110 



DOMESTIC BOTANY. 



from their cases a spontaneous motion may be observed when 

 viewed under the microscope, which continues for some time. 

 They are found in most parts of the world, and are common in 

 this country in ditches and waste places by road-sides. They 

 are the only modern representatives of the remarkable fos- 

 silized remains called Calamites. They have no medical 

 properties, but are imported under the name of Dutch rushes, 

 and are used for polishing furniture, their usefulness in this 

 way being due to the minute particles of flint, or silex, with 

 which their stems are coated. 



The Club-moss Family. 



(Lycopodiace^.) 



Plants consisting of lirm, erect or creeping stems, which 

 are simple, or branched, often flagelliform and pendulous, 



■ furnished with acerose, rusciform, or jungermannia-like 

 sessile leaves. Spore-cases, produced either in the axils of 

 the leaves (Fig. 11, b) or in terminal catkin-like spikes. 

 This family is widely distributed, and is found in both tropi- 

 cal and temperate regions. In the northern parts of Britain 

 they are not uncommon on moorlands and hillsides. They 

 are liable to great variability under different climatic in- 

 fluences, which has led botanists to differ as to the probable 

 number of species, some enumerating upwards of 400, while 

 others do not admit more than half that number. 



/ The spores of Lycopodium clavatum are highly inflammable, 

 / and have been used to produce artificial lightning- flashes in 



■ theatres. Some species from tropical America are highly 

 hygrometrical, as Selaginella-lepidophylla, which grows in a 

 circular roseate form, expanding while the air is in a moist 

 state, but rolling up like a ball when it becomes dry. It re- 

 mains green and acts in this peculiar manner for years after 

 having been gathered. About thirty years ago a great 

 number were imported from Mexico and sold in London 

 under the name of " Eose of Jericho," and more recently as 

 the "Kesurrection Plant." Many species of Selcginella have 



