The space occupied in synonymy, is therefore by no means wasted. By and by, if we succeed in establishing a nomenclature on which competent judges can agree, a thing not at all improbable, almost now attained, the lists may gradually disappear as having historical value only.
b. Taxonomy, in any field, is of necessity concerned with history. For his own sake, no student can ignore the thought and work of his predecessors. No man ever sees nature in completeness, nor even the small part of the world to which he devotes attention. He needs every possible assistance, especially the observations of intelligent men. The present author rejoices to acknowledge the assistance found in volumes written in Europe during the last two hundred years. Such men as Persoon, Bulliard, Schumacher, Schrader, Fries, are deservedly famous; they laid the foundations of mycologic taxonomy. No student can afford to miss Elias Fries; his genius, spirit and scholarship entitle him to the recognition and sympathy of every lover of the intellectual life.
c. The considerations just mentioned may, indeed do, sometimes act as a handicap to the American student, for the simple reason that he comes later to the field of time. He must naturally defer to the decision of men in Europe who are supposedly familiar with original types. An American specimen is presumably the same as one occurring elsewhere in similar latitude and environment. It becomes evident after while that only in certain instances is this undoubtedly the fact. The flora of the American continent has been sufficiently disjoined in space and time from Europe to permit extensive differentiation even in these minor forms, so that we have indeed in the groups we study many species, some genera, definitely autochthonous, more it is believed than are now suspected. An attempt to bring a specimen under the terms of a species described in Western Europe is not seldom an error. It becomes evident, as we go forward, that in eastern North America there are forms not only not described in European literature, but really not, part of European flora, not even adventitiously.
d. Many of the more minute species with which this volume has to do are very elusive, very difficult; for one reason,—perhaps in itself sufficient,—because of their minuteness, and consequent apparent paucity. They may be common, but none the less seldom seen. The comatrichas afford an illustration. There are several very small species. C. pulchella, C. laxa, C. ellisii may be mentioned. C. pulchella has been studied nearly a hundred years and has a synonymy accordingly. In 1875 Rostafinski in the material, and among the descriptions, thought he recognized two distinct forms, and went on to give them names; the first in honor of Persoon, C. persoonii, should show an ovate or ovate-cylindric outline with acuminate tip; the second should be truncate and represent a type first described by Berkeley under a name given by Babington, C. pulchella. Berkeley's drawing shows a sporangium with tip acuminate! Lilac or violaceous tints attracted attention in the spores of C. persoonii only; in C. pulchella all is ferruginous. Curtis is especially commended for noticing the fact in describing S. tenerrima, here included as we see.
Comatricha gracilis Wing. is slender, cylindric and has small spores hardly reaching 6 µ; should perhaps be now set out as a separate species; it is evidently purely an American phase.
Our figures, [Plate XII]., 16 and 16 a, 18 and 18 a, show C. pulchella and C. gracilis, respectively, extremes. [Plate XIII]., 4, shows an ovate form not very unusual. This and C. gracilis occur on living leaves.
C. ellisii is another of this minor series, very constant in its delicate beauty, but approaches C. nigra rather than the others here discussed.
C. laxa, as the name implies, shows an open construction, suggested, perhaps, by Rostafinski's photographic print, but better brought out by Celakowsky, Myx. Böhm., Tab. 2, Figs. 7 and 8.
e. It has been shown[40] that the process of cell-division in the spore-plasm of the myxomycete is not dissimilar to that obtaining under the same conditions in higher plants. On this supposition we have explanation of spore-division in Ceratiomyxa and can understand the adherence of spores now and again notable. Once the latter phenomenon was thought peculiar to the genus Badhamia; but the unsculptured epispore of the spores of reticularias, tubiferas, etc., suggest the same thing and more recently we find it in Dianema and in the Stemoniteæ; even Stemonitis arrives with clustered spores in groups of four, and we are in sight of a generalization wide.
It is interesting to note that something of this sort was observed by at least one student long ago. Schumacher, Enum. Pl. Sell. 2, p. 215, describes Arcyria atra with the characters of an enerthenema, and says "the capillitial threads are some of them diffuse and bear spermatic globules"! Did he anticipate E. berkleyanum? See the text under that species at [p. 190], supra.