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Leaf Arrangement
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Alphabetical w/ Definitions
  1. Abaxial
    The side pointing away from the axis, usually the underside of a leaf, stem or branch.

  2. Abscission
    The loss of a structure, such as a leaf, due to a chemical process where cells form a callous layer blocking food and water causing the structure to fall off.

  3. Accessory Bud
    Buds that are not found in the axils of the leaves but are often found above or adjacent to axillary buds at a node.

  4. Acerose
    Narrow elongated leaf; Needle-shaped.

  5. Acuminate
    Sides curving concavely upward and inward then tapering to a fine point on the leaf apex.

  6. Acute
    An angle that is less than 90º with straight lines and having a point on a leaf apex.

  7. Adaxial
    The side toward the axis, usually the upper surface of a leaf, stem or branch.

  8. Alternate
    Leaves or stems situated one at a node. Leaves can alternate in a distichous pattern 180º apart along two sides of the stem, or at lesser angles around a stem.

  9. Anther
    A section of the male part of a flower containing the pollen.

  10. Apetalous
    Lacking petals.

  11. Apex
    The top; the terminal portion of a leaf; plural is apices.

  12. Apiculate
    A leaf or petal having a short slender point that is flexible.

  13. Appressed
    Firmly against another object, as a bud to a stem.

  14. Arching
    Branches of shrub (or any part of plant) that curves outward from the main body of the shrub.

  15. Asymmetric
    A plant part that has an irregular shape. (See also Oblique).

  16. Attenuate
    Leaf tissue tapers down the petiole (toward the base) to a narrow base always having some fleshy leaf on either side of the petiole.

  17. Auriculate
    Ear-lobed shaped leaf base(s) attached to petiole.

  18. Awl-shaped
    Tapering to slender stiff point; Short stiff margins narrowing to a point, often sharp and found on young Junipers.

  19. Axil
    The angled point on a stem where the leaf (or petiole) attaches to the stem.

  20. -B- Back to Top
  21. Basal
    Beginning from the lower extremity of a plant part, as in leaves from the base of a stem.

  22. Base
    The bottom; the proximal (nearest the stem) portion of a leaf (See also Apex).

  23. Bipinnate
    Referring to a compound leaf where the pinnate leaflet has subdivided into smaller leaflets giving a more feather-like appearance.

  24. Blade
    In trees, shrubs, vines and grasses, blade refers to the individual leaf; often referred to as Lamina.

  25. Bloom
    White or waxy coating on the surface; also referred to as being glaucous.

  26. Bract
    A modified leaf that is frequently showy and thought of as part of a flower; appears below actual flowers.

  27. Branch
    A secondary stem that forks off of the main stem or trunk.

  28. Branchlet
    A diminutive version of a branch; a small branch-like twig.

  29. Broad-oval
    An ellipse that is less than twice as long as it is wide; Used often for habit and leaf but can be used for other descriptions.

  30. Broad-pyramidal
    Pyramid shaped or triangular with a wider base than pyramidal.

  31. Broad-rounded
    Nearly circular, but wider than tall.

  32. Bud
    The unexpanded next season’s growth of leaves and flowers; undeveloped leaves and shoots.

  33. Bud Scale
    One of the sheaths that cover a bud; There can be a few to very many;

  34. Bulbous
    A tree bud that is rounded or ‘bulb-like’.

  35. Bullate
    A raised blistered appearance between veins. Tissue near veins appears to pucker.

  36. Bundle Scar
    Refers to the vascular bundles that are found in the scar left behind on a stem after a leaf falls off (abscises).

  37. -C-  Back to Top
  38. Calyx
    Outer part of the flower usually green and consists of the sepals; Plural calyces; (See also Corolla).

  39. Cambium
    A meristematic layer of cells responsible for the growth of the bark and the wood.

  40. Capsule
    Dry dehiscent fruit that has more than one carpel or ovule.

  41. Carpel
    The female reproductive organ that consists of the stigma, style, and ovary.

  42. Catkin
    A unisexual spike flower that is a long unbranched petal-free male or female flower with bracts between the flowers and that uses wind to spread the pollen; hangs down and can be ornamental.

