Twig and Bud Characteristics by Jesse L. Saylor
001-003 Parts of Bud and Leaf Scar or Bundle Scar
001
a. Spines, thorns, and prickles: spines are modified short pointed twigs,
prickles are spine like outgrowths of epidermis, and thorns
are hard, sharp, leafless branches
b. Annual stem growth scars
c. Bud arrangement: alternate, opposite: useful to separate Buxus
from Ilex crenata, etc.
002 Leaf scars
a. Leaf scars raised: Acer palmatum (Japanese Maple),
Syringa reticulata (Japanese Tree Lilac)
b. Leaf scars round: Catalpa speciosa (Northern Catalpa),
Chionanthus virginicus (White Fringe Tree)
c. Stipule scars: Liriodendron tulipifera (Tulip Tree),
Magnolia (Magnolia). Chaenomeles speciosa has kidney shaped
stipules, but the stipule scars are not very visible.
d. With fuzzy patch or mustache above leaf scar: Juglans cinerea (Butternut)
003 Bundle scars (vascular traces from abscission layer formed where leaf fell off,
where xylem and phloem were connected)
a. Scattered: Liriodendron tulipifera (Tulip Tree)
b. In a ring: Catalpa speciosa (Northern Catalpa)
c. In a line: Aesculus hippocastanum (Common Horse Chestnut),
Frazinus (Ash)
d. In a horseshoe shape: Juglans cinerea (Butternut), Juglans nigra
(Black Walnut)
004 Pith (Pith is the central part of the twig, and is mainly a cylinder of parenchyma cells.
Pith is usually a different color from the xylem or wood surrounding it.)
a. Pith Continuous (various colors): Cotinus coggygria (Smoke Tree, orange),
Cotinus obovatus (American Smoke Tree, orange), Gymnocladus dioicus
(Kentucky Coffee Tree, salmon), Sambucus canadensis (American Black
Elderberry, white), Sambucus pubens (American Red Elderberry, brown)
b. Pith Chambered: Celtis occidentalis (Hackberry; pith is small and hard to see),
Eucommia ulmoides (Hardy Rubber Tree), Juglans nigra (Black Walnut)
c. Pith Diaphragmed: Liriodendron tulipifera (Tulip Tree),
Nyssa sylvatica (Sour Gum)
005 Terminal buds (some large and conspicuous; some colored): Aesculus (Buckeye),
Carya (Hickory), Fraxinus (Ash), Juglans (Walnut), Liquidambar (Sweet Gum),
Liriodendron (Tulip Tree), Magnolia (Magnolia)
006 No terminal bud (with a twig scar or twig that is spine like): Ailanthus altissima
(Tree of Heaven), Celtis (Hackberry), Koelruteria (Goldenrain Tree),
Phellodendron (Cork Tree), Rhamnus cathartica (Common Buckthorn),
Sorbaria (False Spiraea), Syringa (Lilac; two buds at end of stem, but not terminal),
Ulmus (Elm; bud at an angle, with a twig scar). Sometimes hard to tell because
some twig scars are not clearly visible.
007 Buds clustered at tips of stems: Quercus (Oak)
008 Flower Buds vs. vegetative buds: Cornus florida (Flowering Dogwood),
Cornus kousa (Kousa Dogwood), Cornus mas (Cornelian Cherry),
Corylopsis glabrescens (Fragrant Winter Hazel)
009 Bud covering
a. Buds resin coated: Abies concolor (White Fir; Abies concolor on top,
Abies nordmanniana below with no resin coating)
b. Buds sulfur yellow: Carya cordiformis (Bitternut Hickory)
c. Buds hairy: Pyrus calleryana (Callery Pear),
Sorbus aucuparia (European Mountain Ash), some Magnolia species.
d. Buds aromatic: Calycanthus floridus (Carolina Allspice),
Lindera benzoin (Spicebush), Myrica pensylvanica (Bayberry),
Sassafras albidum (Sassafras)
010 Buds buried or almost buried in the stem: Catalpa (Catalpa),
Gleditsia (Honey Locust), Gymnocladus dioicus (Kentucky Coffee Tree),
Philadelphus (Mock Orange), Sophora japonica (Japanese Pagoda Tree)
011 Buds stalked: Acer pensylvanicum (Striped Maple), Alnus (Alder),
Asimina triloba (Pawpaw, axillary buds), Parrotia persica (Persian Parrotia)
012 Buds subpetiolar (leaf stalk covers the bud; usually a leaf scar that almost
wraps around the bud): Cladrastis lutea (Yellowwood), Phellodendron amurense
(Amur Cork Tree), Platanus (Sycamore), Sophora japonica (Japanese Pagoda Tree)
013 Bud angle
a. Appressed or flat against stem: Celtis occidentalis (Hackberry)
b. Buds at angle: Ulmus americana (American Elm)
014 Bud scales
a. Bud scales cover bud: Syringa (Lilac)
b. Bud scales papery: Carya (Hickory)
c. Bud scale single cap like: Salix (Willow)
d. Bud scales imbricate: Amelanchier (Serviceberry), Fagus (beech),
Syringa (Lilac)
e. Bud scales valvate: Liriodendron tulipifera (Tulip Tree),
Viburnum lentago (Nannyberry)
f. Bud without scales (naked or foliose): Viburnum carlesii
(Koreanspice Viburnum), Viburnum lantana (Wayfaring Tree)
015 Spur Growth: Ginkgo biloba (Ginkgo), Malus (Crabapple), Nyssa sylvatica (Sour Gum)
016 Stems
a. Stems smooth (glabrous): Rhus glabra (Smooth Sumac), Viburnum opulus
(European Cranberry Bush)
b. Stems hairy: Rhus typhina (Staghorn Sumac)
c. Stems scurfy (with dry scales, rough to touch): Viburnum lantana (Wayfaring Tree)
d. Stems green (at least the last few years growth): Acer pensylvanicum
(Striped Maple), Kerria japonica (Japanese Kerria), Sassafras albidum
(Sassafras), Sophora japinica (Japanese Pagoda Tree)
e. Inner bark yellow or orange: Berberis (Barberry), Maclura pomifera (Osage Orange),
Mahonia aquifolium (Oregon Grape)
f. Stems hollow (at the nodes where leaves are attached, or at the internodes):
g. Lenticels (small, wart like structures scattered on the twig surface, used for air
exchange) present: Forsythia, Syringa patula
h. Stems with corky growth or wings: Euonymus alata
(Burning Bush; as brown lines and not wings on Euonymus alata cv. Compactus),
Fraxinus quadrangulata (Blue Ash), Liquidambar styraciflua
(Sweet Gum; not always present)
