Date of this Version
One-celled aquatic plants living in filaments, or more commonly broken into single cells ; free, attached to the substratum, epiphytic on other plants, or enclosed in gelatinous tubes ; cell wall of cellulose infiltrated with silica; the wall of each cell (frustule) consisting of two plates (valves) which form the ends of the cell and are connected by two or more girdles, the one fitting outside the other like the cover of a box. Protoplasm parietal and forming a large mass in the center of the cell in which the nucleus is located and which separates the central vacuole into two parts. Chromatophores plate-like or granular; chlorophyll obscured by a brownish coloring matter, phycoxanthin. In the elongated, free-swimming families, Naviculaceae, Bacillariaceae, and Surirellaceae, there is a longitudinal slit (raphe) which in Naviculaceae is median, or nearly so, and in the other families is lateral. Propagation by cell division in which each daughter cell retains one of the valves of the mother cell. Reproduction by the sexual or asexual formation of auxospores.
Many of the descriptions have been adapted from other works, but in all cases so modified as to include any peculiarities found in our local forms. The drawings are all original except that of Chaetoceros elmorei, this one being taken from the drawing accompanying the original description by Professor C. S. Boyer. The drawings are of actual specimens and in no case has an attempt been made to represent generalized or typical forms. In diatoms the same species occurs in many forms, hence the large number of figures given for some species. All of the localities where each species has been found are given. This forms a fair measure of the frequency of occurrence of any species.
The writer wishes to express his indebtedness to the late Professor C. E. Bessey and Professor E. H. Barbour, of the University of Nebraska, for advice and assistance in the work throughout; also to Professor C. S. Boyer, of Philadelphia, for the identification of several species as well as for many valuable suggestions. The work of Mrs. Eleanor Barbour Cook on a particularly rich deposit of diatomite at Agate, Nebraska, has been incorporated into this work, all of the species reported from Agate being from this collection and from one sent by Mr. Harold J. Cook.
The fossil material from Greeley County was collected in 1887 by Mr. Russell and given to Professor Bessey, who furnished it to the writer. That from other localities was furnished by Professor Barbour, some of it having been collected by Mr. A. C. Whitford, that from Thedford by Mr. J. N. Neely and Mr. J. M. McMillan, and that from Merriman by Mr. L. E. Fagan. The collection from Loup City was furnished by Mr. Clarence 0. Peterson, and that from Hay Springs by Prof. R. W. Ellis.
Much of the recent material has been collected by friends of the writer, among whom are: Prof. W. E. Allen, Fresno and Stockton, Calif.; Rev. J. M. Bates, Atkinson, Ewing, Long Pine, and Red Cloud ; Prof. A. T. Bell, Crete; Prof. C. E. Bessey, Ashland ; Miss Grace Bradburn (Mrs. Chas. Frisch), Broken Bow; Miss Pearl Chase, Ainsworth ; Prof. F. E. Clements, Holt County; Miss Alba Cosner, New Helena; Miss Harriet Ege, Rosebud, S. Dak. ; Miss Cora Elmore (Mrs. C. H. Bancroft), Talmage; Mr. Wm. Fleming, Cheyenne, Wyo.; Prof. J. H. Flodman, Wahoo; Miss Ethel Hansen, Grand Island; Mr. W. J. Hesser, Plattsmouth; Miss Isabel Johnston, Lodi ; Mr. Ray Kellenbarger, Anselmo ; Mr. E. F. Lange, Fairbury; Mr. Ray McCann, Estes Park, Colorado; Mr. Theodore Moline, Polk; Prof. A. K. Peiterson, Weeping Water; Prof. N. F. Petersen, many places in eastern Nebraska; Prof. Roscoe Pound, Sheridan County, Cherry County; Prof. J. H. Powers, Colorado; Prof. A. A. Reed, Crete; Mr. 1. A. Reed, Blue Springs; Rlrs. Perry Robbins, New Helena; Mr. Windom Rosene, Stromsburg; Prof. DeAlton Saunders, Bellevue; Miss Laura Sutherland. Chippewa Falls, Wis. ; Miss Lil'an Sutherland. Pawnee City; Miss Fae Troyer (Mrs. Wm. Fleming), Turtle River and Dallas, S. Dak.; Prof. J. E. Weaver, Crete; A. C. Whitford, Dismal River and many other places in the Sand Hills; Prof. Elda R. Walker, lakes in Sand Hills; Prof. R. T. Young, Devils Lake, N. Dak. Besides these much material from the vicinity of Grand Island has been furnished by members of the writer's own family.