  43. Ciliate
    Fringe of fine hairs; can be found on leaves, stems, buds, flowers, etc.

  44. Collateral
    Situated side-by-side; often in reference to multiple buds at a node.

  45. Columnar
    Shaped like a column; much longer than wide and having a defined central leader.

  46. Compound
    Divisions where there are two or more similar characteristics.

  47. Concave
    Curved inward

  48. Cone
    Woody cluster of seeds on a scale attached to a center axis; see also Strobile.

  49. Conical
    Cone-shaped being taller than wide and attached at the wide end.

  50. Connate
    The fusion of plant organs; such as sexual organs, leaves, petals, etc.

  51. Connate-perfoliate
    Fusion of the bases of a pair of opposite leaves that attach directly to the stem (no petiole).

  52. Contorted
    Twisted or bent in many directions; can appear on any part of plant.

  53. Convex
    Curved outward.

  54. Cordate
    Heart-shaped; can be overall leaf shape, or leaf base with the notched section connecting to the petiole.

  55. Coriaceous
    Thick leathery texture of a leaf that is pliable.

  56. Corolla
    The collective name for all of the petals of a flower; portions of the petals can be fused into a corolla tube (See also Calyx).

  57. Corymb
    A flat-topped or round-topped indeterminate inflorescence with the lower pedicels growing to the same height as the upper and flowering first from the outside towards the center (See also Cyme and Umbel).

  58. Crenate
    Rounded teeth along margin.

  59. Cuneate
    Narrow wedge-shaped leaf base tapering to a point at the petiole.

  60. Cuspidate
    Tipped with a short, abrupt point on a leaf apex narrowing to tip.

  61. Cyme
    Flat-topped or round-topped determinate inflorescence; paniculate; terminal flower blooms first (See also Corymb and Umbel).

  62. -D-  Back to Top
  63. Deciduous
    A non-evergreen plant that loses it leaves after its growing season.

  64. Decumbent
    A plant structure that grows along the ground with the tip curving upward (See also Prostrate).

  65. Decurrent
    A leaf blade that attaches to and runs down the stem to the connecting point.

  66. Decussate
    Leaves arranged in opposite pairs, rotating 90º at every node (See also Distichous).

  67. Dehiscent
    An organ splitting open when ripe; commonly used for seed pods and anthers (for pollen release).

  68. Deltoid
    Triangular like the Greek letter Delta, bottom two corners can be angular or rounded.

  69. Dentate
    Square or rectangular teeth along margin pointing outward (See also Serrate and Crenate).

  70. Denticulate
    Diminutive of dentate with very small square or rectangular teeth.

  71. Determinate
    Predefined end of growth; in flowers the terminal flower blooms first stopping the elongation of the main axis.

  72. Dialated
    Expanded or flaring open.

  73. Dichotomous
    Veins extend from a common point forming a “y” pattern and fanning out as each vein branches into two.

  74. Dioecious
    Plants that have all male or all female flowers but not both; often referred to as having “two houses”. Dioecious plants are thus either male or female.

  75. Dissected
    A part of a plant that is deeply divided into narrow segments (See also Incised).

  76. Distichous
    Leaves are arranged in two ranks along either side of a stem (See also Decussate).

  77. Divergent
    Splitting or spreading apart.

  78. Divided
    Split, cut, or lobed all the way to the base or midrib.

  79. Doubly-Serrate
    Forward pointing teeth with each tooth (serration) having smaller serrations on it.

  80. Downy
    Covered by a mass of small fine hairs that are soft.

  81. -E-  Back to Top
  82. Elliptical
    Narrow oval broadest in middle, narrow at the two ends; ellipse-shaped.

