64 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. lv. 



rous except at tip, glandular-ciliate, stomatic hairs twice 

 as loDg as in last ; sepals ovate lanceolate, glandular-ciliate ; 

 corolla ovate; ovary spherical, glabrous or very slightly 

 hairy ; style exserted. 



Sub-species 3. — Laicsoniana, Hort. ; leaves slightly revolute, 

 glabrous, and with long non-glandular cilia, stomatic hairs as 

 in last ; sepals oblong, slightly constricted in middle, and with 

 non-glandular cilia ; corolla tubular ovate ; ovary nearly 

 spherical, glabrous ; style strongly exserted. 



Sub-section 4. — Stuarti, Macf. ; leaves half revolute, 

 glabrous, with minute aborted cilia or marginal hairs, 

 stomatic hairs as in two last ; sepals oblong spathulate, 

 with non-glandular cilia ; corolla tubular, mouth open ; 

 ovary depressed, glabrous ; style strongly exserted. 



It is worthy of note that these, like most sub-species, 

 deviate from the type condition, not in one or two structural 

 details only, confined to one part of the plant, but that the 

 whole organism seems to participate to a greater or less 

 degree, in the tendency to variability when such occurs. 

 In attempting -to account for evolutionary change this is of 

 the firreatest moment. 



EXPLANATION OF PLATE I. 



Illustrating Dr Macparlane's Paper on Irish Ericas. 



Fig. \. Transverse section of leaf of E. Tetralix. 



Fig. 2. „ ,, E. Tetralix, sub-sp. Maclcayi. 



Fig. 3. ,, „ E. Tetralix, sub-sp. Stuarti. 



Fig. 4, a. Flower of E. Tetralix, enlarged 7 times. 



h. „ „ sub-sp. Macl-ayi, enlarged 7 times. 



c. „ ,, „ LawHoniana, „ 



d. „ ,, „ Stuarti, „ 



