1912] LIVINGSTON & BROWN—TRANSPIRATION 321 
It is at once apparent that in all cases but three (nine out of 
eleven species) our question (page 319) has been answered very 
definitely in the affirmative.* In the case of Prosopis (table IIT) the 
minimum water content, at midday, is only slightly below that in 
TABLE I 
AUGUST 12-13, I9IO 
EVAPORATION PERCENTAGE OF MOISTURE 
Martynia Sida Amarantus 
Pexied Big of paces On basis | On basis | On basis | On basis | On basis | On 
of dry | of entire | of dry | of entire | of dry of entire 
substance | weight | substance| weight | substance | weight 
(A.M.) 
7 0.66 6 417.6 81 452.8 539-4 84 
7s 1.14 7 390.0 80 484.3 83 533-3 | 84 
8-9 2.28 8 394.6 412.5 Soi.3 85 
g-10 2.34 10 384.2 79 353-7 78 500.7 | 83 
Io-II 2.58 tee ee cee ate ee ten 
I-12 2.52 12 357-6 78 355-7 78 490.6 | 83 
(P.M.) 
I2- 1 ky cee! cater 58 een grata: cr er ornay eae eeeaeny (NS trary Lea 
I- 2 3-90 2 339-3 77 338.9 77 395-0 | 80 
3 3-54 Gay Lege Mn ee eee ens 
4-1 37 4.1 $38.4 97" | -R0r3 bs 8 eee 0 
4-5 4.0064 Goa eee i ce eee ee 
5- 6 2.52 6 371.2 79 S47 76 366.6 79" 
O47 Pe ree Mere Beans nee er ie SOE Se 
7-8 1.44 8 551.6 85 407.2 80 591.5 86 
8- 9 1.32 te Se a Sa ae ie ea is Es 
Q-I0 1.08 10 502.7 83 444.4 82 |} 539-2 84 
10-12 0.69 12 461.5 82 47% 82 601.9 86 
(A.M.) 
Ree | 2-885) | ROR 83 457.0 | 82 530.0 | 84 
a5 0.72 rene Pan ae Be reais ee eae Oe Ss 
5-0 0.60 6 455.1 pee Been “a 542.1 84 
the early morning, and the maximum, at 4 P.M., is not markedly 
above the minimum; this case is questionable. One of the two 
definite exceptions to the general rule, Covillea (table III), appears 
to exhibit a reversal of the usual variation in water content. The 
fact that this plant and Prosopis are non-succulent xerophytes is 
™ At about the same time that our experiments were in progress, Lioyp carried 
out his recently published tests in regard to this same matter in Fouguieria. He finds 
and discusses a diurnal fall in the relative water content of the foliage of this plant. 
Loyp, F. E., The relation of transpiration and stomatal movements to the water 
content of the leaves in Fouquieria splendens, a6 World 15:1-14. 1912. 