  83. Emarginate
    The apex of the leaf is notched towards the petiole at the midvein.

  84. Entire
    Continuous smooth margin, not toothed, notched, or divided.

  85. Epidermis
    The outer layer of a non-woody plant (for a woody plant see bark).

  86. Even-pinnate
    Pinnately compound leaf with a pair of terminal leaflets instead of one terminal leaflet resulting in an even number of leaflets. (See also Pinnate).

  87. Exfoliate
    To peel or pull away from; such as bark on a tree.

  88. -F-  Back to Top
  89. Falcate
    Hooked like a sickle or beak of a falcon.

  90. Fascicle
    A bundle or enclosure surrounding multiple parts (some evergreen needles, e.g. pines, are in a fascicle).

  91. Fasciculate
    Multiple leaves appearing bundled in a fascicle (such as on a pine).

  92. Fastigiate
    Branches erect and grown parallel, giving a broom-like appearance.

  93. Fetid
    Foul-smelling, rancid.

  94. Fibrous Roots
    Roots that are well branched, more thread-like, and scattered with no central leader (See also Taproot).

  95. Filament
    The stalk of the stamen that holds the anther on a male flower.

  96. Flabellate
    Fan-like, fan-shaped.

  97. Flower
    Reproductive part of plant consisting of one or more of the following: stamens, pistils, sepals or petals.

  98. Foliage
    All of the leaves of a plant.

  99. Foliose
    Leaf or leaf-like; small unfurled leaves without a bud scale.

  100. Fringed
    Decorative or stringy hairs along margin; can be seed, buds, leaves, etc (See also Tufted).

  101. Funnelform
    Funnel shaped; increasing in size from the base to the apex.

  102. -G-  Back to Top
  103. Glabrous
    Hairless surface.

  104. Gland
    An organ, projection, or tissue that sometimes performs special functions, like secretion of oils or sticky subtances.

  105. Glaucous
    White or waxy coating on the surface often referred to as a bloom.

  106. Globose
    Round or spherical in shape.

  107. -H-  Back to Top
  108. Habit
    The overall appearance or shape of a plant crown; a plant in silhouette.

  109. Habitat
    The environment where a plant grows.

  110. Heartwood
    The innermost part of a branch or trunk; usually darker in color than the sapwood.

  111. Hip
    The term used for the berry-like fruit of a rose plant i.e. Rose hip; is actually a fleshy structure surrounding achenes.

  112. Hispid
    Rough surface with stiff and bristly hairs.

  113. Hoary
    Densely covered with short gray or white hair.

  114. Hypanthium
    Cup-shaped structure formed from the fusion of the basil portions of the petal, sepals, and anthers; Usually surrounds the pistils. Commonly found in the Rosaceae family.

  115. -I-  Back to Top
  116. Imbricate
    Overlapping structures like shingles on a roof; e.g. scales on an imbricate bud.

  117. Impressed Venation
    Veins sunken or below the surface of a leaf.

  118. Incised
    Cut sharply, deeply, and irregularly into angular serrations along the leaf margin.

  119. Indehiscent
    An organ, e.g. a fruit, that does not split open at maturity (See also Dehiscent).

  120. Internode
    Part of the stem between two growing points or nodes.

  121. Involucre
    Multiple bracts beneath a flower sometimes holding on into the fruiting stage as in acorn caps on oaks (Quercus).

  122. Involute
    Margins rolled towards the top of the leaf.

  123. -K-  Back to Top
  124. Keeled
    A ridge running down the center of the bud scale; ridged like the keel of a boat.

  125. -L-  Back to Top
  126. Lamina
    The expanded portion of a leaf or petal; Refers to individual leaves (See also Blades).

  127. Lanceolate
    Longer than wide with widest point below the middle tapering to both the apex and base. Narrower than ovate.

