FLORA OF WASHINGTON AND VICINITY. 33 



Autumnal blooming, in so far as it is peculiar to this climate, may be 

 chiefly attributed to the tolerably regular occurrence here of a hot and 

 dry season in midsummer. This usually begins towards the end of June 

 and ends about the middle of August. During this period in some sea- 

 sons the ground and vegetation become parched and dried up so that 

 vegetal processes in many plants cease almost as completely as in the 

 opposite season of cold. From this dormant state the warm and often 

 copious rains of the latter part of August revive them as do the showers 

 of spring, and they begin anew their regular course of changes. The 

 frosts of October usually cut their career short before maturity is reached, 

 but in some cases two crops of seed are produced. In addition to this? 

 there frequently also occurs a very warm term in November, often ex- 

 tending far into December, and of this certain species take advantage 

 and j)ush forth their buds and flowers. 



VII. ALBINOS. 



Well-defined albinos have been collected of the following species : 

 Desmodium uudiflorum. Mertensia Virginica. 



Liatris gramiuifolia. Sabbatia angularis. 



Ehodondendron uudiflorum. Pontederia cordata. 



Vinca minor. 



The green-flowered variety of Trillium sessile and of Gonolohus ohli- 

 quus are also found. On June 16 of this year I collected Garex tenta- 

 culata on the Eastern Branch marsh, having the spikes completely 

 white, as if etiolated, but not yet mature, and apparently perfectly 

 healthy and vigorous ; indeed the plants were considerably taller than 

 normally green ones growing with them, but they were always either 

 entirely whitened or not at all so. On examination and comparison no 

 other differences could be detected. 



VIII. DOUBLE FLOWERS, ETC. 



Thalictrum anemonoides, Ranunculus bulbosus, Claytonia Virginica, and 

 Bubus Canadensis have been found with the flowers much doubled, as 

 in cultivation. 



Hydrangea arhorescens occasionally has the outer circle of petals ex- 

 panded, as in cultivation. 



RudbecUa fulgida has been found with all its rays tubular but of the 

 usual length. 



on the contrary, this species continues to bloom from May to September, wherever 

 found, from New England to Calif, and yet the fact has not receiv. d mention in the 

 books." He further states, however, that he has called attention to it some years ago 

 in the "Lens." [Since appending this note I have revisited the locality (July 17, 

 iSol,) and find it still blooming with fresh flowers.] 

 Bull. Nat. Mus. No. 22 3 



