1922] on Biological Studies in Madeira 565 



Indica of the Madeira mountains, whose seeds I have also sent for 

 the same purpose to the warmer regions of the United States of 

 America. 



The Conifer* were represented originally only by two junipers 

 and a Taxus ; and the flora generally, in conformity with that of 

 other oceanic centres, gives ns numerous examples of orders with a 

 single genus and of genera with a single species. 



Let us for a moment glance at the striking Echiums of Madeira, 

 and try to imagine their association with the pretty little Viper 

 bugloss of our British meadows at this season, from which, or some 

 ancient ancestor, the Madeira fruticose examples, E. Gandicans and 

 E. Fastuosum, have developed to adorn our cliffs and precipices in 

 their striking beauty of vivid blue. 



Side by side with one of these is fast becoming naturalized the 

 stately unbranching E. Simplex of Tenerife, its straight stem, 

 8 to 11 feet high, crowded with small white flowers, and the two 

 species remain, year after year, distinct and unblended. 



Now, the common honey bee of Madeira, identical with the black 

 bee of the British Islands, had become so destructive a pest in the 

 Tineyards seventy years ago that the authorities intervened and 

 banished every hive away to the mountains, where, feeding on vast 

 tracts of Vaccinium, and ceasing their depredations among the grapes, 

 they would follow their lawful calling of fertilizing and honey- 

 gathering. Then, in view of the importance of the bee in fertilizing, 

 hearing that the Carniolan bee would not attack fruit, I started a 

 heavy swarm among the vines of my Quinta. The flowering echiums 

 were at once literally beset with the new bee, which seemed to 

 prefer their nectar to any other food which our gardens provide in 

 abundance. I watched anxiously for the issue of this invasion, and 

 found eventually that the new bee had effected a remarkable hybrida- 

 tion of the Tenerife species with pollen from E. Fastuosum, and that 

 the resulting hybrid, still mainly Simplex, had acquired feebly the 

 branching habit of E. Fastuosum, a tinted flower, and in a languid 

 manner the perennial vitality of the Madeira species. E. Simplex 

 dies down after flowering at the conclusion of its biennial existence ; 

 but the hybrids survived long after flowering, and presented us with 

 the most remarkable sight of their helicoid flower cymes — potentially 

 indefinite — and normally 2 or 3 inches in extreme length, unfolding 

 and unfolding, until, trailing on the ground, and still attached to 

 their lingering parent by a thread-like stalk 7 or 8 feet long, ever 

 with an opening flower, death happened at the root and closed the 

 whole episode. The hybrids gave no fertile seeds, but for several 

 generations E. Fastuosum showed traces of contamination with 

 E. Simplex. 



In general botany we recognize twenty or more species of Echium, 

 but there is not one of these to which you can point as a probable 

 ^ancestor of the fruticose forms which characterize the plant in the 



