Family Elaeagnaceae.

39. Lepargyraea argentea (Pursh) Greene, Pittonia 2:122 (1890). This small tree was first named Elaeagnus argentea by Nuttall in Fraser's Catalogue in 1813; but this being a name only, with no description whatever, it cannot be considered valid. In 1814 Pursh in his Flora Americae Septentrionalis, 1:115, described it as Hippophae argentea, giving no credit whatever to Nuttall for the specific name. In 1817 Rafinesque, in the American Monthly Magazine, separated it and erected the genus Lepargyraea, and about a year later Nuttall independently erected the genus Shepherdia (Genera of North American Plants, 2:240, 1818). Nuttall's name was generally accepted and is still used in Gray's and Coulter's Manuals.

SUB-ORDER SAPINDALES. Family Sapindaceae.

40. Aesculus glabra Willdenow, Enumeratio Plantarum Horti Regii Botanici Berolinensis, 405 (1809).

41. Acer glabrum Torrey, Annals of the Lyceum of New York, 2:172 (1826).

42. Acer saccharinum L. Sp. Pl. 1055 (1753). This tree is commonly given the name A. dasycarpum Ehrhart, Beitraege zur Naturkunde, 4:24 (1789), but the name given by Linne certainly belongs to this tree, since the specimens in his herbarium with this name attached, as well as the original description, agree fully with our tree. Dr. Gray long ago (1839), in a letter to Dr. Torrey (Letters of Asa Gray, 1:150), called his attention to the fact that Linne referred to the tree subsequently described by Michaux (Flor. Bor.-Am., 2:253, 1803) as A. eriocarpum, which is identical with Ehrhart's A. dasycarpum. For some reason, not now regarded as valid, no effort was made to restore this name, and so we find that in all the editions of Gray's Manual, down to the present, the error has been permitted to stand.

43. Acer barbatum Michaux, Flora Boreali-Americana, 2:252 (1803). There has been much confusion as to the names of

this and the preceding species. It appears that this tree was not separated from the preceding species for half a century after Linne had bestowed the name A. saccharinum upon one of our sugar-producing maples. Wangenheim in 1787 (Beytrag zur teutschen holzgerechten Forstwissenschaft die Anpflanzung Nordamericanischer Holzarten, page 26), supposing that Linne's description referred to the maple from which most of the sugar is made, described and figured it under the name A. saccharinum. Thus we have had two trees bearing the same name. In 1803 Michaux described this as distinct from A. saccharinum, and his name is therefore the earliest available one. In Gray's Manual this is still given the name A. saccharinum.

44. Acer negundo L. Sp. Pl. 1056 (1753). This is the Negundo aceroides Moench (Methodus Plantas Horti Botanici et Agri Marburgensis, 1794), and this name has been generally adopted in American manuals. In Gray's and Coulter's Manuals this name is used. In some lists the name appears as Negundo negundo (L.) Sudworth, while in still others, as Rulac negundo (L.) Hitchcock. Since, however, this tree is really a maple, there is no good reason for abandoning the name originally given by Linne.

Family Anacardiaceae.

45. Rhus copallina L. Sp. Pl. 266 (1753).

Family Juglandaceae.

46. Juglans cinerea L. Sp. Pl., ed. 2, 1415 (1763).

47. Juglans nigra L. Sp. Pl. 997 (1753).

48. Hicoria ovata (Mill.) Britton, Bulletin of the Torrey Botanical Club, 15:283 (1888). This was first called Juglans ovata by Miller in the Gardener's Dictionary, edition 8 (1768). In 1808 Rafinesque separated the hickories generically from the walnuts under the name Hicoria (by a typographical error printed "Scoria"), but Nuttall, in ignorance of this, made a genus with the same limitations, but with the name Carya

(Genera of North American Plants, 2:220, 1818). Nuttall's name was taken up by botanists generally, that of Rafinesque being allowed to remain in obscurity until it was revived by Britton in 1888. Through a mistake by Michaux (Flora Boreali-Americana, 2:193, 1803) this was called by him Juglans alba, but it is not the J. alba of Linne (Sp. Pl. 997, 1753). Nuttall transferred this mistake, calling this tree Carya alba, the name by which it has generally been known. In Gray's Manual, even in the latest edition, Nuttall's name is used.