  128. Leaf Scar
    Scar left behind on a stem after a leaf falls off (See also Abscission).

  129. Leaf Sheath
    A covering or small stipule that covers part of a leaf.

  130. Lenticel
    A small corky protrusion that allows for gaseous exchange between the air and the plant tissues.

  131. Linear
    Long and thin like a line with parallel sides; length is more than 4 times the width (See also Oblong).

  132. Lobed
    Rounded division or segment of a leaf or other organ. Can be symmetrical or asymmetrical and vary in sizes depending on species. Lobes are cut less than half way to the base or midvein.

  133. Lobulate
    Small rounded lobes around leaf edges (See also Lobed).

  134. Low Spreading
    A broad plant habit that hugs the ground (See also Prostrate).

  135. Lustrous
    Shiny or glossy.

  136. -M-  Back to Top
  137. Malodorous
    Bad smelling.

  138. Meristem
    A group of cells responsible for rapid cell growth and differentiation in specialized tissues.

  139. Midvein
    The primary vein found in many leaves; Often it runs down the center of leaves.

  140. Monoecious
    Both male and female flowers found separate on the same plant; flowers imperfect, both staminate and pistillate flowers borne on the same plant (See also Dioecious).

  141. Mucronate
    Leaf apex tipped with short abrupt point on midvein.

  142. Multiple Fruit
    A fruit formed from several flowers.

  143. -N-  Back to Top
  144. Naked Bud
    A bud lacking scales.

  145. Narrow-pyramidal
    Tetrahedral; triangle that is taller than wide. Width is about half of height. Same as reticulate.

  146. Net-veined
    Veins interlaced as in a network across the face of a leaf.

  147. Node
    Point where new leaves or branches emerge (See also Internode).

  148. -O-  Back to Top
  149. Obcordate
    Inversely cordate; heart shaped; if it is a leaf apex, the petiole attaches at the narrow end.

  150. Oblanceolate
    Inversely lanceolate; Much longer than wide with the widest point above the middle. Narrower than obovate (See also Lanceolate).

  151. Oblique
    Unequal or asymmetric especially in leaf-blade or leaf base.

  152. Oblong
    Two to four times longer than wide with nearly parallel sides.

  153. Obovate
    Inversely ovate or teardrop-shaped; leaf connected to petiole at narrow end. Wider than oblanceolate (See also Ovate).

  154. Obtuse
    Rounded leaf apex, greater than 90º at apex.

  155. Odd-pinnate
    A pinnately compound leaf that ends in a single leaflet so that there is an odd number of leaflets (See also Even-pinnate and Pinnate).

  156. Opposite
    Appear across from one another at the same node; opposite leaves may also appear decussate (each pair alternating at 90º angles at every node).

  157. Orbicular
    Circular or rounded in leaf.

  158. Oval
    Two times longer than wide with rounded ends.

  159. Ovary
    The lower portion of the female pistil that contains the ovules (See also Stygma and Style).

  160. Ovate
    Teardrop-shaped in outline and attached (to petiole) at the broad end; Wider than Lanceolate.

  161. Ovoid
    A three dimensional part that appears egg-shaped; buds, fruits, etc.

  162. -P-  Back to Top
  163. Palmate
    Lobed, veined, or divided from a common point; usually 3 or more parts radiating from a common point; Veins, leaflets, lobes, etc.

  164. Panicle
    A twice-branched, inflorescence maturing from the bottom towards the top.

  165. Parallel
    Veins running nearly parallel; can be veins running parallel to the leaf axis or to each other.

  166. Pedicel
    A stalk of an individual flower (See also Peduncle).

  167. Peduncle
    A main stalk of an inflorescence from which the individual pedicels may arise. (See also Pedicel).

  168. Pendulous
    Drooping or hanging downward.

  169. Perfect
    A flower that has both pistils and stamens.

  170. Perfoliate
    Leaf surrounds stem directly attaching to it; stem appears to go through the center of leaf; there is no petiole.

  171. Petiole
    The leaf-stalk or axis connecting the leaf to the stem.

  172. Petiolule
    The stalk or axis of the leaflets in a compound leaf .

  173. Pinnate
    Parts arranged along opposite sides of an axis; A leaf with a prominent midvein and veins along both sides of the midvein; Compound leaf with leaflets arranged along opposite sides of a petiolule or leaf stalk.

