Lilac-pink (H11) flowers, VII–IX; dark green foliage; spreading habit; height 10–15cm; spread 31–45cm. This is fairly typical of the plants of Mackay’s heath seen in Connemara, and it is named after the schoolmaster who first drew the attention of botanists to this species in the 1830s. However, there is no evidence it has any direct connection with him. Often listed as ‘William M’Calla’.