TERNS OF ECOISrOMIC PLANTS. 171 



ancient Egyptian, Greek, and Eoman doctors. They are now 

 only employed for giving false importance to horse-medicine 

 and damaged hay. They contain the principle called Cou- 

 marin, whicli is also found in the vernal grass, Anihoxantlmm 

 odoratum, which imparts the pleasant smell to hay. 



Ferns, a common name for a family of plants, botanically 

 termed FiKces, of which about 2500 species are named and 

 described; they are found in greater or less numbers in all 

 regions favourable to plant life, and vary in size and form from 

 that of a blade of grass to lofty trees 50 or more feet in height, 

 terminated by a crown of finely -cut leaves, termed fronds, 

 often 15 or more feet in length. They are reproduced by seeds 

 termed spores, which are generated on the under side of the 

 fronds, or in spikes formed of contracted fronds. Having 

 therefore no true flowers, tbey belong to the grand division 

 termed Cryptogams or flowerless plants. It migbt be ex- 

 pected that, in such an extensive and widely -distributed 

 family of plants, many of them would possess useful pro- 

 j)erties, but such is not the case, few being useful either as 

 food, medicine, or in the arts. One of the most important food 

 products furnished by ferns is the underground stem or 

 rliizome of Pte7-'is aqmlina, widch, under different forms, is 

 common and abundant in most countries {see Brake). In ISTew 

 Zealand and other islands of the South Sea, where tree ferns 

 abound, the centre of the stems of Alsojphila efceUa and Cyathca 

 medidlaris consists of a mucilaginous pith, used as food, as also 

 the thick mealy foot -stalks of Angioptens eveda, a fern very 

 abundant throughout the tropics. The most important in 

 medicine is the common Male YeruZccshxa Fzhx-mas (which see). 

 During the last fifty years ferns have come into high favour not 

 only as ornamental plants, but also as competition plants at 

 horticultural exhibitions, for whicli prizes are awarded, which 

 have been the means of raising the value of certain kmds, vary- 

 ing from £1 to £50. The introduction and cultivation of ferns 

 has conseq^uently become an important branch of commerce. 



In 1823 the collection in the Eoyal Botanic Garden, Kew, 



