6 L ENGLISH BOTANY. 



other, and are more developed on the lower side than on the upper ; 

 their texture is very firm, and their surface throws off rain or dew 

 without being wetted. The veins are either given off from the midrib 

 in pairs or divide immediately after leaving it, and are again often 

 once or twice forked, the ultimate segments running into the notches 

 between the extremely minute serrulations, and not into their apices. 

 The fronds begin to develope in May, and perish with the first sharp 

 frost. The fertile fronds have from 2 to 6 of the lower pair of pinna? 

 quite like those of the barren fronds, but the upper ones have the 

 pinnae cut down to a winged midrib, from each side of which herba- 

 ceous processes are given off, round which the sporangia are 

 clustered. These metamorphosed pinnae are from \ to 1^- inch 

 long ; they are at first green, afterwards olive-yellow, and ultimately 

 they become of a rusty-brown colour. The spores are green while 

 they are capable of germinating, but become pale yellow when they 

 have lost their vitality. 



This plant has no varieties, properly so called, found in Britain ; 

 cristata and interrupta, Moore, being malformed states or monstro- 

 sities. It sometimes occurs with the rachis divided or with the 

 leaflets lobed and crisped. Not unfrequently on the fertile fronds 

 some of the barren pinnae are fertile on one side, and in this case 

 the opposite side is divided into rounded lobes ; this lobing evidently 

 being the first stage of the transition from the barren to the fertile 

 pinnules. 



Royal Fern, Flowering Fern, or Osmund Royal. 



Suborder II.— H YM E N PH YL L AC EiE. 



Sporangia placed on an extended vein, which forms a receptacle 

 enclosed in an involucre. Each sporangium with a complete 

 obliquely-transverse annulus, opening by a longitudinal slit. 



GENUS IL—T RICHOMANES. Linn. 



Rootstock usually creeping. Fronds more or less translucent, often 

 consisting of but a single layer of cells. Sori marginal, arranged 

 round the lower part of a filiform elongated receptacle terminating 

 a vein. Involucre tubular, undivided, truncate or slightly 2-lipped, 

 often falling short of the receptacle. 



Name from $pi£ (thrix), hair, and /xavds (memos'), loose. 



