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the bark as an impalpable film of reddish dust and leaving on my skin a tinge of ruby russet.


I brought my powerful pocket lens to bear upon the dainty individuals. Each unit, although actually less than a quarter of an inch in height, resembled, in the focus of my strong glass, a miniature morel, a small mushroom, though more marvelous than any I have ever seen.

Of the total height, a third was taken up by a slender stalk which at its base was attached to the bark. Surmounting this stalk was a cuplike expansion, which in turn supported a large, dense, elongated cluster of tangled threads-the sporangium (spore case).

That was all. Simple in form, in detail unadorned; yet how impressive! In the case of some individuals the sporangium was immature, as was evidenced by the filmy, iridescent membrane inclosing them. In others this membrane had burst and was still hanging in shreds, disclosing the compacted mass of spores within the network-indescribable in tint, in translucent texture, and in graceful dignity of form.

For want of a better term, I have called their color red. It was one of those rare reds, such as is produced by Nature only in her most delightful moods, as in the rosy reflex of a winter's dawn or in the evening glow that in summer oftentimes transfigures the world as well as the face of the setting sun.

I doubt if any other natural object has a color precisely like these slime molds. It is a red that is almost purple, yet not purple; it is a nuance of red, intriguing, ineffable, that leaves one guessing whether he sees a vibration of color or is receiving only a hazy, illusive impression.


At one edge of the colony the slime. molds were less crowded and, it seemed, less mature. In this place was visible a thin patch of glair, about the size of the palm of my hand, which glistened in the shadowy retreat like a filmy layer of silver-leaf (see page 443).

This patch of slime was significant. It was the last trace of a much larger portion that I had been watching for several

days. Even had its nature been unknown to me, I should readily have divined the reason for the diminution of its size because of an event that was now taking place before my eyes-the long-anticipated transformation of the slime into the colorful colony of pretty sporangia just described.

When, a few days earlier, I had been prowling through the swamp, chance brought me upon the log. At that time it was mostly bare over the area now occupied by the slime molds, except for an exceedingly delicate and almost invisible pellicle of a creamy texture which caught

my eye.


After studying the filmy mass I had become aware that it was moving. Spreading out fan-shaped, it advanced its borders almost as slowly as does the hour-hand of a clock. The rest remained stationary and was connected by a cordlike vein that led into a minute crack in the log.

As the advancing edge seemed to be the only part in motion and the area of the mass meanwhile was increasing, it was evident that the materials for this augmentation were coming from within the log by flowing through the vein.

I realized that a migration was taking place that this curious mass of glair, which normally lives and grows in darkness in moisture-laden tissues of decaying wood, had arrived at the period of its existence when it must reach the outer air and light to reproduce and to enhance the favorable distribution of its spores.

During my visits on succeeding days, the only observable changes had been in the increasing area of the slime and in the shifting of its location. It had wandered, crossed and recrossed its path on the tree trunk, leaving a well-defined trail of organic refuse over its course. Yet slowly and continuously it had kept on the move, like some lost creature uncertain of its way, groping aimlessly about, apparently without other purpose than to follow the most fortuitous route. But in none of its excursions did it travel more than a yard along the length of the log.

Finally its traveling ceased and it began. to separate into pellucid particles somewhat smaller than rice grains.


National Geographic Society

WILLIAM CROWDER Painting from life by William Crowder


The delicate, funguslike organisms known as myxomycetes or mycetozoa are common in all the moist, wooded regions of the earth. Whether they are to be classed as plants or animals is a question upon which scientists are not yet agreed, although the organisms have been the objects of study for nearly 200 years. The above species is the Leocarpus fragilis, magnified 30 diameters.

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With few exceptions, the sporangia (spore cases) of slime molds are seldom more than a quarter of an inch in height, but while their minuteness renders the individuals inconspicuous, the habit of grouping into colonies oftentimes makes them an imposing spectacle. This species, Fuligo septica, enlarged 11⁄2 dianieters, is world-wide in distribution.



The spore is to the slime mold what the seed is to the higher or flowering plants and the egg to the higher animals. Like the spores of
mushrooms (see the National Geographic Magazine for May, 1920) and of ferns (see the National Geographic Magazine for May, 1925),
the spores of slime molds are microscopic bodies which germinate after coming into contact with water. But unlike the spores of true
plants, which develop directly into other plants, the spores of the slime molds produce first an organism, a small colorless speck of pro-
toplasm, which in a short time assumes an elongated pearlike form, carrying at its smaller end a thread or lash, which it whips around in
the water somewhat in the manner of a traction propeller, thus carrying the microscopic organism into moisture-laden food precincts.

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Individuals of this species (globuliferum) resemble tiny beads of porcelain or pearls strewn over dead leaves or wood. Enlarged 40 diameters. The sporangia of certain others of the same family are an intense black and nod at the end of hairlike stalks, reflecting from their glossy surface the blue of the sky; still others collect in groups and strike the eye with a startling shade of scarlet, staining the bark on which they appear like a splash of blood.

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