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198 Cards in this Set

  • Front
  • Back
Climatic warming
-Due to the green house effect, may also create changes in natural ranges of trees
-Mankind has moved trees and plants over long distances by passing normal barriers to natural range, such as Oceans. mountains, and deserts
-When the exotic species are introduced to favorable habitats, they can become naturalized and develop at least as well as in their native area
Examples of exotic species
-Scratch Pine from Europe has become naturalized in Canada and the northeaster US
-Some species of eucaclyptus from Australia are now naturalized in California
-Mimosa and paulownia, natives to China, spread throughout much of southeastern US
-North American biotic communities have been structured by processes operative on both evolutionary and ecological timescales
Present forest regimes are responding to:
1. Changing climate
2. Geological processes
3.Fire regimes
4. The progressively increasing impacts of human populations and needs
When left unhamopered, trees and lesser vegetation tend to group themselves on
1. The basis of environmental factors
2. And their ability to compete with their associates into communitites
The flora of specific areas
The flora of specific areas and paticularly forest communities are often regarded and designated for practical reasons of description and study as distinct forest cover types or associations with one or a few dominant species
The Society if American Foresters has described 145 forest cover types in the US and Canada
-Each of these cover types occupies a particular geographic region and/or elevational zone
-Each is characterized by the species of trees, shrubs, and herbs that grow together
-Each may be permanent as a climax type or tasitory as a successional stage
Community boundaries are rather indistinct
-There is a broad transitional zone (ecotone) between two otherwise distinct forest types
The tow distinct forest types are
1. A continuum
2. Potential natural vegetation
A continuum
-An even more gradual change in communities
-It may be imossible to define
-Regardless of the community designations or delimitations, each species has a characteristic habitat or ecological range in terms of moisture, shade, and other environmental factors.
Potential naturl vegetation
-The descriptions of forest communities are in use today
-Kuchler described 116 plants communities in the US in terms of "potential natural vegetation"
-It means what would potentially exist without human influence
-Elevational zonation of forest communities may be particularly striking in mountainous areas.
Habitat Adaptations
1. Climate
2. Soils
3. Elevation
4. Aspect
5. Shade tolerance and intolerance
6. Werland to upland habitats
Hydrological Plant Indicator Continum
Obligate wetland plant (OBL)
-occurs in a wetland 99% of the time (Taxodium distichum)
Facultative Wetland plant (FACW)
-Occurs in wetland 67-99% of the time (Quercus laurifolia)
Facultative Plant (FAC)
-occurs in wetland 33-66% of the time (Carya illinoensis)
Facultative upland plant (FACU)
-Occurs in nonwetland 67-99% of the time
-But occasionaly found in wetlands (1-33%)
(Cercis canadensis)
Facultative Upland (UPL)
-Occurs in nonwetlands 99% of the time (Quercus virginiana)
-No above ground persistant woody tissue but may have underground prennating structures; may be annual, biennial, or perennial
-lower stems woody but upper stems herbaceous
-A woody low-saturate perennial plant with one to many slender trunks arising from near its base
-A large woody perennial plant with one to several relatively massive trunks and an elevated crown
-Possessing thick, usually soft, watery leaves and/or stem. Stem succulents and leaf succulents
-A woody or herbaceous plant with a long, slender, more or less flexible stem which cannot support itself
-A woody, climbing vine
(characteristics of the tropics)
Vegetative Morphology
-For tree identification, overal form or habit and vegetative parts are very important
-Including leaves, twigs, and bark
-Because they are more often present and accessible than reproductive parts
-Trees growing in the open tend to develop characteristic shapes that may be typical of species or genera
-Open-growing specimens have large crowns that may reach nearly to the ground, and the clear trunk is short, with considerable taper
Under forest composition, the form is very different:
-The bole is long
-More cylindrical
-Often clear of branches for one-half or more of its length
-Crown is small

However, most trees develop typical shapes only in the open
Due to variation in various habitats, habit is of limited use in identification
But, one can learn the shapes of the crown and pattern or branching of many species
Four primary habits are:
1. Excurrent
2. Deliquescent or decurrent
3. Palmlike
4. Yucca-type
-With a central dominant trunk and symmetrical, conical, or spirelike crown of many conifers and some hardwoods like
Deliquescent or decurrent
-With repeatedly forked stems giving rise to a spreading form such as in oak, males, and most hardwood trees
-With an unbranched trunk and leaves only in a top rosette, in palms and most cycads
-Either with a basal rosette of long stiff leaves and a central tall flowering stalk, or an irregularly branched thick trunks as in the treelike yuccas and cacti
Excurrent (conical) conifers and some hardwoods
-Pinus palustris
-Pinus taeda
-Pinus elliottii
-Pinus enchinata
-Taxodium distichum
-Juniperus virginiana
-Liriodendron tulipifera
Deliquescent (diffuse) and decurrent (forked stem)
-Quercus virginiana
-Quercus nigra
-Quercus falcata
-Ulmus americana
Palm like
-Sabal minor
Yucca (Basal Rosette)
Yucca sp.
