Vol. 31 Ko? 42 
| BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
4 - DECEMBER, 1904 
3 Notes on the blackening of Baptisia tinctoria 
Jutia T. EMERSON 
Any one who is accustomed to the aspect of our dry open 
fields or sandy hills in the summer can not have failed to notice 
_ the Wild Indigo (Yellow Indigo Broom, Baptisia tinctoria (L.) R. 
Br.). The bright yellow flowers and small three-parted leaves 
make a very conspicuous plant. In early July, on Cape Cod, 
4 before the flowers are open the plants are green, but a few weeks 
_ later a black twig or branch will be noticed, and by August often 
whole plants will be black, even the flowers. If a green leaf is 
7 pinched or injured so that the epidermis is broken, there will pres- 
ently be a black spot at the injury, and it is generally the branches 
ES which have been stepped on or have suffered from an insect bur- 
_ Towing into the stem near the ground, which are the first to show 
a this very characteristic blackening. It is not always due to an 
3 ‘injury ; an apparently healthy plant will be so black that one can 
a easily believe that a good substitute for indigo could be found in 
_ it, and indeed during the Civil War this was tried ; while in drying 
it is well known how dark a specimen it makes. 
The following facts were noted at the Marine Biological Labor- 
atory at Woods Hole, Massachusetts, during some studies made 
at Dr. True’s suggestion and with his kind assistance, upon the 
Cause of the blackening of the leaves of Baptista tinctoria. It was 
thought probably to be due to an oxidizing enzyme, and various 
€xperiments were tried to prove whether or not this was the case. 
It may be well to say a word about the “enzymes. Effront * 
aes 
a ex aaa Ne pc 
* Effront, J. Les enzymes et leurs applications, 63, 64. 1899. 
(The preceding number of the ample Vol. 31, er 11, for November, 1¢04 
1: 581-620, f/. 26), was issued 26 N 1 
1 
