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an unattached plant. Nevertheless, we cannot assert for 

 this reason that it arose from a spore, since bud or offset 

 sports exist, and the connecting link between the normal 

 parent and the "sport" offset may have long since rotted 

 away, or its evidence destroyed in the process of separation. 

 Experience with spore sowing indicates the probability 

 that "sports" usually arise from spores or seeds, since 

 numerous remarkable forms have thus originated under 

 culture. On the other hand, a case came under our own 

 notice where a single frond base of a hartstongue produced 

 two buds, which subsequently developed into two extremely 

 dissimilar forms; while, conversely, a sowing from a wild 

 " sport" of the same species of a merely sagittate multifid 

 type, gave nine plants of a triple-headed corymbose form» 

 constituting the extreme development of the parental type ; 

 the two merely sagittate basal lobes with divided tips, and 

 the multifid heads developing such dense heavy crests as 

 to absorb and obliterate the normal strap-like portion. 

 Had such a form arisen in the vicinity of the parent, a 

 gradation would have existed, but would hardly have been 

 suspected owing to the great difference. 



As much may be said of all improved or extended types 

 which have been obtained under culture by seminal selec- 

 tion, but the fact remains that the most careful search in 

 the vicinity of marked sports has always resulted negatively 

 as regards intermediate forms indicating gradation. I have 

 so far treated of constant variations, i.e. sports which 

 retain their form under cultivation, and reproduce them- 

 selves truly for generations ; but inconstant sports are 

 frequently found, in which the variation is partial, thus in 

 the Kalothrix variety of athyrium there is always a 

 tendency to revert partially, when, too, the spores are 

 sown there is always a percentage of the assumed 

 parental form, which, however, never, so far as we know, 

 shows the Kalothrix type. 



