1. Understanding Vegetative Morphology
Buds and Leaves
Understanding
Vegetative
Morphology

2. Buds Buds are short embryonic stems.
In angiosperms, buds are found at the nodes, in the leaf axil, or at the end of a stem.
Buds are especially useful for identifying twigs in winter condition.
Buds are protected by bud scales, a dense covering of hairs, and/or a sticky secretion.

3. Axillary Buds

4. Terminal Bud

5. Bud Types Accessory Bud Axillary Bud Flower Bud Leaf Bud Mixed Bud
Naked Bud
Pseudoterminal Bud
Superposed Bud
Terminal Bud

6. Generalized Angiosperm Stem

7. Lenticels and Leaf Scars
Lenticels are breathing pores in the young bark of a woody stem. Scattered lenticels dot the stem between leaf scars.
Leaf scars remain on a stem after the leaves have fallen. The circles within each scar are the severed ends of food and water-conducting bundles.

8. Lenticels

9. Leaf Duration
Leaves may function from a few days to many years, but most leaves function for only one or two growing seasons.
Deciduous leaves fall at the end of the growing season.
Evergreen plants are leafy throughout the year.
Marcescent leaves wither but do not fall during the winter or dry season.

10. Marcescent Leaves
Many oaks, beeches, and hornbeams are marcescent. This may be an adaptation to protect winter buds from browsing animals. The dried leaves remaining on the plant are not very tasty!

11. Leaf Arrangements

12. Generalized Angiosperm Leaf

13. Upper and lower leaf surfaces
Unifacial leaves lack any differentation between adaxial (upper) and abaxial (lower) leaf surfaces.
Bifacial leaves have definite differences between adaxial (upper) and abaxial (lower) leaf surfaces.

14. Bifacial Leaf Populus alba L.
Abaxial or lower surface
Adaxial or upper surface Abaxial or lower surface

15. Leaf Structure A leaf with a single blade is termed simple.
A leaf with two or more blades, or leaflets, is said to be compound.
The distinction between simple and compound leaves can be made by locating an axillary bud: an axillary bud is subtended by the entire leaf and never by individual leaflets.

16. Axillary Buds

17. Leaf Examples

18. Simple and Compound Leaves
Simple Leaves
a. Pinnate Venation
b. Palmate Venation
c. Parallel Venation
Compound Leaves
d. Pinnately Compound
e. Bi-pinnately Compound
f. Palmately compound

19. Compound Leaf Examples

20. Margin Patterns and Leaf Shapes

21. Leaf Shapes

22. Leaf Margins
As viewed from the side

23. Venation Types Primary vein (midvein)
The one most prominent vein in the leaf.
Secondary veins
Veins that branch from the primary vein.
Tertiary veins
Veins that link the secondaries.

24. Venation Patterns Percurrent or scalariform Ladderlike Reticulate
Netlike

25. Pinnate means ‘feather-like’
Pinnate Venation
Pinnate means ‘feather-like’

26. Palmate Venation
Arise from one point at the tip of the petiole, like fingers of an outstretched hand.

27. Leaf Apex Shapes

28. Leaf Base Shapes

30. Leaf Texture Membranous – very thin Chartaceous – papery in texture
Coriaceous – very thick

31. Surface Texture Terms Glabrous – lacking hairs.
Pubescent – with various hairs.
Glaucous – with a waxy covering.
Other Terms:
Arachnoid, canescent, hirsute, hispid, lanate, pilose, puberulent, scabrous, sericeous, strigose,tomentose,velutinous, villous.

32. Selected Features of Hairs

33. Liriodendron tulipifera L.
Simple leaf
Pinnate venation
Truncate apex
Cordate base
Long-petioled
Lobed

34. Lonicera sempervirens L.
Perfoliate upper leaves
Ovate to oblong
Glaucous beneath on abaxial surface
Simple leaves

35. Coleus x hybridus Voss. Simple leaf Margins serrate Acute apex
Obtuse base
Pinnate venation

36. Ricinus communis L. Simple leaf Palmately veined Peltate Long-petioled
5-11 lobed

37. Gymnocladus dioica Bi-pinnately compound leaf Leaflets entire
Pinnae in 3-7 pairs
Larger terminal ones with 3-7 pairs of ovate, acute leaflets to 3 inches long.

38. Amorpha L. Leaves odd-pinnate Many leaflets Leaflets entire
Compound leaves

39. Populus alba L. Simple leaf Long petioled Palmate venation Lobed
Rounded or slightly cordate
Truncate base

40. Taraxacum officinale Leaves simple
Leaves oblong, spatulate, or oblanceolate.
Nearly entire to sinuate-pinnatifid.
Terminal segment largest.

41. Pinus ponderosa Leaves linear Leaves needle shaped
Leaves usually in fascicles of 3.
5 to 11 inches long.

42. Cercis canadensis L. Leaves simple Leaves entire Palmately veined.
Leaves broadly ovate to nearly orbicular.
Cordate at base.
Attenuate at apex

43. Quercus macrocarpa Michx.
Leaves obovate
Leaves simple
Leaves pinnatifid with large terminal lobe.
Grayish-pubescent abaxial surface.
Deciduous