694 



Handbook of Nature-Study 



places, in greenhouses, but the teacher will be very fortunate who is able 

 to show her pupils this stage of the fern. The prothalUum is a stage of 



Christmas fern is below the others. 

 Photo by Verne Morton. 





the fern to be compared to the flower and seed combined in the higher 

 plants; but this is difficult for young minds to comprehend. IliketoteM 

 the children that the fern, like a butterfly, has several stages : Beginning 



with the spore-bearing 

 fern, we next have the 

 spores, next the prothal- 

 lium stage, and then the 

 young fern. While in 

 the other case we have 

 first the egg, then the 

 caterpillar, then the 

 chrysalis, and then the 

 g spore- butterfly. Looking at 



r, spore- . -'^ . - ^ , 



the ripe truit-dots on the 

 lower side of the fern 

 leaf, we can easily see 

 with a lens a mass of tiny globules; each one of these is a spore-case, or 

 sporangium, (plural sporangia), and is fastened to the leaf by a stalk 

 and has, almost encircling it, a jointed ring. (See figure on page 686). 

 When the spores are ripe, this ring straightens out and ruptures the 

 globule, and out fly the spores. By scraping a little of the brown fuzz 

 from a fruiting pinna of the Christmas fern upon a glass slide and placing a 

 cover glass upon it, we find it very easy to examine through the micro- 

 scope, and we are able thus to find the spore-cases in all stages, and to see 



I. 



, sliowi] 



The life of a fern. 



a, pinna bearing fruit : 6, a fruit-dot, enlarged, 

 cases pushing out around the edges of the indusium 

 case, enlarged, showing how it discharges the spores, 



2. Prothallium. enlarged, 



3. Young fern growing from the prothallium. 



