and Laboratory Methods. 2611 



Laboratory Outlines for the Elementary Study of Plant 



Structures and Functions from the Standpoint 



of Evolution. 



SUBKINGDOM, PTERIDOPHYTA (HOMOSPOROUS). 



A series of ferns to illustrate the evolution of complex organs from simple 

 ones. 



LV. Ophioglossiiin vi//gatum L. Adder's-tongue. 



Class, Filices. Order, Ophioglossales. Family, Ophioglossaceae. 



This simple fern may be collected in spring and summer in moist meadows 

 and thickets. The entire plant should be dug up and care taken so as not to 

 injure any of the roots. Preserve in 70 per cent, alcohol and press some for 

 herbarium specimens. Although fresh plants are preferable, preserved or dry 

 herbarium specimens will answer very well. 



Sporo/'/iyfe. 



1. Sketch an entire plant, carefully representing the four important regions 

 of the sporophyte-sporangiophore, leaf blade, stem (short upright rhizome), and 

 roots. Do the roots branch ? Note the growing point at the summit of the 

 rhizome from which new leaves are developed. 



2. These four parts may be compared with the organs of a Splachnum 

 sporophyte in a general way as follows : 



a. The sporangiophore with the capsule. 



b. The leaf with the hypophysis. 



c. The stem with the seta. 



d. The root system with the foot. 



3. Study the venation of the leaf under low power. Draw a portion and 

 describe. Study and draw the stomata. 



4. Mount a part of the nearly mature sporangiophore. Draw under low 

 power, showing the sporangia. ITnder high power draw some of the nonsexual 

 spores. 



LVI. Botrychinm simplex Hitch. Little Grape-fern. 



Class, Filices. Order, Ophioglossales. Family, Ophioglossacea;. 



This fern is to be found in moist woods and meadows. 



1. Sketch the entire sporophyte and note the advance in complexity, over 

 Ophioglossum, of the sporangiophore, leaf and roots. 



LVII. Botrychinm liuiaria (L.) Sw. Moonwort. 



The moonwort is found in the northern part of the United States and usually 

 grows in fields. 



1. Sketch the entire sporophyte, showing the sporangiophore, leaf, roots and 

 rhizome. Describe how this plant differs from the preceding. 