-Lateral appendages on a stem
-Usually serves as the primary photosynthetic surface of the plant
-Can be extremely modified in morphology
Leaf persistence
-Bearing green foliage all year round
-The loss of leaves during unfavorable conditions (such as the end of each growing season)
Leaf Parts
-Leaf Blade
-Axialry bud
Leaf Blade
-Expanded portion of a leaf
-Stalk of a leaf
-The pair of appendages located at the base of a petiole
Axillary bud
-The presence of an axillary bud is very important to help identify where the leaf begins
-Look for it above the petiole
-Everything above the axillary bud is all one leaf
Leaf Compleaxity
-Simple leaf
-Compound leaf
Simple leaf
-A leaf with a single blade
-It is not divided into leaflets;there is always a flange of blade tissue connecting adjacent lobes
Compound leaf
-A leaf with more than one blade
-It is made up of two or more leaflets and these leaflets are wholly separate
-The stalk of a leaflet
-One of the segments of a compound leaf
-The axis of a pinnately compound leaf
Compound leaf
-Pinnately compound
-Bipinnately compound
-Tripinnately compound
-Palmately compound
- Trifoliolate
- Trifoliate
Pinnately compound
-A leaf in which there are more than three leaflets arranged in two rows along a common axis
-The leaflets are attached like the vanes of a feather
Pinna (plural Pinnae)
-The primary division (or leaflet) of a pinnately compound leaf
Bipinnately compound
-Leaf divided twice
Tripinnately compound
-Leaf divided three times; a pinnule is the ultimate division of a 2 or 3 times compound leaf
Palmately compound
-Where the leaflets arise from a common point of attachment; there is no rachis
-A compound leaf with 3 leaflets
-Three separate leaves arising from the same node
Leaf Attachment
-Having a petiole
-Lacking a petiole (or leaf stalk)
-A very short petiole
-Leaf base enwraps stem
Leaf arrangements
On normal twigs, leaves are usually arranged in one of three ways:
1. If they are paired at the same height, one on each side of the twig, they are opposite
2. When more than two are found at the same node, they are found at the same node, they are whorled, or verticillate
3. Where onle a single leaf is attached at each node, the leaves are alternate and also in a spiral up the twig
One other arrangement is subopposite
-Which is when the leaves appear nearly but not quite opposite
-This is characteristic of a few trees such as buckthorn, sweetleaf, and cascara
With the alternate arrangement, the determination of the number of leaves in each complete turn of the spiral is important
-Because it is often the same throughout a genus and sometimes applies to all the members of the same family
-Leaves attached to rhizome or underground stem
-Leaves attached to above ground stem
-One leaf per node
-2 Leaves per node
-3 or more leaves per node
Leaf Venations
-Consisting of a central midvein with many secondary veins emerging on both sides to form a feather-like pattern
-All primary veins arise at the same point at the base of the leaf
-Veins lie more or less parallel to the leaf margins
-It is somewhat intermediate between pinnate and palmate in which the lower most pairs of secondary veins, arising at or near the base of the midrib, is slightly larger than other secondaries and with larger tertiary veing going to the lower margins
-Has repeated forking or Y-branching, as found in ginko
-In the cycads and conifers, branch veins are rare; in hardwoods, there are smaller and smaller veins that form a netted pattern, which if often conspicuous and characteristic of genera and species
Leaf Shapes
- Acicular - Pinus ssp
- Lanceolate - Salix nigra
- Spatulate - Quercus nigra
-Reniform - Cercis canadensis
-Deltate - Populus deltoides
-Rhombic - Quercus laurifolia
-Linear - Quercus phellos
Leaf blade shaps
-Long and narrow with the sides parallel (>4:1)
Nearly recrangular with the sides parallel (2-4:1)
-Spearshaped; widening above base and then long tapering to apex (3-4:1)
-Eggshaped; broad nearest base (<3:1)
-Ovate, but with narrower end towards point of attachment
-Ellipse shaped; widest near middle and tapering at both ends
-Circle shaped
-Kidney shaped
-Needle like; very long and slender; variously shaped in cross section
-Delta-shaped; triangular
-Diamond-shaped; more or less symmetrical with the widest point at the center and the sides more or less straight to the apex and base
-Narrower than obovate shaped like a spatula with a broad apex and tapering to the base
