Page:Popular Science Monthly Volume 33.djvu/388

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374
THE POPULAR SCIENCE MONTHLY.

and conduplicate embryos. The student in charge of "Abnormal Forms in Plants" was able to report a number of monstrosities. All members of the class were expected to contribute, if possible, to this paper upon teratology. A toad-flax (Linaria vulgaris) flower with five spurs instead of one was found; two blossoms of an onosmodium were united into one; a spike of foxtail (Setaria viridis) was divided into seven prongs, and perhaps the most interesting was the finding of many pistils of prairie pink (Phlox pilosa) in which there were four cavities instead of three, the normal number. The ovaries for the whole order Polemoniaceæ, to which the phlox belongs, are tricarpellary, and therefore this is a variation which affects the ordinal description. Under the "Dehiscence of Fruits" the pods and capsules of various plants were studied, including those of impatiens, milkweed, violet, and poppy. Observations were made upon the "sensitive stigmas" of the trumpet creeper (Tecoma radicans), which were found to close in one minute when most active—that is, with freshly opened flowers on a bright, hot day. The "Insects Injurious to Plants" furnished abundance of material for an extended paper, and the investigation of the "Root-System of Corn" enabled a student agriculturally inclined to become familiar, by spade and shovel, with the manner in which the roots of our leading crop are spread in the soil. A contrast between "Grape and Cucumber Tendrils" and a study of "How the Virginia Creeper Creeps" were two subjects which, when specially investigated, enabled the students to become familiar with a number of questions which are not easily answered by a study of books. The "Stipules of Various Plants," when contrasted by making drawings of the living specimens, made a paper of interest to all. The clovers and docks were investigated in particular. The leaf-type of the great rag-weed (Ambrosia trifida) was worked out after an examination of two thousand leaves. An opportunity for some thorough microscopic work was offered in the "Pollen of Ten Kinds of Flowers," and it brought out the difference existing in pollen of the same species as well as contrasts between the fertilizing dust of widely separated orders. "Thickness of Leaves" and the "Polarity in the Compass-Plant" were two topics varying widely in their treatment, one being a general and the other a special topic upon foliage. The "Time required for the Ripening of Seed" was determined in an experimental way. Blossoms of various plants were marked with twine and watched until seeds from them matured. Common purslane required ten days; the cultivated species of the same genus, (Portulacca grandiflora) needed fifteen days, while three times as long was insufficient time for maturing the seeds of Euphorbia hypericæfolia. "The Number of Seeds upon Three Kinds of Weeds" was determined as follows: common dock, 7,556;