116 LABORATORY AND FIELD EXERCISES 



d. Seasonal life. Are ferns annuals, biennials, or peren- 



nials in habit ? How do they pass the winter ? What 

 is the function of the rhizome in the winter season ? 

 Be able to indicate the seasonal activities of the fern 

 in a manner similar to that outlined for the bean, 

 clover, and apple in Part I of the text. 



e. Summarize the principal seasonal activities of the fern 



plant during summer, spring, and winter, indicating 



the main plant organs concerned. 



8. Anatomy of maidenhair fern (Adiantum). Examine with 

 a hand lens and low powers of the microscope trans- 

 verse sections of a fern stem, or rhizome, like that of 

 Adiantum, with a tubular vascular cylinder of phloem 

 and xylem. 



a. Gross arrangement of tissues. Do you find the same 



general tissue layers in the fern rhizome as in the 

 herbaceous stems studied earlier in the course ? 

 (Consult figures and text discussion on herbaceous 

 stems.) Are there the same general subdivisions of 

 the cortex into stereome and storage tissues, and of 

 the vascular ring into phloem, cambium, and xylem 

 as in herbaceous stems ? Note the relative width of 

 the cortex, vascular cylinder, and pith in the fern 

 and in herbaceous and woody stems. 



b. Leaf traces and leaf gaps. Study sections of a fern 



rhizome cut through the point of exit of a leaf. 

 (1) Is the vascular cylinder broken, forming a break, 

 or gap, with a small leaf bundle (the leaf trace) 

 in section opposite the gap ? Consult the text 

 descriptions and fix clearly in mind the nature 

 and relations of leaf trace, leaf gap, and the vas- 

 cular cylinder as a whole. See also the text 

 figures on the anatomy of Adiantum. 



