KOYAL FERN 



155 



Ferns, but in the genus Lygodium there are species with 

 twining fronds which grow to considerable length. 

 Hooker says that the New Zealand climbing Fern, 

 L. articulatum, has fronds which may grow to a length 

 of nearly 100 feet. 



Marattiacece. — A family which evidently embraced 

 abundant species in remote geological times, and was 

 then probably dominant among the Ferns; now it is 

 reduced to twenty - five species, 

 which are found only in tropical 

 and subtropical regions. 



Osmundacece. — Only eleven known 

 species ; one confined to South 

 Africa, four mostly to Australasia, 

 and the remaining six are found 

 mainly in the temperate regions 

 of the Northern Hemisphere. One 

 species is found in Britain — the 

 beautiful Royal Fern, Osmunda 

 regalis (Fig. 50) —which, alas ! is so 

 much sought after by collectors 

 that it is becoming rarer every 

 year. Some of the fronds bear no sporangia, but those 

 that do are so covered with them as to appear like 

 spikes of flowers arranged in a panicle — hence the 

 common misnomer, " Flowering Fern." 



Ofhioglossacece. — Twelve species, two of which occur 

 in Britain — the Moonwort, Botrychium lunaria ; and the 

 Adder's Tongue, Ophioglossum vulgatum. The pro- 

 thallus is tuberous, with the sexual organs sunk in its 

 tissue; it is always subterranean, and consequently 

 has no chlorophyll; to make up for this loss, it is 



Fig. 50. — Frond of 

 Royal Fern bearing 

 Sporangia. 