Leaf Apices
(Leaf Apices)
-Sharp, ending in a point with straight sides to the apex (<90 degrees)
(Leaf Apices)
-Sharp, ending in a long-tapering point with concave sides
(Leaf Apices)
-Blunt, rounded (>90 degrees)
(Leaf Apices)
-A small, abrupt point
Leaf Bases
(Leaf Base)
-Sharp, <90 degrees
(Leaf Base)
-Sharp, long-tapering point
(Leaf Base)
-Blunt,>90 degrees
(Leaf Base)
-Heart shaped (equal rounded lobes at the base)
(Leaf Base)
-Unequal sized libes at base
(Leaf Base)
-Umbrella-like; the petiole is attached to the blade inside of the margin; often obicular in shape
Leaf Margins
-A margin without any toothing or division
-Scalloped or round-toothed
-A sav-toothed margin with sharp teeth pointing towards the apex
-Sharp teeth projecting at right angles from the margin
Leaf Lobing
-When the blde margins are indented one-quarter to one-half the distance to the midrib or base, it is considered a lobed leaf
-Lobed is used in a broad sense to include any degree of indentions, the base of the blade
Types of leaf lobes
-Pinnately Lobed
-Palmately Lobed
Pinnately Lobed
-Lobed towards the midrib but not reaching it
Palmately Lobed
-Lobes all arising from one point at the base of the leaf
-Indentions or incisions cut 1/4-1/2 distance to midrib or midvein
-Large, round-toothed, cut 1/8-1/4 distance to midvein
-Margins sharply and deeply cut,usually jaggedly
4 types of leaves in conifers
Acicular (needle)
-Which is long and slender
-Pinus, larix, cedrus
-Which is shorted than acicular, narrow, and either flat, triangular, or square in cross section
-Abies, picea, tsuga, sequoia, taxodium
Subulate (awl)
-Short, narrow, tapered to a sharp point, flat, and stiff
-Juvenile leaves of the Juniperus and other Cupressaceae
-Small, usually appressed and imbricated
-Thuja, Chamaecyparis, Cupresses, Calocedrus, Junipers
Decurrent leaf base
-In many of the conifers, the linear, subulate, and scale leaves are attached and extend down the stem for some distance below the point of divergence
-Its is called the decurrent leafe base
-The pegs of Picea and Tsuga and the leaves of Taxus have decurrent bases
Surface Features
-There are several features of the foliar micromorphology that are important in identification and classification of trees
-The surface of blades is usually not completely smooth if examined with high magnification
-The primary relief is generaly formed by the raised or sunken veins(a condition called rugase) or by the convexity of the epidermal walls
Surace Features 2
-Secondary relief(projections, striations, ridges) may be formed by epidermal cells or by a thick and sculptured cuticle on the epidermal cell walls
-Tertiary relief, on top of the cuticle, may be formed by a deposit of flaky, white epicuticular wax
-A smooth surface usually gives the balde a green, shiny appearance
Surface Features 3
-Added relief, cuticular or epicuticular, increases the relective surface, and the blade may have a pale color, often found on the lower surface
-Epicuticular wax forms a aple or white surface, again usually below, which is called glaucous
-Hairs (trichomes) on the leaf surface are of numerous types
-The relative density of hairs may be variable in relation o season or habitat
Leaf Surface features
Trichomes - hairs.
Cuticular-wax above.
Epicuticular-wax below.
Glabrous - smooth.
Pubescent - fine hairs.
Tomentose - wooly hairs.
Stomata and guard cells.
-Lacking (trichomes); a smooth surface
-Covered with hairs (also called trichomes)
-Hairs that branch at or near their base (star shaped from above)
-Hairs that bear glands (that break down into sticky beads of fluid); they may be stalked (stipitate) or sessile
-With a dense, soft coat of hairs that is hard to see through
-underside of mustang grape leaves
-A twig is the terminal or most recent growth of a branch, often delimited at the base by the terminal bud-scale scars (the position of last years bud, which developed into the twig)
Twig defenition is important
-Because twig characters and twig keys are based on just this part: the second year and older branches lose some of the twig features
-Twigs offer an excellent means of identifying trees and shrubs throughout the year, except for a short time during the spring when the buds formed the previous season are opening and those for the current season have not yet appeared
The most important features of twigs are:
Their buds, leaf scars, stipule scar, vascular bundle scars, and pith
Twig morphology
 Terminal bud.
