LABORATORY AND FIELD EXERCISES 



5. Summary of herbaceous stem structure. Summarize the 

 distinctive characteristics of herbaceous as compared 

 with woody stems, in terms of bark, cortex, vascular 

 cylinder, and pith. 



MONOCOTYLEDONS 



Study transverse sections of stems 

 of monocotyledons. Contrast their 

 structure with that of herbaceous 

 dicotyledons. 



1. Is there a distinct bark in the 



stem of the monocotyledon 

 that you are examining ? 

 a distinct wood ring and 

 pith ? Do you find xylem 

 and water ducts ? Is there 

 phloem connected with the 

 xylem ? What form is as- 

 sumed by the masses of 

 xylem and phloem, and how 

 are these masses (vascu- 

 lar bundles) distributed in 

 the stem ? Where is the 

 strengthening skeletal tis- 

 sue in a monocotyledonous 

 stem ? the storage tissue ? 



2. Drawing. Be able to construct a drawing of a stem of 



a monocotyledon to bring out the contrasts between 

 its structure and that of the stems of herbaceous 

 dicotyledons examined above. 



3. Summarize the differences between the stems of herba- 



ceous dicotyledons and monocotyledons. 



FIG. 15. Structure of a root in 

 transverse section 



e, epidermis ; c, outer layer of 



the cortex (cort) ; x, xylem, and 



p, phloem, arranged radially. 



After Bonnier and Sablun 



