46 FERNS : BRITISH AND FOREIGN. 



varies greatly in length, and is either simple or branched ; 

 when very short and branched it forms tufts (ccespitose), and 

 when very long (surculose) it usually climbs on trees 

 (scandent). Very rarely it is erect (subfrutescenf). Its point 

 of growth is always evidently (often considerably) in ad- 

 vance of the undeveloped fronds ; and the fronds themselves 

 are produced singly from special, more or less distant, 

 points on its sides, termed nodes, at which they are arti- 

 culated. 



Sarmentum, a tough slender running stem, rooting like a rhizome, 

 and either epigaeous or hypogeeous, but differing in having 

 the bases of the fronds adherent and continuous with it, 

 and in its point of growth being coincident with, or scarcely 

 ever in advance of, the undeveloped frond. 



Caudex, an erect or reclining (decumbent) stem, either simple or 

 tufted (ccespitose), through the growth of offsets, or rarely 

 sending out long running shoots, which root at their ex- 

 tremity (stoloniferous). It is often very small, scarcely 

 rising above the earth, but generally more or less elevated, 

 and sometimes forms a cylindrical trunk (arborescent), oc- 

 casionally 50 or more feet high, which, in many species, is 

 thickened by the growth of numerous aerial, outgrowing, 

 wiry roots. And it bears a crown of usually adherent 

 fronds, developed in a spiral series, upon its apex. 



FRONDS. 



The fronds of Ferns are either barren or fertile. In the great 

 majority the latter do not differ very much from the former, though 

 they are generally rather narrower in all their parts. But some- 

 times they are very evidently different on the same plant, the 

 barren presenting the ordinary leafy appearance, and the fertile 

 being decidedly contracted, occasionally so much so that the leafy 

 part is entirely absent, or in some the two kinds are combined in 

 the same frond, the fertile portion being contracted, and the barren 

 leafy. 



"When young the fronds are involutely coiled, in the manner of 

 a watch-spring, and gradually uncurl during the period of growth 

 (circulate) ; rarely straight, as in Ophioglossece. 



