142 GENERAL BIOLOGY 



dug up in winter and placed under a bell jar a week in 

 advance of need) : fruiting spikes of Selaginella, and also if 

 possible, preserved specimens illustrating the development 

 of the male and female gametophytes. 



Study the Equisetum stems in sections (which may be 

 cut with a sharp knife, though very damaging to its edge), 

 locating the chief structural features mentioned in preceding 

 pages. Especially note the distribution of the respiratory 

 parenchyma (of bright green color in fresh specimens) and 

 the breathing pores leading thereto; these latter will be 

 better seen if the epidermis be stripped from one of the 

 "valleys," mounted flat, and studied. 



Study the fruiting spike of equisetum, its constituent 

 scales, the sporangia these bear, and the spores. Mount 

 some spores uncovered to watch through the microscope 

 their hygroscopic activity ; they will respond instantly to 

 the moisture of the breath, let fall upon them while under 

 observation. 



Stud}^ the fruiting spikes and the macrospores and micro- 

 spores of Selaginella, and if there be material so available, 

 study also the male and female gametophytes that develop 

 from these spores. 



The record of this study may consist in notes and draw- 

 ings of the things observed. 



SPERMATOPHYTES, SEED PLANTS, OR FLOWERING PLANTS. 



These are the dominant land plants of our own time. 

 Bryophytes and Pteridophytes we find by searching, but 

 spermatophytes fill the landscape. 



Like the preceding group they present utmost diversity 

 in form and appearance and only agree in a few fundamen- 

 tals of life history. The gametophyte phase is so reduced 

 and difficult of study that we will suit our convenience by 



