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The Barstow Formation, a deposit of alluvial-fan, fluvial, and lacustrine sediments 3,280 to 3,940 ft (1,000 to 1,200 m) thick, was deposited in the Barstow basin during Neogene time. The formation is well exposed in the Barstow syncline about 9 mi (14 km) north of Barstow. The palynomorphs of the Barstow End_Page 1696------------------------------ basin were probably deposited in a wide, but relatively small, body or bodies of fresh to slightly saline water with fluctuating shorelines. The basin formed on the northern extremity of the Barstow-Bristol trough. The most abundant palynomorphs found in the Barstow Formation belong to Asteraceae, Chenopodiaceae, Ephedra, Eriogonum, Pinus, and Quercus. Also present in lesser abundances are specimens belonging to Onagraceae, Ericaceae, Juglans, Alnus, Carya, Arbutus, Typha, and Platanus. The palynomorph assemblage is dominated by a lowland shrub community in association with an upland community of oak and pine. This association is indicative of a dry summer climate similar to, but probably wetter than, the present climate. A middle to late Miocene age has been assigned to a vertebrate mammalian fauna near the sample locality, and radiometric dates of 13.3 to 15.9 m.y.B.P. have been obtained from local tuff beds. The large relative abundances of Ambrosia, as well as the presence of Artemisia, indicate an age of early Pliocene for the Barstow Formation, based on present palynologic information. End_of_Article - Last_Page 1697

Southern California has its dry season in the summer, and comparatively few flowers are to be seen. Among those that remain, and are attractive to insects, the bushy species of Eriogonum are especially noteworthy, and I was fortunate in obtaining from them several bees.Eriogonum fasciulatum was determined for me by Mrs. K. Brandegee. The Mt. Lowe species, which look very distinct from fasciculatum, is kindly identified by Miss Susan G. Stokes as E. fasciculatum polifolium, “one of the intermediate forms.” This is the E. polifolium of Bentham.

THE region of the Pacific States with which the book under review deals is of great interest to the student of geographical distribution and the taxonomist. The area is peculiarly rich in endemic genera and species, and this is especially true of California. The Pacific States show interesting geographical connexions with the flora of Eastern Asia in genera, however, which are probably too recent in origin to be adduced in support of any hypothesis of continental drift, but are to be regarded rather as evidence of the similarity of ecological conditions and the high efficiency of dispersal agents, not perhaps excluding man himself. Thus the saxifragaceous species Leptarrhena pyrolifolia is native both to the coastal regions of north-west America and to eastern Asia. Again, the genus Pectiantia comprises five species of which three are endemic to the Pacific States, whereas the other two are natives of Japan. But it is in the endemics of the region that the chief interest of the flora rests. Some of these, such as Romneya Coulteri, the genera Eschscholtzia and Lewisia, are familiar to British horticulturists. In the family Polygonaceae the monotypic genera Gilmania, Nemacaulis and Hollisteria are all endemic to California while of the 150 known species of Eriogonum 80 are found in the Pacific States, many of them endemic. In the Crassulaceae there are some 35 endemic species belonging to the genera Sedella, Budleya, Stylophyllum, Hasseanthus and Gormania. In the Cruciferse most of the species of Thelypodium, Streptanthus and Caulanthus are endemic. The Rosacese, too, provide a large number of endemics, particularly in the genera Horskelia (19 spp.) and Ivesia (17 spp.). In the Leguminosse the outstanding genera in this respect are Lupinus, of which 58 species are probably endemic, Hosackia, of which most of the 39 species are endemic, while Astragalus is represented by 137 species of which 83 are probably endemic. Illustrated Flora of the Pacific States Washington, Oregon and California. By Leroy Abrams. In 4 vols. Vol. 2: Polygonaceae to Krameriaceae, Buckwheats to Kramerias. Pp. viii + 635. (Stanford University, Calif.: Stanford University Press; London: Oxford University Press, 1944.) 45s. 6d. net.

Three unnamed buckwheats listed by the United States Fish and Wildlife Service in December 1980 as potentially endangered or threatened plants are formally proposed:E. crosbyae from Lake Co., Oregon;E. grande var.dunklei from San Miguel Island, Santa Barbara Co., California; andE. ovalifolium var.williamsiae from Washoe Co., Nevada. Several other species proposed by the Fish and Wildlife Service as potentially endangered or threatened (E. allenii, E. correllii, E. eremicum, E. floridanum, E. lemmonii, E. sp./sp. nov. ined. [=E.libertini], E. tumulosum, E. umbellatum var./var. nov. ined.,E. umbellatum var.minus, E. vestitum, andE. zionis var.coccineum) are discussed and evidence is given why they cannot be considered endangered or threatened under the present Endangered Species Act of 1973, as amended.

