FLOWERLESS PLANTS 437 



let them try to rear some fern plants from the spores. 

 To do this the spores must be kept uniformly damp. Have 

 an inch of wet sand in a small aquarium and lay on this 

 a fragment of mossy flowerpot, thickly dusted over with 

 spores. Cover the aquarium with a piece of glass ; keep 

 the sand wet and watch carefully to see what grows on it. 

 It might be well to set the aquarium in a greenhouse, if 

 one is available, so that it may be kept at a constant tem- 

 perature. If the experiment succeeds, the strangest thing 

 of all will come to light, viz., that the spores do not produce 

 ferns but, instead, tiny little plants, consisting each of a 

 single heart-shaped leaf. This is called a " prothallium," and 

 from the underside of this a little fern will finally grow. 



Mosses. — The mosses are still smaller plants that do not 

 bear flowers but reproduce by spores. These are often 

 borne on slender stems in little capsules. A collection of 

 as many of the common sorts as the children can find may 

 well be transplanted to the fern bed. There are 6750 

 species known. How many different kinds can the chil- 

 dren find in their school yard ? 



Liverworts. — These are little mosslike plants, but their 

 stems are always flat, or, in other words, carry a leaf-like 

 expansion on either side. Their fruiting capsule opens by 

 two or four valves and never by a lid such as we find in 

 the mosses. There are several beautiful little plants of 

 this kind well adapted for the school aquaria. How many 

 different kinds can the children find ? 



Lichens. — These are a step lower in the scale of plant 

 life. They have no stems but are leaf-like growths, gray or 

 yellowish green, on rocks, boards, the bark of trees, or the 

 ground. Their spores are borne in little cups on the surface. 



