THE FLOWERING OF AGAVE SHAWII. 317 
VI. THE FLOWERING OF AGAVE SHAWIL. 
FroM THE TRANSACTIONS OF THE ACADEMY OF ScIENCE, oF Sr. Louis, 1877, Vol, III. pp. 579-582; pp.1-4 OF REPRINT. 
In May, 1876, Mr. Shaw received from San Diego, Cal., through the kind offices of Messrs. 
Hitchcock and Parker, a full-grown specimen of the fine species named for him. In June the new, 
innermost, leaves became more slender and their marginal teeth smaller. Early in July the flower- 
ing stalk began to rise. Regular measurements of its growth were made by Mr. Gurney, the super- 
intending gardener, at 7 o'clock A. M. and at 7 Pp. M., from July 8th to September 5th. I have 
divided this period of 60 days into 6 decades, and have added the mean temperature and the fall of 
rain (at my station, 3 miles northeast of the garden) of each decade. The following table exhibits 
these data: — ; 
Amount of Growth in Ten Days. 
1876. 7P.M.-74AM, 7 AM.-7 P.M. Total. Mean Temp. Rainfall, 
July 8-17 2? in 2 in 4} in 82°.8 1,26 in 
18-27 Pes 2} 52 -& 77°.4 ite > 
“6 28-Aug. 6 4} “ 3} “ 8} “ 69°.1 Cin 
Aug. 7-16 c. 4} “ ne. 78°.3 hol 
“17-26 a 4 “ ei 79°.1 2:21 * 
“  -27-Sept. 5 43 “ o 7 * 72°.6 eye Go 
duly G-Sepe. 5. 2 Foes 6 SS eee i 19 in. 46} in. 
The table shows that the night-growth (including the morging hours) was in every decade 
larger than the day-growth, and in the whole period surpassed it by 16 per cent., the former amount- 
ing to 58, the latter to 42 per cent. 
It is further seen that the largest advance was made about the middle period, or from the 3rd 
to the 5th, and mostly in the 4th decade. After Sept. 5th the growth diminished rapidly, about the 
end of the month the head began to swell, and 3 months later the first blossoms opened. 
The table also proves that the temperature of each decade did not have any material effect on 
the growth of the stalk ; in the warm weather of the first two decades it grew much less than in the 
cooler 3rd period. 
The largest growth in 24 hours, 1} inches, took place in the 4th decade, Aug. [580 (2)] 
10th-11th, mean temp. 78°; while on Aug. 18th, with mean temp. 84°, the growth is 
marked only } inch, and Aug. 23rd and 25th, mean temp. 85°, it amounted to 1 inch and ? inch 
respectively. 
The quantity of rain had apparently little or no immediate effect, as it was pretty evenly dis- 
tributed through the whole period. 
The full-grown scape measured 54 inches to the base of the panicle, which, when fully devel- 
oped, was itself 21 inches long and a little wider, and consisted of 19 branches, the lowest ones the 
longest, somewhat S-shaped, and horizontal, with the end turned up. 
About Newyears the lower branches of the panicle, which thus far had formed a pointed club 
covered by the large bracts, began to’straighten out, while the upper ones with their bracts yet 
formed a large cone. The first flowers opened on the lowest branch on Feb. 5th; the innermost 
ones of each cluster developed first, the others flowering in quick succession, so that all the flowers 
of a bunch were in bloom within about three days. Two or three weeks later the plant may be said 
to have been in fullest bloom, though the lower clusters were passed and the uppermost not yet 
open. These last flowered about March 18—20th, so that the flowering period (at this season and in 
a greenhouse) occupied from six to seven weeks. 