49. Hicoria laciniosa (Michaux) Sargent, Silva of North America, VII., 157 (1895). This is the H. sulcata (Nutt.) Britton of previous lists, and is the Carya sulcata of Gray's Manual. 50. Hicoria alba (L.) Britton, Bulletin of the Torrey Botanical Club, 15:283 (1888). This is the Carya tomentosa of Gray's • Manual.

51. Hicoria glabra (Mill.) Britton, Bulletin of the Torrey Botanical Club, 15:283 (1888). This is the Carya porcina of Gray's Manual.

52. Hicoria minima (Marshall) Britton, Bulletin of the Torrey Botanical Club, 15:283 (1888). This is the Carya amara of Gray's Manual.

Family Cupuliferae.

53. Quercus alba L. Sp. Pl. 996 (1753).

54. Quercus minor (Marshall) Sargent, Garden and Forest, II., 471 (1889).

55. Quercus macrocarpa Michaux, Histoire des Chenes de l'Amerique, 2 (1801).

56. Quercus acuminata (Michx.) Sargent, Garden and Forest, VIII., 93 (1895). This is the Q. prinus, var. acuminata of the fifth edition of Gray's Manual, and the Q. muhlenbergii of the sixth edition. This last name was used in the later lists issued by the botanical department of the University.

57. Quercus prinoides Willdenow, Neue Schrift. Gesell. Nat. Fr.

Berlin, 3:397 (1801). In the fifth edition of Gray's Manual this bore the name of Q. prinus, var. humilis.

58. Quercus rubra L. Sp. Pl. 996 (1753).

59. Quercus coccinea Muenchhausen, Der Hausvater, V.,254 (1770). This species has commonly been attributed to Wangenheim (1787), but Muenchhausen antedates him by seventeen years. 60. Quercus velutina Lamarck, Dictionnaire de Botanique, 721 (1783). This is the Q. discolor of Aiton (1789), the Q. tinctoria of Michaux (1803), and the Q.coccinea tinctoria of De Candolle (1864), which name it still bears in Gray's Manual. 61. Quercus marilandica Muenchhausen, Der Hausvater, V: 253 (1770). By a mistake in determination Wangenheim described this tree (1781) under the name Q. nigra, which Linne had applied to another tree, an error which has been continued to the present, still occurring in the latest edition of Gray's Manual.

Michaux, Histoire des Chenes de

62. Quercus imbricaria Michaux,

l'Amerique, 9 (1801).

63. Ostrya virginiana (Miller) Willdenow, Species Plantarum, 4:469 (1805).

64. Carpinus caroliniana Walter, Flora Caroliniana, 236 (1788). This is the C. americana of the fifth edition of Gray's Manual, and the C. virginiana of some previous lists.

65. Betula papyrifera Marshall, Arbustum Americanum, 19 (1785). 66. Betula occidentalis Hooker, Flora Boreali-Americana, 2:155 (1839).

67. Betula nigra L. Sp. Pl. 982 (1753).

A COMPARISON OF FOSSIL DIATOMS FROM NEBRASKA WITH SIMILAR DEPOSITS AT ST. JOSEPH, MO., AND AT DENVER, COLO.

C. J. ELMORE.

About a year ago Professor Barbour furnished me some diatomaceous earth from various deposits in Nebraska, and the results of my study on them were brought before this Academy at its last meeting. These deposits were located in Wheeler county, Greeley county, at Thedford, and at Mullen. From the same source I recently obtained material from a deposit at St. Joseph, Mo., and one at Denver, Colo.

The diatoms from the two latter deposits show a striking similarity to each other, and all of the species in both are represented in Nebraska deposits.

The deposit at St. Joseph differs from any Nebraska deposit in being made up of comparatively few species. In all of the material examined only fifteen species were found; and of these, three composed the bulk of the deposit, the others being of infrequent occurrence. These three species are Cymbella cymbiformis (Kuetz.) Breb., Cystopleura turgida (Ehr.) Kuntze, and Cymbella gastroides Kuetz.

The following is a list of the species found:

Cocconeis placentula Ehr. Rather common, but not forming any considerable part of the deposit. Occurs about as frequently as in Nebraska deposits.

Cymatopleura elliptica (Breb.) W. Sm. Rare; only one specimen found. Also very rare in Nebraska deposits, being found only at Mullen, and only a single fragment there.

Cymbella cymbiformis (Kuetz.) Breb. Forms a considerable por