  174. Pistil
    The female part of the flower typically consisting of a stigma, style, and ovary. Commonly referred to as the gynoecium (See also Stamen).

  175. Pith
    The spongy tissue in the center of a stem or root (consisting of parenchyma cells).

  176. Polygamo-dioecious
    Mostly dioecious, but with some perfect flowers. (See also dioecious).

  177. Polygamo-monoecious
    Mostly monoecious, but will some perfect flowers (See also dioecious).

  178. Polymorphic
    Many shaped.

  179. Prickle
    A small sharp growth arising from the epidermis (See also thorn).

  180. Procumbent
    Growing or following along the ground, but not rooting where it touches.

  181. Prostrate
    Lying flat along the ground.

  182. Puberulent
    Diminutive of pubescent; having fine short hairs.

  183. Pubescent
    The surface of leaf or stem is covered with short fine hairs.

  184. Pyramidal
    Triangular-shaped that is taller than wide with the width being 2/3 the height.

  185. -R-  Back to Top
  186. Raceme
    A once-branched inflorescence that flowers from the bottom up (See also Panicle).

  187. Rachis
    The main axis of a compound leaf or inflorescence.

  188. Radial
    Parts arranged around a common center point.

  189. Recurved
    Bent or curved backward.

  190. Reflexed
    Bent abruptly backwards or downwards.

  191. Resinous
    Having or containing resin; being sticky.

  192. Reticulate
    Appearing like a net, or network (See also Net-veined).

  193. Revolute
    Margins rolled downward towards underside of leaf.

  194. Rhombic
    Diamond-shaped with 4 sides; petiole attached at one of the corners.

  195. Rhizome
    An underground stem, distinguishable by the presence of nodes, buds, or leaves (See also Stolon and Tiller).

  196. Rosette
    Radiating cluster of leaves.

  197. Rounded
    Wide curved shape that is wider than Obtuse with less of a point, while not being so flattened as to approach Truncate.

  198. Rugose
    A wrinkled surface as on a leaf.

  199. -S-  Back to Top
  200. Sapwood
    The outer and lighter wood that is actively transporting water.

  201. Scabrous
    Rough texture due to short stiff hairs or the epidermal cells.

  202. Scale
    A small dry bract acting as a covering or layer.

  203. Scale-like
    Having small overlapping layers.

  204. Schizocarp
    A dry dehiscent fruit that breaks apart into two halves.

  205. Scurfy
    Covered with small bran-like scales.

  206. Serrate
    Sharp forward-pointing teeth along leaf margin.

  207. Serrulate
    Many minute sharp forward-pointing teeth along leaf margin.

  208. Sessile
    Attached directly without a stalk; a leaf or flower directly attached to a stem.

  209. Shoot
    A young green stem.

  210. Shrub
    A small woody plant with multiple stems from the ground and that is not usually climbable; all of the branches are produced from or near the base.

  211. Simple
    A single undivided leaf. A simple leaf may have lobes, or serrations (See also Compound).

  212. Sinuate
    Strongly wavy margins only in one plane; close to being lobulate (See also Undulate).

  213. Sinus
    On a lobed leaf a sinus is the valley between the lobes; they can vary greatly in size and shape.

  214. Spatulate
    Spoon or spatula-shaped, with a rounded leaf blade that tapers to the base.

  215. Spinose
    Bearing spines along leaf margins, Tiny spines at nodes on stems.

  216. Spike
    An inflorescence that is unbranched with sessile flowers maturing from the bottom up.

  217. Spine
    A hard sharp woody growth that emerges from below the epidermis and is either a modified leaf or stipule (See also Thorn).

