Psoralea argophylla also develops perfect joints but fewer shoots usually make up the crown and it is therefore less conspicuous than P. floribunda. Psoralea esculenta is also a tumbleweed but the writer has not made an examination of the way in which it separates from the thick, tuberous, perennial root.
Fig. 3. (a) Base of a stem of P. floribunda with two cleavage joints. (b) Base of stem showing cleavage surface.
Psoralea floribunda is very abundant in north-central Kansas where the writer has seen great masses heaped up against hedgerows and wire fences. These plants show a most remarkable responsive adaption to an environment of very definite conditions. They have developed nearly every character possible in harmony with the dry and windy plains of the west and may be regarded as ideal prairie plants.
THE SPROUTING OF COCKLEBUR SEEDS.
E. E. Masterman.
In July, 1896, Dr. E. W. Claypole, then of Buchtel College, Akron, Ohio, asked me how general was the belief that one seed of the cocklebur grew one year and the other the next year or later. Inquiry of about twenty of the older residents resulted in procuring no information touching the same. In 1897, I was told by a German farmer that one seed only grew one year and the other later, never both at the same time. A short time after I noticed the statement of A. D. Selby in Bulletin 83, (page 353) Ohio Experiment Station, as follows: “Prof. Arthur has recently shown that only one of these seeds can be caused to germinate the first year, the other always remaining until the second year.” This was a confirmation of the German’s claim, yet I determined to investigate for myself.
I carried on the experiment for three years with the following results:
In 1898, I planted 1000 burs; 917 grew two plants to the bur.
In 1899, I planted 1000 burs; 921 grew two plants to the bur.