Newcombe. Sensitive Life of Asparagus plumosus. 35 
geonasty, as well as diageotropism; but the later writings 1 ) show 
a tendency to refer the change in most plants to diageotropism 
alone, this diageotropism being, in many cases, indnced by light. 
I fail to find anywhere in the literature a case in which the 
plagiotropic declination of a formerly orthotropic shoot may not 
be induced by the action of light. In the seedlings of Asparagus 
plumosus, however, we have such an instance. Raised in darkness 
from the seed, the aerial shoots make as great a declination as tho 
raised in the light. The angles of declination run usually from 
45° to 90°; only one of my 14 seedlings showed its declination 
less than 45°. These angles are abont the same as made by 
seedlings grown in the light; for while the declination of shoots 
growing from rhizomes is almost invariably 90°, that of normal 
seedlings is, in perhaps half of the number, less than 90°. 
This prompt bending of the seedling shoot into the plagio¬ 
tropic position in the dark was a surprise to me. One may assume 
that in phylogeny the appearance of this cnrve is secondary. 
Hence, on the principle that the seedling resembles, more or less, 
ancestral forms, one might expect the seedling in the dark to grow 
erect. The taking of the plagiotropie position in the dark under 
apparently the sole influence of gravitation might be interpreted 
as an inheritanee, and the change of attunement to gravitation 
might be regarded as due to a phasogenic ekphory 2 ) related to the 
approaching cessation of growth. 
Altho it is evident by Observation of seedlings kept always 
in the dark that light can have little if anything to do with the 
diageotropic position assnmed by them, it is just as evident that 
light has considerable influence on the establishment of the dia¬ 
geotropism of shoots grown from rhizomes. It has been pointed 
out that the young orthotropic shoot of Asparagus, growing in 
light, usualty has its vertical plane of curvature determined by 
the direction of light; that is, the positive heliotropism of the shoot 
keeps the tip more or less declined for a Tveek or more before the 
diageotropism makes itself evident, and then the diageotropic decline 
is in the ~same vertical plane as the former heliotropic bend. This 
determination of the vertical plane of curving by light is exactly 
what takes place, according to Czapek 3 ), in the normal declination 
of the epicotyl of Cucurbita pepo. But this is not the only effect 
of light in this phenomen. By reference to the part of this paper 
under the caption, „Behavior of Shoots never in Light“, it will be 
seen that without light, the shoots never attain a fixed plagiotropic 
Position. They begin to make the plagiogeotropic decline in the 
dark, they may decline 15°, 30°, 45° or rarely go nearly to the 
horizontal, but after a pause of a f'ew hours or a few days, they 
invariably erect themselves again to the vertical direction. And 
1 ) Czapek, Weitere Beiträge zur Kenntnis der geotropischen Reiz¬ 
bewegungen. (Jalirb. wiss. Bot. XXXIII. 1898. p. 175.) — Maige, 1. c. 
2 ) Semon, Die Mneme. Engelmann, Leipzig 1908. 
3 ) Czapek, Studien über die Wirkung äußerer Reizkräfte auf die Pflanzen¬ 
gestalt. (Flora. 85. 1898. p. 424.) 
3* 