 Pseudoterminal bud.
 Axillary or lateral bud.
 Collateral buds.
 Superposed bud.
 Bud scars.
 Leaf scars.
 Stipules.
 Stipule spines.
 Foliar spines.
 Prickle.
 Thorns.
 Pith (solid, diahram, chambered)
 These are conspicuous on most twigs
Lateral (axilary) bud
Those borne along the twig in the axils of the previous season’s leaves are termed lateral (axillary),
whereas the one at the apex is often larger and is called the terminal.
When true terminal bud is not formed
 In certain trees, a true terminal bud is not formed, and growth continues until checked by external
 When this occurs, the tender leading shoot dies back to the lateral bud below.
 This lateral bud then assumes the function of the terminal and is called pseudoterminal .
 It is distinguished from the true terminal by its smaller size and the presence of a minute twig
scar on the side opposite the leaf scar.
If more than one bud appears at a node,
 If more than one bud appears at a node, the bud directly above the leaf scar is considered to be the true
lateral bud and the others are designated as accessory buds.
 If the accessory buds are arranged on either side of a lateral bud,
 they are said to be collateral; if they appear above a lateral bud, they are called superposed.
 Buds are either scaly or naked.
Bud scales
Buds scales are actually modified leaves or stipules and serve to protect the enclosed embryonic axis and
its appendages
 In some buds, the scales are often rather numerous and overlap one another in a shinglelike fashion.
 Bud scales so arranged are imbricate.
Terminal bud durring spring
 When the terminal bud opens with the renewal of growth in the spring,
 the scales slough off, leaving terminal bud-scale scars.
 Naked buds lack scaly coverings and are common to certain trees of tropical climate but are relatively
rear elsewhere.
When two sizes of lateral bus occur on the same twig,
the larger usually contains the rudiments of flowers and are called flower buds.
Mixed buds
Mixed buds containing twig, embryonic leaves, and flowers are characteristic of some species, in
contrast to those enclosing twig and leaves only (leaf buds)
Epicormic buds
 Epicormic buds are either newly formed adventitious buds on roots or latent lateral buds of stems that
can give rise, upon cutting or damage of the main stem, to stump sprouts, coppice shoots, or “feathers"
along the bole.
 Coppice is a growth of trees from root or stump sprouts.
 leaf-bearing main axis of a plant
 aerial or subterranean
 divided into nodes and internodes
 gives rise to branches, leaves, and flowers
Stem features
-Axillary bud
-Bud scales
-Bud scale scars
-Leaf scar
-Stipule scars
 the position on a stem where a leaf or bud is or was attached
 the portion of a stem between two nodes
the upper angle between a leaf (or any other lateral structure) and the stem to which it is attached
Axillary Bud
 a bud borne in the axil of a leaf (also called a lateral bud)
 the structure giving rise to a leafy stem, a flower, or both; it may be naked or protected by bud scales or stipules; it may be lateral or terminal
Bud scales
 scale-like leaves that protect the buds
Bud scale scars
 scars remaining when the bud scales fall off
 mark on the stem where a bud scale was attached. When the terminal bud sprouts and its scales
fall off, growth rings are formed. The portion of a stem between two sets of growth rings
indicates one season's growth.
Leaf scar
 the scar left when a leaf falls from a twig; it contains one or more vascular bundle scars
Vascular bundle scars
 One the surface of each leaf scar are found one or more small dots or patches that show where the
strands of vascular tissue passed from the twig into the leaf.
 The size, number, and arrangement of these so called vascular bundle scars.
 usually a pair of appendages located at the base of a leaf but may be fused into a ring around the
stem; variable in size, shape and texture; serves for protection or to attract pollinators
Stipule Scars
 a pair of scars or a single ring-like scar when stipules fall away
 Stipule scars are not found on all twigs
 because many species are estipulate or the stipules are fused with leaf bases and the scars
disappear with the falling leaves.
 a "breathing pore" in the skin or bark of a stem.
 the spongey tissue in the center of a stem or twig.
 Pith can be solid, chambered, or diaphragmmed.
 Pith is readily discernible in cross and longitudinal sections of twigs.
The shape of the pith when viewed in cross section usually conforms to one of several patterns
 Ex) stellate (star-shaped) or pentagonal in oaks and cotton woods,
 Trigangular in alders
 Terete (round) in ash and elms and most others.
