134 BOTANICAL GAZETTE [AUGUST 
TABLE I 
MARCHANTIA POLYMORPHA 
Growth in 12 Growth in 25 
days days Remarks 
Culture solution y 
Length in mm. | Length in mm. 
I. Central zone: 
2 hy SoC SO extracts an. .ss- Sign dese = fe. cas dead after 8 days 
2. Bog water untreated..... sted are Ls5- 2 filamentous outgrowths 
3. Bog w. erated i2.%, ‘ 4 toes! 
4. Bog water neutral....... ae Dears as 
5. Bog water filtered....... 7.5-8 Liss 
6. Bog plant water......... 2 5 
7. Spring Water csc sces 5.6 3° 4 feet 
II. Maple-alder zone: 
1. Bog soil extract..)...... I I -.2 larger number dead after 
2. Bog water untreated..... 0. =935 II 
3. Bog water aerated....... 8 i 12 
4. Bog water neutral. 6 16. 5-14 
5. Bog water filtered....... 5. +8 IO---EI 
6. Bog plant water......... 5 -6 Io -I2 
a period of heavy rains, or when the vessels containing the bog water 
were left uncorked. The differences in growth in the various solutions 
were less marked, showing that the degree of toxicity at one concen- 
tration was entirely different at another. The same is to be said of 
solution no. 6; its toxic character became more marked with increase 
in the time during which the bog plants were under cultivation. 
Briefly summarized, the data thus far agree in showing (x) that 
the contrasts in the relative growth of plants in solutions from the 
maple-alder zone were less marked than those in the solutions from 
the central zone; (2) that the inhibiting factors of bog conditions are 
in part due to the presence of injurious water-soluble substances; 
(3) that the central zone possesses these toxic bodies more decidedly 
than the maple-alder zone; and (4) that in both zones the toxicity 
can be corrected by a method of aeration and by the use of calcium 
carbonate and carbon black. | | 
A series of experiments was next made in the form of bog water 
cultures with various cultivated plants. Half-liter glass jars of the 
Mason pattern were used, and prepared in the conventional way- 
The seeds were germinated in sawdust. Germination in qU Fi 
sand and in paraffin-coated disks of galvanized iron wire was pee 
less satisfactory. Transplanting was done when the plants 
