THE SECRETAKY'S PORTFOLIO. 453 



vitality, and l)est bear exi)osurc to sen water. Largo genera have a slightly 

 greater dispcr?i(jii than small ones, and variable species than those not espe- 

 cially so. 



WHITE-LEAVED PLAXts. 



It is well known that plants of various kinds, through disease or other causes 

 which sometimes become hereditary, throw out white leaves and, indeed, whole 

 branches. "Wlien this extends to the whole plant, however, it immediately dies. 

 Mr. Peter Henderson, in the American Agriculturist, relates the following in 

 this connection of a geranium : 



*' A few days ago, being in the greenhouse of one of our well-known florists, 

 he showed me, growing among a mass of 'Smilax' foliage (MxjrsipJiyllum), a 

 strong, vigorous shoot of a geranium with stem and leaves as white as snow. I 

 was perfectly nonjilussed for a few moments, as on examining the root there 

 was apparently no shoot except the white one, but on scraping the soil oS for a 

 couple of inches, I found the waggish owner had trained a strong shoot nearly 

 six feet high beliind the screen of smilax, which at once accounted for the 

 healthy condition of the wiiite shoot. The plan was ingenious, and was done 

 in such a way that, had the florist been dishonestly disposed, he miglit readily 

 have found a purchaser, as his wliite braiicli had nearly all the vigor of the 

 green shoot. If we once detach the white shoot from the life-sustaining green 

 portion, death to the white is only a question of time, — and very short time, too. 



ON THE DIURXAL OPENING OF FLOWERS. 



Mr. Thomas Meehan, at a recent meeting of the Academy of Natural Sci- 

 ences, Philadelphia, offered some interesting remarks on this subject. Some 

 plants have been regarded as floral barometers, for it would seem that some 

 plants opened their flowers at particular hours of the day, and meteorological 

 conditions do not appear to influence tlie time of opening. The Portulacca 

 oleracea, common purslane, opened about eight, and by nine had performed all 

 its functions; while a closely allied plant, Talinum Teretifolium, opened at one 

 p. M. and was closed by three. In grasses, CyperacciB, and some rushes, the 

 floral i)arts were very exact in their time of opening. In the plantains (Plau- 

 tago) the pistils appeared a day or more in advance of the stamens, and these 

 last appeared at about a regular time in each day. In Luzula campestris, the 

 wood forms, he had by a series of observations timed it exactly. Before nine 

 the anthers were perfect, but by ten had all been committed to the winds, and 

 only dried membraneous matter remained. 



Mr. Meehan says the popular impression of light and moisture as agents la 

 their behaviour had seemed to receive a tacit scientific assent. It was clear, he 

 thought, there was a more powerful agency underlying them, and it was per- 

 haps a gain to science to be able to see this, though in so dim a light. 