Pith varies in color
 Pith varies in color through shades of pink, yellow, brown, or green, to black or white.
 A longitudinal cut should be made through the center of the twig to determine composition.
 In most native trees, the pith is solid (or continuous) and homogeneous.
 A distinct modification of this solid type is the diaphragmed pith, which has more or less regularly
spaced disks of horizontally elongated cells with thickened wells.
 Ex) yellow-poplar and black tupelo
 the pith is divided into empty chambers by cross partitions and is termed chambered.
 Ex) walnut
 Chambering in certain species does not take place until the fall of the year, and the season’s growth is
homogeneous or diaphragmed until that time.
Continuous Pith
 A small portion at the end of each season’s growth apparently remains unchambered, and therefore the
age of a twig with this kind of pith may be estimated by sectioning it and counting the number of yearly “plugs” present.
Hollow Pith
 Hollow pith and spongy pith characterize some species of woody plants.
 The normal twig, with the leaves and buds spread apart by elongation of the internodes
 Is called a long shoot
 These may be entirely preformed within the bud or continue to develop during the season.
Short shoot
 If there is little growth and almost inconspicuous internode length
 The stem is called a short shoot or spur or dwarf shoot or branch.
 The stem axis and embryonic leaves are preformed in the bud.
There are two types of short shoots.
 Indeterminate
 determinate
 In which there is a functional terminal bud, and growth may continue for many year.
 In this type, the nodes are so close together that otherwise alternate leaves may appear whorled.
 In some cases, the “dwarfness” is released, and subsequent growth in following years may be a
normal long shoot.
 These are common found in apple, pear, birch, mountain ash, ginkgo, larch and deodar cedar.
 As the term implies, growth length is predetermined in the bud, there is no continued growth,
and the short shoot drops as a unit with its leaves.
 This type forms the pine fascicle, a short inconspicuous stem (with one to five needles), the
deciduous baldcypress twigs that drop in the fall, and the axis of cones and flowers.
Special feature
-Stipular spine
 an elongated, twining segment of a leaf, stem, or inflorescence by which a plant clings to its
 a woody, sharp-pointed, modified stem (has stem-like vasculature)
-Honeylocust, hawthorn, osage-orange
 a sharp-pointed modified leaf or leaf part (stipules)
Stipular Spine
 borne in pairs and lateral to leaf (or leaf scar)
 Are in the position of stipules
-Black locust
 a sharp pointed outgrowth from the epidermis
 Can occur at any location on the twig or leaf
-Rose, Aralia
Reproductive morphology
 Reproductive features offer the most stable characters
 Thus are the primary basis for classification of seed plants.
 In trees, they are often unavailable
 Because they are borne in the upper crown and last for a relatively short period of time.
Pollen grain
 The primary male reproductive structure is the pollen grain, which carries the sperm
 The corresponding female structure is the ovule, which contains the egg.
 Following the processes of pollination then fertilization, the ovule develop into the seed containing an
 There are various levels of sexual differentiation.
bisexual or perfect
 Some flowers contain both male and female structures and are called bisexual or perfect
 Found in dogwood, cherry, basswood, black locust, and others
 A plant with perfect flowers may be called synoecious or homoecious.
unisexual or imperfect
 If the cones or flowers have only one sex, they are unisexual or imperfect.
 If both male and female flowers or cones are on the same tree, then the tree is monoecious
 As in most conifers, oak, hickory, birch, etc.
 If the imperfect cones or flowers are one separate trees, then the tree is dioecious
 e.g., willow, poplar, holly, ginkgo, juniper, ash, boxelder, and a few others.
Many trees show developmental or ecological variation in the male/female expression
 A young maple may be male but then switch to female later
 An ash with male flowers one year have female flowers and fruits the next, then revert to male
again the following year.
Polygamous condition
There may also be a mixture of perfect and imperfect flowers in some trees which is a polygamous
 For instance, a buckeye inflorescence has a few perfect flowers plus many male flowers which
makes it polygamo-monoecious
Pollen and pollination
 Pollen grains are variable in size, weight, shape, number of pores through which the pollen tube may
emerge, and outer-wall sculpturing.
 Pollen type is characteristic of a family or genus and sometime species.
 Pollination is the transfer of pollen from the pollen sac to the ovule (in gymnosperms) and anther to
stigma (in angiosperms).
Among our temperate zone trees, there are three types of pollination mechanisms
 Wind (anemophily)
 Insect (entomophily)
 Bird (ornithophily)