OF THE AME^^TUM. 189 



The name of Livolucrum is applied by Gleditsch 

 to the menibrane covering the fructification of ferns, 

 /. 144, 145; nor have I, in studying this part with 

 peculiar attention in order to reform the genera of 

 these plants, see Tracts relat'mg to Natural His- 

 torif, p. 215, found reason to contrive any new 

 appellation. My learned friends Willdenow and 

 ■ Swartz have judged otherwise, calling this mem- 

 brane the indusiiim, or covering; which seems to 

 me altogether supei'fluous. See its various forms in - 

 EngL Bot. t, 1458—60, 1150, 1159, 1160, &c. 



3. Amentum^ f, 14G. Catkin, denominated by authors 

 before Linnnsus jw/w.y, iiucaynentum, or catidus; con- 

 sists of a common receptacle of a cylindrical form 

 beset with numerous scales, each of which is accom- 

 panied by one or more* stamens or pistils, so that 

 the whole forms an aggregate flower. The recep- 

 tacle itself and the bases of the scales are firmly 

 united, and the whole catkin falls off entire, except 

 that in some instances the upper part of each scale 

 withers away, as in the Willow genusj SalLv, EngL 

 Bot. t, 1388—90, 1402 — 4, &c., the seed-vessels 

 in that genus being quite distinct from the scales. 

 In others, the whole scale remains, enlarges, hardens, 

 and protects the seed, as in Pijius, the Fir tribe. 

 Such is the case with catkins of fertile flowers, 

 which are necessarily permanent till the seed is ripe; 

 barren ones fall as soon as the stamens have per- 



