Plant World Continued 



225 



usually 64 spores in each sporangium. These spores drop on to the moist 

 earth and grow into a minute plant, by first absorbing moisture, and 

 then, as the osmotic pressure becomes too great on the inner portion, 

 breaks, and sends out a tiny tube (Fig. 122). This process is called 

 germination ( ). Then a smaller tube appears 



close to the spore body growing from the tiny tube just mentioned, 

 and this is the beginning of the root-like bodies, the rhizoids, which are 



B 



Fig. 120. The Ferns and Their Allies. 



A. Fern plant (Aspidium), showing roots, rhizome, and frond: A., section 

 of fruit dot (sorus), showing spore cases, some of which are ejecting their spores; 

 B., portion of a leaflet, showing unripe fruit dots; C, portion of a leaflet, showing 

 ripe fruit dots. (After Strasburger.) 



B. Order I. Salviniales (Floating Allies of ferns). Salvinia natans. 



C. Order II. Equisetales. Branched Equisetum. Equisetum Funstoni, com- 

 monly called "Scouring Rushes," as distinguished from the "Horsetails" (also 

 called Equisetales). The stems of Horsetails die each year and the fruiting cones 

 have no terminal point. 



D. Field Horsetail, showing buds and tubers. 



E. Order III. Lycopodiales (Club-mosses). Common Club-moss, LycopoJiitm 

 clavatum. 



F. Order IV. Isoetales (Quillworts). Braun's Quillwort, Isoetes cchinospora 

 Braunii. 



(A, after Strasburger; B to F, from W. C. Clute's "The Fern Allies," by 

 permission of The Frederick A. Stokes Co.) 



