674 Proceedings of the Royal Irish Academy. 



to examine authentic specimens from the Kew Herbarium, many diffi- 

 culties having been removed by their kind assistance ; while Pro- 

 fessor Perceval Wright also helped me greatly by his kindness in 

 enabling me to examine the authentic specimens in the Herbarium of 

 Trinity College, Dublin. To many other friends — Dr. Moore, of Glas- 

 nevin ; Mr. Fowler, of Castle Kennedy ; Mr. Syme, Elvaston Nurseries ; 

 Messrs. Waterer, Low, and Veitch — my best thanks are also due. 



Parlatore* enumerates and describes eighteen species and two varie- 

 ties in his section Abies, but he seems in some instances to have mixed 

 up two or more anatomically distinct forms under one name. Each form 

 has been carefully described, and a figure of the section of the leaf 

 given, so that this paper may, to a certain extent, be useful in iden- 

 tifying the cultivated species in our gardens and nurseries. 



The species of Abies are generally separated into two groups by the 

 bracts of the cones, which are either long or short. Bertrand separates 

 two groups by the position of the resin-canals. In the present paper I 

 have adopted a geographical arrangement, as I find that the forms 

 most related anatomically are most connected geographically, the 

 outlying forms being generally the most distinct. A great zone of 

 species stretches from North America, by Japan and the Himalayas, to 

 Asia Minor and Southern Europe. 



The section Abies of Pinus is distinguished by having the leaves 

 inserted singly into the stem, by their not being placed on cushions, 

 and by the double fibro-vascular bundle. The second section mentioned 

 in this paper is Pseudotsuga, which differs in having a single fibro- 

 vascular bundle. 



I. Abies, Endl., Parlatore. Genus Abies, Link. Abies, Bertrand. 



1. Pinus {Ahies) hracteata, Don, Trans. Linn. Soc. xvii. 443 ; Par- 

 latore, D. C. Prod., vol. xvi., pars 2, p. 419, No. 88. Pinus 

 venusta, Dougl. Alies venusta, Koch, Dendi'ologie, vol. ii. part 2, 

 p. 210. 



Shoots hairy or smooth. Leaves inserted singly all round the 

 stem, but bent so as to form two lateral rows ; occasionally a few 

 directed upwards. Leaf rigid, linear, twisted above the base, which 

 is slightly narrowed towards the orbicular insertion, widest above the 

 twisted part, then gradually tapering, contracting suddenly near the 

 sharp-pointed apex ; upper surface bright green with no stomata, 

 beneath with a band of stomata on each side of the midrib, there 

 being from 10 to 12 rows of stomata in each band. Leaves from 1^ to 

 2 inches in length, and about vir of an inch wide. Buds covered with 

 pale yellow scales, which are not resinous. 



Transverse section of leaf. — Leaf flattened, ^}j times broader than 

 thick, sides rounded, upper surface gently curved inwards, below with 



* De Candolle, Prodromus, vol. xvi., sect. 2, pp. 419, et seq. 



