180 ECOLOGY 



2. Cut a cross section of a leaf, examine with m.p., and sketch a por- 

 tion extending from the one epidermis to the other. Describe in a 

 few words the characteristics of the leaf structure as compared with 

 any others you have studied. 



D. Note the mode of origin of the peduncle (scope). 



E. Note the position of the flowers. Uses of this. Describe the flower, 

 making a diagram of a longitudinal section and a cross section. 



F. If fruit of the preceding season (in alcohol or formalin) is at hand, 

 describe it. Does it reproduce mainly by seed or by other means ? 



"G. Does this appear to be a sun plant or a shade plant ? Reasons for 

 conclusion. Is it a mesophyte or a xerophyte 1 What is its habitat in 

 a wild state ? Look for insect visitors. What attractions has the flower 

 for these ? Could it be readily pollinated without them ? 



Erythronium. 



A. Sketch the entire plant. 



B. If possible, dig away the earth with a trowel and make a diagram 

 to show how the aerial parts stand above ground and how the un-: 

 derground portion is distributed. Describe the bulbs. Of what use 

 are they 1 



1. Test one for starch, Sec. 12. 



2. Can they be drawn from the ground by pulling the leaves and 

 scape ? Advantage ? Has the plant a stem ? 



C. How do the young leaves emerge from the ground ? What is their 

 position when full grown with reference to. light ? Strip ofi epidermis 

 from both surfaces and study with m.p. Differences ? Explain. 



D. What is the position of the fully opened flower 1 Advantage ? De- 

 scribe the flower. 



1. Make a diagram of the cross section. 



2. Make a diagram of the longitudinal section. 



3. Look for nectar and nectaries. What insect visitors frequent the 

 flower ? 



E. Do many seeds ripen ? Can the plant reproduce itself otherwise than 

 by seed ? 



E. Is the species of Erythronium studied a sun plant or a shade plant, a 

 mesophyte or a xerophyte ? Do its leaves and blossoms mature earlier 

 or later than those of the larger plants amid which it grows ? Advan- 

 tages ? What becomes of the leaves during the summer ? 

 Plants of the lily family are readily distinguished from those of the near- 

 est related families. They differ from the rushes on the one hand in having 

 a well-developed, not membranous, perianth, and from the members of the 

 amaryllis family and the iris family on the other by having hypogynous 

 flowers. The Liliaceoi are divided into about ten subfamilies of very 



