1. Anatomy Review BIO 201 - Botany

2. Herbaceous stems Have separate vascular bundles In each bundle: - Xylem toward center - Phloem toward outside Bundle arrangement important - monocots randomly scattered - dicots in ring

3. Corn stem – a monocot

4. Corn with detail of bundles (monkey faces)

5. Bundle details Xylem Phloem Sclerenchyma Cortex

6. Alfalfa stem – a dicot

7. Sunflower stem – semi-woody (development of a cambium)

8. TYPICAL TREE TRUNK ANATOMY Wood – central largest portion Cambium – thin area of small dividing cells Bark – outer layer

9. TYPICAL TREE TRUNK ANATOMY Bark to outside Cambium thin! (dark line) Xylem to inside (annual rings visible) Pith in center 

10. TREE ANATOMY 2 o phloem Cambium 2 o xylem 1 o xylem Growth ring Vascular ray Pith

11. CONTRASTING SECTION TYPES Cross Radial Tangential Scanning electron micrograph (x60) of the wood of an angiosperm tree, the beech Fagus sylvatica, showing the 'drinking straw' vessels packed in between the narrower tracheids, and oriented parallel to the long axis of the trunk. Conifers have only tracheids. (Image: Brian Butterfield and Brian Meylan)

12. PINE CROSS SECTION Tracheid cells circular Can see annual rings (cell sizes slowly change) Vascular rays elongate, but not well developed Resin canals visible

13. CROSS SECTION

14. PINE RADIAL SECTION Tracheid cells elongate Can see annual rings (cell sizes slowly change) Vascular rays of elongate cells, but area squared Resin canals visible

15. PINE RADIAL SECTION

16. PINE TANGENTIAL SECTION Tracheid cells elongate, pits visible Cannot see annual rings Vascular rays elongate with circular cells within Resin canals visible

17. PINE SECTION COMPARISON

18. Softwood vs hardwood Resin canals Uniformity of xylem

19. Root anatomy All roots have Endodermis One vascular bundle at center

20. Monocot vs dicot roots Corn (monocot)buttercup (dicot)

21. Root anatomy - details Epidermis Cortex Endodermis Pericycle Vascular tissue