60 Proceedings of the Boyal Irish Academy. 



out in 1908, the trees in this plot averaged 29 feet in height and 13f inches 

 in girth at breast-high when measured in August, 1916. This astonishing 

 vigour of growth is very evident when comparison is made with an adjoining 

 plantation of pure Japanese larcli, the trees of which are considerably shorter, 

 though they are two yeai-s older, having been planted in 1906. There seems 

 to be no doubt that these first generation hybrids always exceed in vigour 

 both the parent species. 



All the specimens obtained from Dunkeld and Murthly seem to be 

 uniform in their characters, indicating a first cross between two pure species. 

 It is possible that some of the seed of the mother trees may not be always 

 cross-pollinated, and in that case the resulting seedlings would lie identical 

 with L. Irptolepis ; but no instance of tliis came under our notice. 



It is now proposed to apply* to the " hybrid Dunkehl larcli," Larix 

 Icplolcpis $ X Z. cHvopafa 5 , the name Larix eurolepis, A. Henry ; and to 

 give in the succeedini; pages the results of a careful study of the material 

 obligingly sent by Mr. A. Murray, forester at Murthly, and Mr. D. Keir, 

 forester at Dunkeld. 



Hefore giving a description of the hybrid larch, it is necessary first to 

 slate clearly and at considerable length how the two parent species plainly 

 diller in their twigs, leaves, tlowere, and cones ; but it is convenient to 

 postpone till later our account of the peculiar distinctions that are visible 

 under tlie microscope iu the sections of the leaves of the parent species and 

 of the hybrid. 



1. Parent Species («) Ticigx. In Larix europaea the twigs in tlieir first 

 year are glabrous, green, and without waxy bloom ; becoming in the second 

 year greyish-yellow with the tips of the pulvini tinted orange. Buds golden 

 brown, not resinous ; axillary buds not oveilapped at the base by the apex 

 of the subtendijig pulvinus ; terminal buds surrounded by mucronate scales. 



In Larix leptolepia the twigs in the first year are covered with a waxy 

 bloom, and usually bear long brown hairs, either dense or scattered, but in a 

 considerable proportion of individual trees entirely absent or cast early in 

 the season. In the second year the twigs are red, brilliant in tint on tlie 

 upper surface, duller on the surface directed towards the ground and in 

 tlie shade. Buds reddish-brown, very resinous ; axillary buds overlapped 

 at the base by the raised apex of the subtending pulvinus ; terminal buds 

 surrounded witli partly acute, partly mucronate scales. 



' Larix eurolepu, A. Henry, hybrida nova inter Laricem ltptolepidem> et Laricem 

 riiropoeaii): arbor rubuHtA .illvrius fuliis liujus raiiiulis: bracleis floruni femiii.irum rosci.s 

 ut specioi ouro{>aeao, seel rotlcxis ut spociei japonicae : strobilis maturis etiaiii mcdiis, 

 aioiilibus speciei earopi-jAe forma coaica ; squimts lazb, loviter reflexis : pedunculo 

 davo. 



