186 LABORATORY AND FIELD EXERCISES 



(2) Study and draw leaves of one or more mono- 

 cotyledons to illustrate the form and mode of 

 venation characteristic of the group. 

 b. Stem. 



(1) Aerial and underground stems. Do monocotyledons 



generally have aerial stems as well developed as 

 dicotyledons ? How is this in grasses and cereals, 

 cultivated lilies, narcissus, tulips, onions, iris, 

 palm? Do they have rhizomes, bulbs, and tubers? 

 Study specimens and manuals to determine this 

 point. Are the aerial stems of monocotyledons 

 mostly flower-bearing stems or are they well- 

 developed leafy stems ? Are monocotyledons 

 mostly herbs, trees, or shrubs ? Compare with 

 dicotyledons in this respect. 



(2) Study and draw the underground and aerial stem or 



stems of one or more monocotyledons. Indicate 

 nodes, internodes, buds, and annual increments 

 of growth. 



(3) Anatomy. Cut transverse sections of the aerial stem 



of some monocotyledon and observe the sections 

 with low and high powers of the microscope. 

 Are there the usual tissue areas characteristic 

 of the stems of dicotyledons ; namely, epidermis, 

 cortex, and the vascular ring of phloem, xylem, 

 and pith ? Is there a cambium present ? How 

 do monocotyledon stems increase in thickness ? 

 Draw your section in outline, naming the tissue 

 layers and tissue groups as you think they 

 should be labeled. Draw a single vascular bun- 

 dle and label its skeletal and conducting tissues. 

 Summarize the distinctive features of the anatomy 

 of monocotyledons as for dicotyledons above. See 