The characteristics of the upper first internode of flowering stems of Eriogonum infla- tur have been regarded as indicators of varietal differences within the species: var. inflatum, with inflations; var. deflatum, without inflations. Inflations also have been claimed to be caused by galling insects. Studies on three populations in central and northwestern Arizona indicate that each individual passes through a stage without inflated stems before producing inflated stems, indicating that these varietal distinctions are invalid. Also, inflations developed without insect attack, and a population in northwestern Arizona has large inflations in the total absence of insect attack. Eriogonum inflatum Torr. et Frem., wild buckwheat or desert trumpet, is a common component of the native flora in many areas of the arid southwestern United States and northern Mexico. Occurring in the Mohave and Sonoran deserts and adjacent uplands, mostley below 1,200 m elevation, the scapose perennial has a basal rosette of leaves and branched flowering stems up to 1 m tall, with striking inflations found in the upper portion of the lowermost internode of many plants, and often in the second and third internodes of larger plants. There is some doubt about the validity of the varieties E. inflatum var. inflatum and deflatum Johnst. (Stokes, 1936; Stone and Mason, 1979), although a recent monograph treats them as biological realities (Reveal, 1976). While the literature generally has regarded the inflated stems as an intrinsic character of the species, Stone and Mason (1979) have argued that these stems are induced by insect attack and should be regarded as insect galls (caused by pyralid moth or mordellid beetle larvae). This study was initiated to attempt to understand the nature of inflations, partly because the arguments made by Stone and Mason (1979) were not com- pletely convincing: (1) In one population they reported that 97% of inflated stems showed insect damage(p. 78), but the question of why 3% should have inflated stems but no insect damage was not addressed. (2) The authors noted that in greenhouse studies neither seedlings nor transpanted stock developed inflations and concluded that in the absence of insects these did not develop (p. 79). The alternatve hypothesis that conditions in the greenhouse were not sufficiently favorable for development of inflated stems was not considered. (3) the authors observed that larger inflations usually contained larvae whereas smaller inflations were damaged but without larvae, concluding that the longer a larva was present the larger the inflation would become (p. 80). However, the alternative hypothesis was not evaluated that larvae select preformed inflations and remain in them according to the amount of food present. (4) The authors also argued that inflations on internodes above those attacked were induced by the larvae in the lower internode (p. 80-81). This would be a most unusual effect of a galling insect without an apparent adaptive value to the insect. (5) Stokes (1936) had suggested that the inflations failed to develop in extremely dry conditions, but this possibility was not examined by Stone and Mason (1979).

Two desert shrubs belonging toEriogonum subgen.Eucycla sect.Corymbosa are described from southern Utah and northern Arizona.Eriogonum mortonianum, endemic to red clay hills southwest of Fredonia, in extreme northeastern Mohave County, Arizona, is most closely related toE. smithii, a species endemic to the San Rafael Desert of Emery County, Utah, but differs in having wider leaves, a much more branched inflorescence, and smaller, pale-yellow or white flowers.Eriogonum leptocladon var.papiliunculi, found in central Garfield and eastern Kane counties, Utah, southward into northern Coconino and Navajo counties, Arizona, is distinguished from var.leptocladon by its white flowers and from var.ramosissimum by its glabrous stems.

Five new entities ofEriogonum are described from Baja California and Baja California Sur, Mexico, including one species,E. preclarum, and four varieties of other species:E. fasciculatum var.emphereium,E. wrightii var.oresbium,E. elongatum var.areorivum, andE. grande var.testudinum. Three combinations are proposed:E. wrightii var.dentatum,E. elongatum var.vollmeri, andE. repens.

This species complex is native to the desert regions of west-central North America having had its origin in northern Mexico. It consists of 9 species and 3 varieties. One species,Eriogonum moranii is described as new, and three new combinations,E. austrinum, E. deflexum var.turbinatum, andE. deflexum var.baratum are proposed. A history of the complex, along with a discussion of the ecological and phytogeographical nature of each taxon, is presented. Chromosome numbers are reported, with all species counted having 2n = 40. A comprehensive key is included, followed by descriptions, short lists of exsiccatae, and discussions of relationships among the species.