Our friend Professor Voelcker had some seed of the flax dodder sent to him for analysis, the reason being that, as his correspondent had separated a great number of bushels of this weed pest from a single crop of flax, he was desirous of ascertaining whether it possessed any feeding properties or the reverse; and on this head it is satisfactory to learn that it is considered useless, though innocuous.
It was part of this sample with which we experimented on the mode of growth of dodder, which, although being the dodder of the flax or linseed plant, yet its natural history will doubtless be that of the clover dodder;[8] we shall, therefore, describe the progress of our experiments, and their results.
[8] We are desirous of instituting special experiments on the growth of clover dodder, but have failed to procure ripe seed, the reason being that the seed does not ripen after the clover has been cut down for its first crop.
A. Seed-covering beneath which radicle or young root is pushing.
B. Leafless stem or tendril growing upwards, bearing seed-covering on its apex.
C. Young thread-like plant freed from seed-covering, on the look-out for a foster-parent.
D. Not finding a foster-parent, droops and dies.
Having prepared some finely-sifted soil in a garden saucer, we sowed a small quantity of flax seed with which had been purposely mixed a few of the seeds of flax dodder; this, on being placed in a hot-house, showed the progress indicated in the [diagram].
Our next [diagram] shows the progress of dodder-growth when the parasite has germinated sufficiently near to a young flax plant to be attracted to it. In such case, instead of dying, it seems all at once to be animated by new vigour. The highly elastic thread, which now represents the whole dodder plant, goes through the following stages:—
