186 



SCIENCE 



[N. S. Vol. XXXIV. No. 867 



southern California, and the following zones 

 are recognized, according to the classification 

 of 0. Hart Merriam: Sonoran, Transition, 

 Canadian, Hudsonian and Boreal. A useful 

 census of California trees is given where the 

 species are not only arranged according to 

 families, but the occurrence of each in the 

 several previously mentioned phyto-geo- 

 graphic provinces is given. Jepson recog- 

 nizes the difficulty of always deciding as to 

 whether a species is a tree or a shrub by a 

 brief account of the arboreous forms of 

 shrubs, such as Prunus demissa, Alnus tenui- 

 folia, toyon E eteromeles arhutifolia, etc. A 

 list of the typically Californian species is 

 added. Perhaps to the ecologist, the most in- 

 teresting part of the memoir is the one de- 

 voted to the dendrologic characters of Cali- 

 fornia trees. These are considered under the 

 captions, mutilation and regeneration, seed 

 production, architectural forms, wind-con- 

 trolled tree forms, weeping trees, vanism in 

 endemic species, natural hybrids, the " wal- 

 nut-oak hybrids," teratology, leaf persistence, 

 age of California trees and a bibliography 

 with consideration of nomenclature. 



After a syiropsis of families, the author 

 proceeds to minutely describe the characters, 

 botanic habitat and history of each tree 

 found in the Californian region and these full 

 descriptions are supplemented by the plates 

 of trees in the forest, as well as numerous 

 plate figures illustrating the botanic charac- 

 ters of each tree admitted into the volum.e, as 

 occurring within the confines of the state. 

 Two maps illustrate the geographic distribu- 

 tion of the big trees (Sequoia gigantea) and 

 a third is a general map of California show- 

 ing the mountain chains, valleys and river 

 systems of most importance to phytogeog- 

 raphy. To make the work completely rounded, 

 a subject index and a geographic index con- 

 clude the memoir. Altogether in a most 

 thorough manner. Professor Jepson leaves 

 little for the future botanist to consider from 

 the purely systematic standpoint. The vol- 

 ume ably supplements the account of the 

 California trees given in Sargent's " Silva," 

 in Ludworth's " Forest Trees of the Pacific 



Slope " and in Britton and Shaf er's " North 

 American Trees." 



John W. Haeshberger 

 University of Pennsylvania 



Hawaii and Us Volcanoes. By Charles H. 

 Hitchcock, LL.D., Emeritus Professor of 

 Geology in Dartmouth College. Pp. viii -f- 

 314; 52 plates. Honolulu, The Hawaiian 

 Gazette Co., Ltd. 1909. Second edition, 

 with supplement of 8 pages, 1911. 

 The Hawaiian Islands have long attracted 

 the attention of vulcanologists because no- 

 where else in the world can basaltic volcanoes 

 of such majestic proportions be so easily 

 studied as to both past history and the phe- 

 nomena of active eruption. While but two 

 centers can be described as now active, there 

 are many others where erosion has revealed 

 details of internal structure and petrographic 

 constitution. 



It is but natural that with nearly all ex- 

 plorers of the islands the liveliest interest has 

 attached to Mauna Loa and Kilauea, where 

 the spectacular phenomena of basaltic erup- 

 tions are displayed every few years and may 

 be observed with ease and safety. Owing to 

 the frequency of these eruptions during the 

 last hundred years there is quite an extensive 

 literature recording the observations of dif- 

 ferent outbursts, by geologists or laymen. 



Kilauea in particular presents such an un- 

 rivalled opportunity for the study of the 

 working of a basaltic volcano that several 

 writers have given much space to recording 

 its observed changes in historic times. 

 Dana's well-known " Characteristics of Vol- 

 canoes " devotes nearly two thirds of its space 

 to Kilauea and Mauna Loa, giving with con- 

 siderable detail the recorded history of these 

 volcanoes. Dutton, in his Geological Survey 

 report on the Hawaiian Islands,' also quotes 

 extensively from the published records of the 

 principal eruptions of the active volcanoes. 



It is clearly desirable that the eruptive his- 

 tory of Kilauea and Mauna Loa should be 

 made as complete as possible, so that the 

 student of present and future conditions at 

 1 Fourth Ann. Kept. U. S. Geol. Survey, 1882-3. 



