TRICHOMANES RADICANS. 291 



In accordance with the views previously urged, I have en- 

 deavoured to compare the most mature and perfect fronds 

 from each locality, and the results appear to he the following : 

 — 1. That the specimens from Glouin Caragh are far more ma- 

 ture and fruitful than those from Killarney : it is a rare thing 

 to obtain specimens from the latter station in a thoroughly 

 mature state ; I think I may say that not one plant in many 

 hundreds attains the perfect development and fruitfulness dis- 

 played by the Glouin Caragh plant. But, 2. I find that the 

 most mature of the Killarney specimens most recede from the 

 Glouin Caragh specimens, a circumstance rather opposed to the 

 sujjposition that the two are identical, since in general we find 

 ferns develojjing their specific diiferences more strikingly as they 

 approach perfection. 3. The length of receptacle is another 

 test of perfection : the Killarney plant, grown at Killarney, has 

 a receptacle of very different length ; in the most perfect speci- 

 mens it is at least four times as long as the involucre, in the 

 least perfect it scarcely protrudes beyond the involucre, and 

 under cultivation it is seldom to be seen at all, thus evidently 

 proclaiming that its length in some measure depends on health, 

 maturity, and a congenial situation. Willdenow describes the 

 receptacle of his T. speciosum as four times the length of the 

 involucre ; and I cannot assert either that its frequent depar- 

 ture from this character at KUlarney proves anything more 

 than that such departure is a testimony of imperfection, or its 

 attaining this character at Glouin Caragh is to be attributed to 

 any other causes than congenial situation. The form of frond, 

 as Mr. Moore of Glasnevin believes, may be capable of great 

 elongation ; but there is no evidence that the relative length of 

 the pinnae is also altered : it appears to be a fundamental cha- 

 racter of a deltoid frond that the lowest pair of pinnae shall be 

 longer than the second pair, the second longer than the third, 

 and so on : and, as far as I am aware, this character is con- 

 stant in cultivation ; at least, I can safely assert that it is so 

 in Asplenium Adiantum -nigrum, A. acutum, and all the deltoid 

 Aspleniums. The apex of the frond is often lengthened very 

 remarkably, but the lower pinnse almost invariably partake of a 

 similar elongation. In lanceolate fronds, the lowest pair of 

 pinnae are usually shorter than the second pair, the second than 

 the third ; and this character, in Asi)lenium lanceolatum, A. 



