544 TRANS. ST. LOUIS ACAD. SCIENCE. 



ferences are marked in some species, more diflerentiation also 

 occurs in the minute structure. To what extent this ma}' be used 

 in the determination of the species, will be seen from the descrip- 

 tion of the species themselves. 



It has been claimed that the minute structure of many seeds is 

 so characteristic that a study in this direction would greatly 

 aid in the discrimination between related species. Artificial 

 classifications on this basis are very useful so far as they go. 

 They may be used with advantage in the separation of important 

 Orders, as Harz^ and others have shown. A knowledge of the 

 structure of seeds has enabled botanists in many cases to detect 

 the adulterations of various agricultural and garden seeds, and 

 the impurities of drugs and articles of food, and artificial clas- 

 sifications will enable one, with some precision, to locate the 

 Order of the plant from which the impurity has been derived. 



Considerable work has been done by various botanists in work- 

 ing out the structure of the seed-coats of many Orders, so that 

 the question whether the seed-coats offer microscopic characters 

 sufficiently distinct to separate species can now be answered very 

 satisfactorily. The Order Leguminoste more than any other 

 has been studied with a view to determine the interesting points 

 about the structure of the seeds, especially the Malpighian cells, ^ 

 which are nearly always present. I have examined the seeds of a 

 large number of North American and other genera ; the Malpi- 

 ghian cells are present in all of the genera with the exception of 

 Arachis. In this genus the light line is absent and the cells are 

 not much longer than broad. Different genera show, of course, 

 great difference in the length of these cells. This would naturally 

 depend on the size of the seed itself. The cells of the second layer 

 show greater variation. 



H. Godfrin,* who wished to determine the systematic value of 

 seed-coats, has given us the results of his investigation. He exam- 



2. Harz : Landwirthschaftliche Samenkunde, 2 vols., Paul Parey, i8Ss, vol. ii. p. 555. 



3. O. Mattirola (La linea lucida nelle cellule malpighiani degli integumenti seminali. — 

 Mem. della R. Ace. delle Sci. di Torino, Ser. ii., vol. xxxvii.)— Sella (Just. Bot. Jahreshe- 

 richt, :SSs, p. 825), calls attention to the fact that Targioni Tozzetti, in 1S54, named these 

 •' Malpighian cells." (Saggio di studi intorno al gascio dei Semi., Torino, 1S54.) They 

 should therefore bear the name of Malpighi, who first observed them. 



4. Etude histologique sur les teguments seminaux des angiosperms, Nancy, :SSo, pp. 

 U3, S Plates. A, Peter, Just. Bot. Jahresbericht iSSo, p. 137. 