  218. Spinose
    Having spines; having sharp woody growths.

  219. Spirally Arranged
    The actual pattern of alternate leaves on a stem;

  220. Spur
    A short shoot with leaves or fruit. Ex. Ginkgo; A hollow projection from a flower either in the sepals or petals.

  221. Stalk
    A supporting structure for a leaf, flower, or fruit.

  222. Stamen
    The male part of a flower typically consisting of an anther and filament; Commonly referred to as the androecium. (See also Pistil)

  223. Stem
    Supportive structure for buds, leaves, and nodes; can be single or branched; sometimes found underground.

  224. Sterile
    Barren or infertile; not able to produce seed.

  225. Stigma
    The recepticle for pollen on the pistil.

  226. Stipule
    A bract or appendage at the base of a petiole (usually found in pairs).

  227. Stolon
    A horizontal stem that roots at the nodes and tip and can produce a new plant (See also Rhizome and Tiller).

  228. Strobile
    A cone or an inflorescence resembling a cone. Ex. Alders

  229. Style
    The tube that connects the stigma and ovary of the pistil (the female part of the flower).

  230. Subopposite
    Leaves appear near opposite but slightly skewed at a node without a fascicle (See also Opposite and Alternate).

  231. Superposed
    Appearing one right above another; an accessory bud found above the true bud.

  232. Symmetric
    A balanced appearance; Having the same number of floral parts in any angle.

  233. -T-  Back to Top
  234. Taproot
    A central root that has smaller fibers coming off of it (See also Fibrous root).

  235. Tendril
    A twining stem that supports a vine.

  236. Terminal
    The end or tip of a part (See also Basal).

  237. Thorn
    A hard sharp modified stem; can branch and have leaves and buds (See also Spine and Bristle).

  238. Tiller
    A stiff basal or underground shoot that is mostly erect (See also Rhizome and Stolon).

  239. Tomentose
    Covered in a mat of short soft hair

  240. Trace
    The scar of the veins left behind when the leaf falls off (abscision), located within a leaf scar.

  241. Tree
    A large woody plant typically with a main trunk.

  242. Truncate
    Leaf base or apex is perpendicular to leaf petiole and relatively straight across

  243. Trunk
    The main stem of a tree.

  244. Tufted
    A clump of hairs that are arranged in a dense cluster (See also Fringed).

  245. Twig
    A branch or shoot from a shrub or tree.

  246. Twining
    A stem that spirals around another object for support.

  247. Two-ranked
    Aligned in two rows on opposite sides.

  248. Two-scaled
    Two scales on a bud.

  249. -U-  Back to Top
  250. Umbel
    A flat-topped inflorescence with the pedicels (flower stalks) arising from one point (See also Corymb and Cyme).

  251. Undulate
    A leaf margin that has upward and downward waves in it giving the leaf a more three-dimensional appearance (See also Sinuate).

  252. -V-  Back to Top
  253. Vase-shaped
    The habit of a shrub or tree which begins narrow and widens out the higher you go.

  254. Valvate
    Two organs meeting without overlapping as in many leaf buds.

  255. Variegated
    Striped, mottled, or bordered color on a what normally would have been solid.

  256. Vascular bundle scar
    The scar left where the vessels were found within the leaf scar; Similar to Trace.

  257. Venation
    The pattern of the veins in a leaf.

  258. Vine
    A climbing or trailing plant that is not supported by the stem but by some other sort of fastening (i.e. tendrils).

  259. Volute
    Rolled up (See also Involute and Revolute).

  260. -W-  Back to Top
  261. Warty
    A bumpy, rough surface texture.

  262. Weeping
    Hanging down or pendulous.

  263. Whorled
    Three or more leaves arising at a node.

Tutorial Terms

Leaf Arrangement

Leaf Bases

Leaf Apices

Leaf Shapes

Leaf Margins


(See definitions to the left)

  • Accessory
  • Appressed
  • Conical
  • Imbricate
  • Pubescent
  • Single-scaled
  • Spur
  • Stalked
  • Terminal
  • Two-scaled
  • Valvate





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