II. Flowers
     A. Solitary
     B. Perfect
     C. Regular
     D. 6-9 tepals
     E. numerous stamens
     F. 3-celled pistil

IV. Fruit
     A. Berry with large seeds

V. Economic Importance

     A. Edible Fruit
          1. Custard Apple (Annona reticulata)
          2. Cherimoya (Annona cherimoya)
          3. Soursop (Annona muricata)
          4. Pawpaw (Asimina triloba)

VI. Range
     A. Tropics

VII. Asimina triloba (Pawpaw)
     [Native American name-G, three lobed-se]

     A. Small understory tree
     B. Obovate, foul smelling leaves
     C. Dark maroon flower
 

Aquifoliaceae (Holly Family)

     4 Genera
     420 species

I. Leaves
     A. Mostly evergreen
     B. Alternate
     C. Simple
     D. Stipulate

II. Flowers
     A. Imperfect (dioecious)
     B. 5-merous

III. Fruit
     A. Drupe

IV. Economic Importance
     A. Ornamentals
     B. Christmas decorations
     C. Furniture wood

V. Range
     A. Worldwide

VI. Ilex opaca (American Holly)
     [Ancient L name for oak-G, opaque-se]

     A. Spiny teeth (aculeate)
     B. Greenish-white flowers
     C. Poisonous red fruit
     D. Light gray, warty bark
 

Rhamnaceae (Buckthorn Family)

     53 Genera
     900 species

I. Leaves
     A. Simple
     B. Stipulate
     C. Alternate or subopposite

II. Flowers
     A. Perfect or imperfect (polygamous)
     B. 5-merous
     C. 2-, 3-celled pistil

III. Fruit
     A. Drupe, capsule

IV. Economic Importance
     A. Roots, bark, stems, leaves contain useful
          compounds for pharmaceuticals
     B. Edible jujube (Ziziphus jujuba) from Asia

V. Range
     A. Tropics & warmer latitudes

VI. Rhamnus cathartica (European Buckthorn)
     [Ancient Grk name for prickly shrubs-G,  purgative-se]

     A. Purplish black drupe
     B. Spine tipped branches