62 



NATURE 



[November tq, 1908 



de la region montasnei-ise, mais I'observeur ne s'en 

 trouve que plus rapproche de la liniite des neigcs 

 ^ternelles." 



The French is a correct translation of the German. 



The pith of this volume might have been summed 

 up in a single chapter without losing any important 

 contribution to science, and the space so saved might 

 have been devoted to a much-needed bibliography of 

 the subject. The author would not then have com- 

 pletely overlooked the work of the French explorers 

 in \'un-nan. The artistic excellence of the numerous 

 maps by which the volume is illustrated deserves 

 unciualified praise. 



FLOWERS A.\n WHIT THEY TEACH. 

 Types of Floral MccJniiii.^iu. A Selection of Diagrams 

 and Descriptions of Common Flowers. Arranged as 

 an Introduction to the .Study of Angiospernis. By 

 Dr. A. H. Church, Part i., Types i.-xii. (January 

 to .April). Pp. vii + 2n; with 52 full-page 

 plates (39 coloured) of floral structure, and 

 79 text-figures. (Oxford : Clarendon Press, 1908.) 

 Price 21.';. net. 

 T^HE title conveys a very imperfect idea of the 

 -L nature of this work, which stands apart from 

 all others that have been issued as introductions to 

 the study of botany. The method of teaching botany 

 by a careful investigation of selected types is, in- 

 deed, well known and much employed; but it lias 

 never been carried out, in English works at least, willi 

 any approach to the thoroughness of study of the 

 types in themselves and in their relations to their 

 environment and to their allies that we find here. 



The author in a preface informs us that the ad- 

 mirable illustrations were originally prepared for class 

 purposes, limited to a hundred types, of which twelve 

 " Early Spring Types " are included in the present 

 volume, and the arrangement and gener.-il scheme are 

 designed to represent the working method applicable 

 to the subject. 



" No methods are indicated, nor have anv been em- 

 ployed in making preparations which are "bevond the 

 reach of the ' elementary student ' ; and at the same 

 time a general ' elementary ' acquaintance with the 

 subject on the part of the reader has been assumed. 

 Since it is necessary to draw the line somewhere . . . 

 and the present work is admittedlv of onlv a general 

 and elementary character, histological details are 

 omitted." 



The twelve types treated of are, successively, Helle- 

 borus niger, Galanthus nivalis, Jasminum niidiflorum, 

 Crocus vernits, Richanlia ajricana, Daphne Mczc- 

 reinn, Viola odorata, A'arcisstis Pseiido-nariissiis, 

 Erica carnea, Rihes sangiiineum , Cydoiila japoiiica, 

 and ]'iiica major. 



In the study of such a series, it is evident that 

 there can be no close connection traced by an " ele- 

 mentary student " between so different types. Thus 

 each becomes the subject of a separate monograph. 

 That on Viola odorata may be taken as an example. 

 A brief general notice of its appearance, habitats, 

 tendency to vary, ;tnd production ot cleistogamic 

 flowers is accompanied by footnotes with references 

 NO. 2038, VOL. 79] 



to descriptions and figures by Dioscorides, Biunfels, 

 Gerarde, and other early botanists, and to its nanies 

 and cultivation in England. Then follow a detailed 

 description of the inflorescence and flower, and a 

 brief notice of the effects of cultivation on the flower. 

 The floral diagram and phyllota-^is are fully discussed 

 and illustrated, as are also the development of the 

 floral members and the " special mechanism " of the 

 flower for securing the reproduction of the species, 

 including the relations with various bees. The cleisto- 

 gamic flowers and the possible origin of this type of 

 flower are then treated of. 



The various floral " monstrosities " are enumer- 

 ated, and are " referred to failures in the adjustment 

 of certain features of the floral construction or 

 mechanism." The development and structure of the 

 capsules, their mode of opening, and the structure 

 of the seeds conclude the discussion under 1'. odorata. 

 Then follows a " Comparison of Allied Forms," under 

 which six and a half pages are devoted to Viola tri- 

 color, chiefly var. arveiisis, and five pages to V. 

 altaica, or " the garden pansy." For each of these 

 a detailed comparison of the structure and mechanism 

 of the several parts brings into view their resem- 

 blances and differences, and their relations with their 

 environment, .\lthough reference is made to the 

 " very variable " F. tricolor, there is little stress laid 

 on the extent of the tendency to vary, ;md the opinion 

 is expressed, even with regard to the relations between 

 r. tricolor, I', liitea, and allied alpine forms, that 

 " no sli.-.rp line of demarcation either exists or need 

 be drawn between ' specific forms ' which only exist 

 as useful conventions." While there is a risk of 

 attaching too high a value to the many forms that 

 have been distinguished and named by critical botan- 

 ists in the genus Viola, as in a good many other 

 genera, it may be questioned whether the author 

 might not have usefully directed the attention of 

 students to the nature and degrees oi constancy of 

 the forms so freely met with in the Linnean T'. 

 tricolor. 



The study of the types selected is employed by 

 Dr. Church as .1 basis for certain " Theoretical Con- 

 clusions " with regard to the origin and development 

 of the genus Viola. The hypothesis is expressed that 

 V. odorata is a " highly specialised representative of a 

 shrubby, or even arboreal, plant-phylum," with 

 " panicles of regular flowers, whicfi had already 

 passed from an asymmetrical vegetative type of con- 

 struction to a symmetrical pentamerous condition." 

 From this a later evolution led to structural eccen- 

 tricity of two phases, and to adaptations of the floral 

 mechanism for visits of certain insects. These con- 

 clusions find support from a study of the genera asso- 

 ciated in the family Violaceae, Viola standing out " as 

 the crowning genus of the entire group ; the type, 

 that is to say, in which the various modifications of 

 the original construction are present in the greatest 

 number, and combined to make a most efficient form 

 of floral mechanism." The relations of the forms 

 included under the family to types in other families 

 are discussed, and the steps are summarised that led 

 to the definition of the Violaceae as a family. 



•I 



