258 BOTANICAL GAZETTE [APRIL 
; Rupture by sulphuric acid 
As long ago as 1896 Rostrup (45) of the Danish Seed Con- 
_ trol found that concentrated sulphuric acid treatment hastened 
‘ germination of hard seeds of Lathyrus sylvestris. ToDARO (50) 
used concentrated sulphuric acid on red clover seed with beneficial 
results. He also reported that various weed seeds, including those 
of Rumex crispus, were all destroyed by a brief immersion in 
sulphuric acid. Accordingly, to determine more certainly the réle 
of seed coats in the germination of the five kinds of seeds, they 
were treated with concentrated sulphuric acid for periods previously 
determined, carefully washed in carbonate of soda solution, then 
in distilled water, and placed in germinators as previously described. 
TABLE V 
TREATED WITH CONCENTRATED SULPHURIC ACID] UNTREATED 
i el $. ree da 1. 
sens Minutes in In light |Indarkness 
H.SO, 8 days 8 days 
8 days To days 8 days 
(x) (2) (3) 
Nicotiana Tabacum....... 0.5 ° ° ° 42 ° 
Nicotiana Tabacum....... I ° ° ° 42 ° 
Verbascum Thapsus...... 0.5 ° ° ° 72 ° 
Verbascum Thapsus...... I ° ° ° 72 ° 
Daueus Carota:: 22... 0.5 23 8 fe) 31 25 
Daucus Carota-). 2.6.4.3. I tN 6 ° 31 25 
Rumex crispus.... .. . 6 27 37 17 88 ° 
MINOX CrIBDUS 65. Gs 2S. 8 6 59 ° 88 ° 
Oenothera biennis........ 8 38 41 78 ° 
Oenothera biennis........ Io I 19 23 78 ° 
Table V indicates that treatment of seeds of Rumex crispus and 
Oenothera biennis with concentrated sulphuric acid yields an 
increased percentage of germination in darkness. Treatment with 
concentrated sulphuric acid for longer or shorter periods than 
indicated gives no better germination of the seeds in darkness. In 
Daucus Carota there is apparently an injury. This experiment 
indicates that light acts on the coat of Rumex crispus seeds, and 
points in that direction in case of seed coats of Oenothera biennts. 
These results in the main agree with those of the experiment on 
abrasion of coats. They confirm the results with seeds of Rumex 
