432 



SCIENCE 



[N. S. Vol. XXVII. No. ( 



occasional synonyms), the natural family, the 

 several vernacular names, the distribution, 

 properties of the wood, uses and structure. 

 Sixty-eight kinds are described in this way, 

 and these represent somewhat more than 

 eighty species. For the most part these be- 

 long to families and genera but little known 

 to the botanists of temperate climates, as 

 Pithecolohium, Parkia, Intsia, Pterocarpus, 

 Sindora and Pahudia of the Leguminosae; 

 Euphoria and Pometia of Sapindaceae; Koor- 

 dersiodendron and Buchanania of Aimcardi- 

 aceaej Sarcocephalus and Nauclea of Buhi- 

 aceae; and such unfamiliar families as 

 Dipterocarpaceae, Oombreaceae and Flacour- 

 tiaceae. 



The list enumerates dicotyledonous woods 

 only, although the palms, bamboos and screw- 

 pines yield poles, posts and other materials for 

 structural work. Of the conifers, while sev- 

 eral species are natives of the islands, they are 

 so scattered or they occur in such inaccessible 

 places in the mountains that they are prac- 

 tically unknown in the markets. 



An interesting discussion is given of growth- 

 rings, and we learn that they " seem to be 

 characteristic of some of our woods only." 

 " It also appears that many trees exhibit rings 

 of seasonal growth when they are young, but 

 not afterwards." We are told that a series of 

 observations on the manner and rate of forma- 

 tion of growth-rings in tropical trees is now 

 under way. We can not speak in too high 

 praise of the kind of work done in the prepara- 

 tion of this paper. 



belonging to the Hymenolichenes. The Gas- 

 terolichenes, indicated on page 49, are with- 

 drawn on page 239, as the result of recent 

 investigations. Throughout the volume the 

 lichens are regarded as fungi in symbiosis 

 with algae, in accordance with the prevailing 

 views as to the nature of these organisms. 



The general plan of classification adopted 

 by Zahlbruckner, who wrote the systematic 

 part, is as follows: 



Subclass ASCOLICHENES, 



Order Pyrenocarpeae, with thirteen fami- 

 lies, from Moriolaceae to Verrucari- 

 aceae^ and Mycoporaceae. 

 Order Gymnocwrpeae, 



Suborder Coniocarpineae, with three fam- 

 ilies, from Caliciaceae to Sphdero- 

 phoraceae. 

 Suborder Graphidineae, with five fam- 

 ilies, from Arthoniaceae to Roccel- 

 laceae. 

 Suborder Cyclocarpineae, with twenty 

 families, among which are Lecidi- 

 aceae, Gladoniaceae, Collemataceae, 

 Peltigeraceae, Parmeliaceae, Usne- 

 aceae, Theloschistaceae, Physciaceae, 

 etc. 

 Subclass Hymenouchenes, 



with but one family of three genera — 

 Cora, Corella and Dictynema. 



A valuable feature of the work is the indi- 

 cation under each family and genus of the 

 nature of the particular algae (" gonidia ") 

 associated with the fungal symbiont. 



THE SYSTEMATIC BOTANY OF THE LICHENS 



Ten years ago Fiinfstiick began the volume 

 dealing with the lichens in Engler and 

 Prantl'S, " Natiirlichen Pflanzenf amilien," and 

 now we have the closing Lieferung with title- 

 page and index. Including the index the vol- 

 ume covers 250 pages, and when bound will 

 constitute one of the smaller books of the 

 series. The illustrations, of which there are 

 125, are of the high order of excellence which 

 we have come to expect in this publication. 



It is estimated that there are about 4,000 

 species of lichens, nearly all of which belong 

 to the subclass Ascolichews, only seventeen 



STILL MORE SPECIES OP CRATAEGUS 



That the description of additional forms of 

 Crataegus under the name of " species " has 

 not yet come to an end is shown quite em- 

 phatically by an article entitled " Crataegus 

 in Southern Michigan," by Professor Sargent, 

 in the Report of the Michigan Geological 

 Survey for the year 1906. Prom material 

 collected in two localities in the eastern part 

 of the state, and one in the western, fifty-five 

 species are described, twenty-five of which are 

 new to science. Eighteen of the remaining 

 thirty species are of recent separation by 

 Ashe, mostly from one locality. We are told 



