N U T R I T I O N.

Truffles are by no means lacking a root. Vegetables usually draw their food from the humus or from living bodies, with whose contact they enjoy, through their roots. This is known to everyone. Spongioles are the absorbing organs (18) and constitute the essence of the root, while the fibers, upon whose tips the spongioles usually sit—though less essential in themselves—multiply the number of spongioles and distribute them to various points of the humus. Parasitic plants, which greedily suck up the humors of another from a single point, are destitute of root fibers, and their entire root is accumulated into a mere cellular tubercle, representing some specimen of a spongiole. This is the case in Orobanche, Lathrea, Viscum, Loranthus, etc., whose root differs so much from the others that these plants are generally called rootless. So it is with the Truffle. The rind of the Truffle, as we explained above, is of a vesicular texture, and is for the most part exasperated by papillae or tubercles (see page 1), which, since they do not differ in internal structure from the tubercles of parasites and the spongioles of other plants, I do not doubt should be considered the true roots of Truffles (19).

While the Truffle, being subterranean, is soaked on all sides by humors, and immediately enjoys a most extensive absorbing surface, it excludes the necessity of fibrils for increasing the number of spongioles; it is therefore covered, if I may say so, with sessile roots. It is consistent with reason that emerged tubers have root fibers (Rhizopogon, Gautieria), but that subterranean Lycoperdinei (puffball-like fungi) lack them (Elaphomyces).

If what has been explained so far holds true, the nutrition of Truffles remains not difficult to conceive. While the Truffle is buried on all sides by the humus, the lymph, flowing around it mechanically through that medium, enters the spongioles and seeks the substance of the peridium or the sporidia-bearing cells, which process it. This cycle is strongly assisted by the veins, through which the lymphatic humor, running along the folds, also pervades the inward-pushed part of the peridium. Hence the nucleus of the veins (thallus) is perpetually turned toward the center of the earth, just as the root in more perfect plants. Finally, the elaborated humor, carried to the sporidia, vivifies, nourishes, and matures them. Bulliard called the humor in which the sporidia swim "spermatic."