138 REPRESENTATIVE PLANTS 



able, as it i? not subject to wilting and consequent useless- 

 ness. Students are often able to furnish some material, 

 fresh or dry, and it is always a distinct benefit to the stu- 

 dent whenever even a part of the material which he uses is 

 brought in by himself. 



Habitat. Recall where you have seen ferns growing wild. 

 What conditions of moisture and sunlight do they generally 

 need ? What forms do you know by name ? How large or 

 how small have you seen them ? How common are ferns as 

 compared with other plants? 



The Sporophyte 



The leaf, external features. Acquaint yourself with the 

 leaf characters of at least the following forms : 



The Boston Fern (cultivated) and the Shield, Spleenwort, 

 and Brake Ferns (wild). The characteristics which dis- 

 tinguish will be learned when we study the fruit (spore 

 clusters). Observe the general appearance of the leaf (all 

 that part commonly called the fern), and observe that it has 

 two parts, a stalk below, the petiole, and a thin, green, ex- 

 panded, more or less divided blade above. In the Boston 

 fern the blade is once divided into lobes called pf?i7ioe (pinna). 

 In the shield fern the blade is divided twice or thrice, the 

 second division forming the pinmdce (pinnula). Observe the 

 amount of division in any of the ferns furnished. Observe 

 whether the stalk is smooth or bears brown scales near its 

 base. Examine a young leaf not yet expanded. What 

 peculiar form has it? (This form is a characteristic of 

 ferns.) The method of leaf unfolding or expansion is 

 vernatio7i. 



Study the distribution of the veins (venation). A charac- 

 teristic form is the forked or dichotomous, with the vein 

 ends separate. 



The rhizome. Examine the fresh underground stems 

 {rhizome), or the same preserved in some manner. (This 



