DECEsrBEK 6, 1895.] 



SCIENCE. 



775 



which comprises the greater part of the edible 

 portion of the pome, as the receptacle, whilst 

 Americans have been taught by Gray and others 

 that this cup is a calyx-tube. This ilower-cup 

 of the drupaceous roseworts ' is the axis or re- 

 ceptacle of the flower which assumes this re- 

 markable form. The hollowing out of the re- 

 ceptacle brings the points of origin of the calyx, 

 petals and stamens above the ovary.' (P. 170.) 

 The stamens are therefore borne upon the edge 

 of the hollow receptacle rather than upon the 

 throat of the calyx, as we have been taught, and 

 this receptacle is deciduous in the drupes ! It is 

 generally held that the very proof of being a re- 

 ceptacle is the fact that it persists and bears the 

 ripened fruit. If this cup-ring which falls off 

 the drupe-fruit is really a receptacle, then it is 

 difficult to explain the structure of the rubus 

 flowers upon the same plan, for in them the 

 stamens are clearly borne upon the calyx-rim, 

 and the receptacle persists within the multiple 

 ' fruit. ' The only warrant for calling this 

 flower-cup a receptacle is found in the rose-hip ; 

 but this organ proves itself a receptacle hecause 

 it persists and because it bears the fruitlets scat- 

 tered upon its interior. But the outside cover- 

 ing of the hip is, if analogies with other genera 

 are true, a calyx-tube covering ; and in some 

 roses this calyx covering is almost free from the 

 receptacle. It seems to be easy to demonstrate 

 that the flesh outside the carpels or core in the 

 pomes is thickened calyx, and not receptacle ; 

 for the carpels all spring directly from the apex 

 of the pedicel (and not from an expanded and 

 cup-like surface, as in the rose-hip), and the 

 sepal tips still persist in the ripened ' fruit. ' If 

 the flower-cup in the roseworts is a calyx-tube, 

 then the structure of the flower is fairly uniform 

 in principle throughout the family ; but if it is a 

 receptacle in prunus and pyrus, then a different 

 architecture of flower must be assumed for all the 

 rubus-like, fragaria-like and spirsea-like plants. 

 L. H. Bailey. 



An Introduction to the Study of Seaweeds. By 

 George Murray, F. R. S. E., F. L. S., etc.. 

 Keeper of the Department of Botany, British 

 Museum. London and New York, Macmillan 

 & Co. 8vo. Cloth, 271 pp. 8 colored plates 

 and 88 illustrations in the text. $1.75. 



The algse are least well treated of all the 

 groups of plants in the average text-book, al- 

 though for purposes of morphological com- 

 parison and general phylogenetic considera- 

 tion they are of the first importance. The 

 author of this most valuable and welcome lit- 

 tle book has shown such familiarity with his sub- 

 ject, and such appreciation of the relative im- 

 portance of detail, that it is much to be re- 

 gretted that he has confined himself to the 

 marine members and has not treated the group 

 as a whole. 



The author has modestly entitled his book, 

 'An Introduction to the Study of Seaweeds,' 

 but we may venture to predict that it will be 

 used rather as a handbook both by the less ad- 

 vanced and by the more advanced student, 

 combining, as it does, summaries and discussions 

 of the very latest literature and personal re- 

 searches with such convenience of form and 

 simplicity of style of writing that it is not only 

 valuable to the special student but available 

 also to the general reader. 



Mr. Murray, after a general introduction 

 treating of the important topics concerning the 

 seaweeds in general and the division of the 

 group into the four ordinary subgroups fairly 

 well characterized by their color, begins for 

 purposes of convenience with the Olive-green 

 or Brown Seaweeds. Starting with the more 

 complicated forms of these, the rock-weeds and 

 gulf-weeds or Sargassa, he proceeds to the less 

 complicated forms, tracing the simplifications 

 of structure and details of reproduction, step 

 by step down to the lowest forms of the group. 

 It is noticeable, however, that the simplest un- 

 doubted member of the group, the Phasosaccion 

 Collinsii, described by Farlow from our New 

 England coast, and by Rosenvinge from the 

 Greenland coast, is omitted, whether purposely 

 or not is not evident. It is, however, a form so 

 different in its cylindrical thallus of a single 

 layer of cells, without hairs and without special- 

 ized zoosporangia, that a discussion of its rela- 

 tionship with Punctaria, for example, would have 

 been of very considerable interest. 



The Grass-green Seaweeds follow the Olive- 

 green, and while admirably treated are perhaps 

 less interesting than the latter. It is interesting 

 to note that Codiolum is removed from beside 



