NA TURK 



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THURSDAY, AUGUST 2Z> ^9^1- 



NEW BOOKS ON PLANTS. 

 (i) The Principles of Plant-Teratology. By W. C. 

 Worsdell. \'ol. ii. Pp. xvi -r 296 + pjates 26-53. 

 (London : The Ray Society, 1916.) Price 255. 

 net. 



(2) Plants Poisonous to Live Stock. Bv H. C. 

 Long. ("Cambridge Agricultural Monographs,") 

 Pp. vi+119. (Cambridge: At the University 

 Press, 1917.) Price 65. net. 



(3) Herbs Used in Medicine (First Series), tvith 

 Descriptive and .Explanatory Notes. By Mrs. 

 J. D. Ellis. Pp. 32. (London : National Herb- 

 growing Association, 1917.) .Price 35, 



(4) British ^Jlld Flozvers : Their Haunts and Asso- 

 ciations. By W. Graveson. Pp. xv 4- 320. (Lon- 

 don: Headley Bros.) Price js. 6d. net. 



(i) T X our notice of the first volume of Mr. 

 -»- Worsdell's " Principles of Plant Teratology" 

 (Natlre, February 22, 1917) reference was 

 made to the scop>e of the work and to the author's 

 views as to methods of morphological investiga- 

 tion. The second and final volume deals with the 

 flower of the vascular plants, the term " flower " 

 including not only the flower of Angiosperms, but 

 also the "cones " of Gymnosperms and vascular 

 cryptogams and the sporophylls of ferns. 



There are three main sections, entitled " Diff"eren- 

 tiation," "Simplification," and "Adventitious 

 Flowers." L'nder the first head are grouped the 

 following phenomena : Proliferation ; forking and 

 fasciation ; disruption, a term applied to the split- 

 ting of the maize-cob, a female inflorescence, into 

 the constituent branches which are normallv united 

 to form the cob; positive dedoublement, including 

 increase in number of the members of a w-horl 

 (polyphylly) and increase in number of the whorls 

 (pleiotaxy); dialysis, splitting or dissociation of 

 members ; and metamorphosis. Simplification in- 

 cludes abbreviation of the inflorescence and flower, 

 adnation of floral axes or floral leaves, cohesion 

 and suppression. Adventitious flowers are rare : a 

 few cases are cited, and the remarkable instance of 

 the Nepaul barley is described. 



Most of the phenomena described under Differen- 

 tiation are regarded as reversionary-, though a 

 number of those due to metamorphosis are recog- 

 nised as progressive. The flower is considered 

 as evolved from an elongated leafy shoot, the cone 

 forming an intermediate stage ; hence prolifera- 

 tion, which involves an elongation of the axis 

 beyond the normal, is a reversionarv process. On 

 the other hand, granting that " siniplification " of 

 the flower by means of cohesion and suppression 

 of its members represents one of the main pro- 

 cesses of floral evolution, teratological phenomena 

 of cohesion and suppression are regarded as pro- 

 gressive in nature, while those Involving dissocia- 

 tion are reversionarv. The splitting to a greater 

 Or less deeree of the corolla of. a gamopetalous 

 flower into its component petals Is not unusual, 

 as. for instance, in Campanula ; this is a case of 

 NO. 2495, VOL. 99] 



reversion, because the flower with united petals 

 represents a higher state of evolution than the 

 flower with free petals. On the other hand, the 

 reverse phenomenon of union of petals which are 

 normally distinct is progressive. But does it 

 represent anything more than mere terminology 

 to call one of these instances progressive and the 

 other reversionary? And is there any reality in 

 the suggested relationships.^ 



The study of plant abnormalities is full of 

 variety and interest, and rich in surprises ; to 

 have prepared a book of reference on the sub- 

 ject is to have earned the gratitude of one's fellow- 

 botanists. But Mr. \\'orsdeirs work would have 

 claimed a higher position if fewer pages had been 

 devoted to theorising; the role of the recorder is 

 an eminently useful one. 



(2) Mr. Long's book on plants poisonous to 

 live stock in the L'nited Kingdom forms a handy 

 work of reference In a subject on which the litera- 

 ture is remarkably scattered. The author has 

 brought together many facts from numerous 

 technical reports and journals, and the compila- 

 tion will be of great value to those responsible for 

 the Care and treatment of animals. The plants 

 included are more or less common wild plants which 

 might be eaten by grazing animals or be mixed 

 with fodder, but reference is also made to com- 

 mon ornamental plants known to be dangerous, 

 such as laburnum, rhododendron, and cherry 

 laurel ; and poisonous leguminous plants, such 

 as Indian peas (Lathyrus sativus), Java beans 

 (Phaseolus lunatus), and lupines, are described at 

 length. Excepting ergot, fungi are not included. 



Poisonous plants differ widely in degree of 

 harmfulness, and It Is probable that under ordinary 

 conditions many of the plants commonly regarded 

 as poisonous are almost or quite harmless. In 

 a state of nature animals appear to avoid toxic 

 or unwholesome plants and to be less readily 

 poisoned than are domesticated animals. Individu- 

 ality is also a factor, some animals having a 

 depraved appetite for unusual and unappetising 

 food plants. The author quotes a remark of two 

 American writers, that " there seems to be no way 

 of accounting for the appetite or taste of stock." 

 This statement is perhaps especially true of sheep, 

 which will eat greedily on one day plants which 

 they could scarcely be persuaded to eat on the 

 following day on the same range of hills. The 

 toxic properties of the plant are often affected 

 by conditions of soil, climate, and cultivation ; 

 for instance, Solanum nigrum, an almost cosmo- 

 politan weed, varies so much that it has been 

 regarded as harmless in one country and poisonous 

 in another. Again, a plant may be poisonous In 

 all Its parts, e.g. meadow saffron; or one part 

 alone mav be toxic, as the seeds In corn cockle. 

 Frequently, as with buttercups, there are varia- 

 tions in the poisonous character according to the 

 season, and some parts of the plant are more 

 toxic than others; the flowers are the most 

 poisonous, and then the leaves and stem. 



The plants are arranged In systematic sequence 

 under their respective families. Evidence for in- 



D D 



