« PreviousContinue »
SPECIMENS OF PHYSARUM VIRIDE MAGNIFIED 50 DIAMETERS, SUGGEST EGGS
In the case of many of the slime molds the life history of the particular species has not been completely traced. They provide a subject which invites the attention of the student of zoology no less than that of the inquiring botanist.
This change came at dusk on the day preceding the dawn of our present inspection, and it came at an unseasonable hour, when I was not equipped with a light and when the fast-approaching night began to cloak in darkness the most interesting activities of this curious organism.
THE SILVERY LIQUID BREAKS UP INTO
My early return to the locality was not without its compensation, for an entire colony of sporangia had sprung up over night. But I arrived almost too late to witness the manner of the transformation; for, even as I looked, the silvery splash of liquid light that still remained on the log began to break up into a compressed group of minute pearls. The globules at first were creamy white, but gradually they assumed a cast of delicate pink, and with the change in hue came a slow, though definite, alteration in the form and size of each unit.
The tiny gems were strewn in shapeless clusters of a single layer, as if the contents of some fairy treasure casket had been spilled upon the bark. In several in stances they were so closely crowded that the soft, yielding bodies arranged themselves in geometrical order, like the hexagonal cells of a honeycomb or the facet eyes of giant dragon flies.
Eventually a more fundamental change. occurred. By degrees the developing sporangia increased in dimension along their vertical axes and began to resemble short cylinders standing on end, the topmost part of each being slightly enlarged.
As the columns rose, gathering their substance from the surrounding slime, the globules topping them became less marked, until they completely disappeared when each little sporangium had reached a height equal to three times its diameter.
THE INSECT WORLD GOES INTO ACTION AGAINST THE OBSERVER
Before this stage was reached, however, the sun was more than four hours old and the oppressive atmosphere of the swamp began to assert itself.
The rising temperature set the insect world in motion. Wasps and bees hovered uncomfortably close, respecting my per
son only while I was puffing vigorously at my pipe. Occasionally the sting-bearers would crawl over my face and hands, and although they made no attempt to attack, their presence was distracting, lest I should forget and make an incautious
The mosquitoes, the gnats and buzzing flies, on the contrary, considered my welfare not at all; whole tribes took telling toll of my lifeblood.
Round about, a more attractive crowd appeared. Gaudy butterflies settled lazily upon brilliant blossoms, uncoiled their siphons and thrust them deep into the hearts of flowers. A great moth, startled from its hiding place, flick-flacked its way here and there excitedly, the metallic blue of its wings flashing in the shade like a fragment of the sky.
Grazing the ground in its characteristic low flight, a somber ichneumon fly went hesitatingly by on powerful bronze-black wings, halting to explore some bit of ground or likely plant, in its search for prey.
Now my nostrils were assailed by the heavy odor of a near-by stinkhorn toadstool, which loosed its strangling stench on the humid air.
THE CLIMAX OF THE TRANSFORMATION SPECTACLE
Despite these distracting factors, I continued to watch the growing columns of the slime molds. The nascent sporangia were now becoming diffused with a deeper tone of pink, particularly at their bases.
For the first time, I noticed that the cylinders were no longer in actual contact with the wood; a hairbreadth space had intervened, and they were slowly being elevated into the air, as the stalks began to form.
These threadlike stalks, which were of a deep tone of garnet red, gradually reached a length of one-half the entire organism and expanded like cups at the top.
The flaccid group had by now lost its compressed, or honeycomb, appearance; each individual unit stood staunchly upright, independent, seemingly apart from its neighbors, yet in crowded contact with them. The surface now began to dry, and
In this stage the plasmodium moves slowly about in search of food and moisture. Later it will develop into a beautiful object, similar to one of those shown in the Color Plates.
simultaneously the iridescent covering of filmy skin began to peel into shreds and
On the wings of the imperceptible movement of heavy swamp atmosphere, these fragments vanished, and-presto! there was revealed that wonder of wonders, a
gauzy tangle of spore-laden threads called the capillitium.
The sporangia were now fully formed. There was no further increase in the length or breadth of any part. The plasmodial slime was completely exhausted. The microcosmic spectacle was at an end!
Notice of change of address of your GEOGRAPHIC MAGAZINE should be received in the office of the National Geographic Society by the first of the month to affect the following month's issue. For instance, if you desire the address changed for your May number, the Society should be notified of your new address not later than April first.