Page:Popular Science Monthly Volume 69.djvu/72

From Wikisource
Jump to: navigation, search
This page has been proofread, but needs to be validated.
68
THE POPULAR SCIENCE MONTHLY.

their parasitic roots down through the sap wood of the host to procure their nourishment, the host, not being able to eject them entirety, forms a ball-like excrescence around the juncture of the two plants by the irritable hypertrophy of the tissues thus caused in the host. If the invading plant be pulled out of the growth thus formed, a delicately carved socket will be seen, very much like that of these 'wooden

PSM V69 D072 Pinus showing the wooden flowers of four petals.png

Fig. 3. A Branch of Pinus, showing the 'wooden flowers' roughly divided into four petals.

flowers,' but upon a smaller scale. Thus such a 'flower,' though small and usually upon a large limb, is formed whenever a mistletoe grows upon an oak.

These large 'wooden roses' are, therefore, nothing more than the protective hypertrophied tissue formed by the branches of some host tree when attacked by a parasite, which in this case is a gigantic species of mistletoe, Lorenthus Ladebeckii (Engl.), growing upon any one of several host trees, the principal ones being Citrus medica, and several species of conifers. The Ladebeckii flourishes in isolated zones throughout the western coast of the American continent from northern Mexico to Terra del Fuego, but has never been authentically reported from any other part of the globe.

The one remarkable thing which attracts attention to these growths and causes them to be mistaken for flowers is the great proportions attained by them. The 'stem,' which of course is a limb of the host plant, rarely exceeds an inch and a half in diameter, the parasite evidently not being able to attack other than the younger and more vigorously growing shoots. As long as these can supply the nourishment for the Ladebeckii, it grows, the excrescence upon the citrus becoming larger and larger until the distal portion of the branch dies, leaving the small inner portion of the branch supporting a large ball from which grows the parasite. At the end of a few years, say four to seven, sufficient nourishment can no longer reach the parasite, either because the small supporting branch can no longer carry it, or the protective excrescence has shut it off from the intruder, which therefore drops out, leaving the open, delicately carved formation, which so resembles 'wooden flowers' as to give rise to the remarkable legend above recounted.