1. Vegetative Parts of Plants Spring 2010

2. Descriptive Terminology LEARN DESCRIPTIVE TERMINOLOGY = PHYTOGRAPHY - Vegetative - Floral/inflorescence - Fruit ASSOCIATE STRUCTURES WITH TERMS - Significant range of variation - Learn to identify major structures and modifications

3. R. W. Pohl Conservatory 5 th floor – Bessey Hall AVAILABLE TO BIOLOGY 366 STUDENTS - Free to look at plants to get a better idea of morphological structures. OPEN HOURS ARE 9:00 a.m. to 5:00 p.m. Monday - Friday - Some Friday afternoons conservatory is closed for pesticide applications. Some research areas are not available for general viewing PLANTS AND PLANT PARTS ARE NOT TO BE REMOVED - Pesticides have been applied to all plant material. - Do not eat any plant products.

4. Sequoia—tallest Sequoiadendron— most massive

5. Among the smallest plants in the world: Duckweeds (Lemna, Araceae) Root and 1-2 leaves; floating aquatic

6. Vegetative Parts of Plants NON-REPRODUCTIVE ORGANS: ROOTS - STEMS - LEAVES

7. Roots FUNCTIONS - Anchoring and support - Absorption of water and mineral nutrients; mycorrhizae STRUCTURE - xylem and phloem usually in a central vascular strand - no cuticle (except on aerial roots), root hairs. - branching pattern variable; adventitious roots - no nodes/internodes present in roots! DESCRIPTIVE TERMS: - Taproot (carrot) vs. fibrous roots (grass) - Fibrous, adventitious, aerial, fleshy, prop

8. Fibrous roots Tap root

9. Mycorrhizal associations were critical to the invasion of land by plants and are nearly universal in plants. endomycorrhizaeectomycorrhizae

10. Adventitious roots – roots produced by structures other than another root (e.g., stems)

11. Prop roots (adventitious) Pandanus (Pandanaceae)

12. Root Modifications: Ficus (Moraceae) “Strangler Fig” Adaptation for anchoring and nutrient gathering – begins as an epiphyte, and sends down adventitious roots.

13. Modifications of Roots: Mangroves – Anchoring, support, and aeration (coastline habitats)

14. Mangrove: Pre-dehiscence germination Root is already emerged from seed before it is separated from the tree.

15. Root Modifications: Aerenchyma in aquatics

16. Haustorial roots Found in parasitic plants. Dodder (Cuscuta, Convolvulaceae)

17. Stems FUNCTIONS FUNCTIONS - support and exposure of leaves to light, flowers to pollination agents, fruits to dispersal agents pollination agents, fruits to dispersal agents - vascular conduction of water/minerals and photosynthates - sometimes the primary photosynthetic organ STRUCTURE STRUCTURE - nodes and internodes; rearrangement of vascular tissues - ring of bundles or scattered bundles in primary stems - secondary growth produces secondary xylem (wood) - epidermis in primary stems; bark in woody plants - buds: terminal, axillary/lateral, bud scale scars DESCRIPTIVE TERMS: DESCRIPTIVE TERMS: - Branching patterns; bulbs, herbaceous, woody - Horizontal stems: above ground = stolons; below = rhizomes - Vines, shrubs, trees, succulent, tendril, phylloclade, etc.

18. Fig. 4.2 from the text

19. Stems: Nodes and Internodes

20. No apparent stems! Subterranean horizontal stems: Rhizomes

21. Rhizomes vs. roots

22. Stems: Some can be hollow; loss of pith during maturation

23. Modifications in the Petiolar Region Swollen nodes: Characteristic of the Pink Family, Caryophyllaceae

24. Woody Stems – Arborescent or shrubby habit

25. Stem Modifications: Bark (phellem) Most woody plants produce bark, a growth of the cork cambial layer, for mechanical protection and to reduce water loss.

26. Photosynthetic Stems phylloclades succulent stems

27. Basal rosette: In plants with a graminoid (grass- like) habit, stems may not be evident. This example is a ‘tussock’ habit, forming clumps.

28. Bulbs: stems (internodes) are shortened and leaves are fleshy and protective.

29. Leaves FUNCTIONS - light capture, production of photosynthate, transpiration STRUCTURE - petiole, stipules, pulvinus, blade (lamina), veins - vestiture (minimally a cuticle), hairs, scales, etc. - simple vs. compound (blade divided into discrete parts) - many modifications, including extreme reduction - virtually always with a bud or branch in the axil DESCRIPTIVE TERMS: - Many, based on leaf shape, size, color, venation, margin, apex, base, arrangement, number, presentation

30. Fig. 4.3 from the text

31. Modifications in the Petiolar Region Sheathing leaf bases

32. Modifications in the Petiolar Region Ocrea: stipular tube (characteristic of most of the Buckwheat Family, Polygonaceae)

33. Venation: Parallel vs. “Netted”

34. Unusual venation: Melastomataceae

35. Leaf blade: Pinnate Simple Compound Palmate

36. Fig. 4.5 from the text

37. Palmate Leaf – leaflets arise from one point

38. Fig. 4.4 from the text

39. Modifications for capturing insects Sarraceniaceae Droseraceae

40. Leaf Modifications: Kalanchoe (Crassulaceae) Adaptation for vegetative propagation – sheds pre- formed plantlets from leaf margins.

41. Fig. 4.15 from the text

42. Indumentum: Surface Structures Hairs, trichomes, scales

43. Variation in leaf shape morphology: Sassafras albidum (Lauraceae)

44. Armature: Thorns, spines, prickles

45. Summary Vegetative structures important in describing plants. Variations on similar basic morphology can be diagnostic for certain plant groups. An understanding of descriptive terms is essential for plant identification and to understand morphological evolution. Make lists of terms and their associated structures; drawings, however crude, may also help. Be sure to observe, compare and contrast related structures to avoid interpretation errors.