300 General Notes. [May, 
lower lip had a sulphur-yellow spot. Sorby, in 1873, showed by the spec- 
troscope that diminution in the amount of light prevents the formation 
of red coloring matter in the corolla of wall-flower, and changes the 
character of the yellow coloring matter. Askenasy was familiar with 
these facts last summer when he commenced a series of experiments, the 
results of which have just been published. He concludes that many 
flowers need the light in order to acquire their normal color, but others 
are quite independent of it. This difference may be referred in some 
cases to defective nourishment of the plant kept in darkness, but this 
cannot explain all. The observations can be so easily made that we 
suggest to our readers a repetition of some of the experiments. The 
plants which gave the most striking results were Prunella, Silene, An- 
tirrhinum, Pulmonaria, Hyacinthus, and Tulipa. = 
Totmrza MENzresu, of Oregon (a curious rather than handsome 
saxifrageous plant, related to Tiarella), propagates naturally and freely 
by adventitious buds, produced at the junction of the leaf-stalk with the 
blade, in the manner of Begonia. We have five live plants that show 
this, sent by Elihu Hall, of Illinois, who calls our attention to the pecul- 
iarity. He states that any of the leaves may be taken off and used suc- 
cessfully for propagation. — A. Gray. 
Mr. W. F. Fuint sends good specimens of Astragalus Robbinsii Gray, 
from the limestone region about Queechy, N. H. 
Rate or GROWTH or Agave Scares. — July 10, 1870. I measured 
a scape of Agave sisalensis to-day, and made two transverse slits with 
the point of my knife, six inches apart, one above the other, and not far 
from tip of scape. 
July 17th. The tip of scape is to-day 41} inches higher than it was 
on the 10th, and the upper incision is 3} inches and the lower one gof 
an inch higher than they were on same day. 
July 22d. Three other plants measured to-day, whose scapes are re- 
spectively 30, 20, and 16 inches high, ' i 
July 25th. In the last seventy-two hours the scapes have grown M 
height 177, 124, and 10} inches, respectively. 
Two transverse incisions were made, one 184 inches from the ape* 
of scape, the other 18 inches below this; the upper one has ascended 
34 inches, and the lower one but ï% of an inch, : 
July 29th. Scape of No. 1 has ascended (its tip) in the last six ay 
39 inches, and No. 2, 24 inches. (No. 3 was not measur 
ed.) he 
August 5th. Tip of scape of No. 1 has ascended in fourteen days 
71 inches, and No. 2, 70 inches, 
August 22d. No, 1 has, in thirty-one days, ascended 12 feet and anki 
inches, and No, 2, 12 feet and two inches. —N. B. Moore, Manatee: 
Fla 
A "JON 
Tae TEETH or GREEN LEAVES as ORGANS FOR THE SECRETION 
OF NECTAR. — The fact that green leaves secrete a saccharine matter 
