346 hackel's andropogone^. 



It is noteworthy that the whole thirty genera occur in the Old 

 World— only nine in the New. One-fourth of the species occur in 

 the New World, and, of these, seventy belong to the genus Anclro- 

 pofjcn. Of the total 425 species, twenty-eight occur both in the Old 

 and New World— in the main forming a connection between Tropical 

 Africa and Equatorial America. The AndropogonecB are thoroughly 

 tropical ; it is true that a dozen species extend to Europe, two or 

 three to Canada, one to Amurland, while on the other limit a few 

 occur at the Cape and in Argentina ; but the whole strength of the 

 tribe, in number of individuals as well as of species, is found in the 

 Tropics and below 5000 ft. altitude. 



In the definition of the five subtribes of Androimgonea;., and of 

 their genera, Hackel lays stress on nearly the same characters as 

 Bentham, i.e., principally on the inflorescence ; he finds, however, 

 that, in the frequent case of paired spiculae, one sessile fertile, the 

 other pedicelled imperfect, it is a character of small import whether 

 the pedicelled spicula be male, sterile, rudimentary, or obsolete. 

 On the other hand, he finds without exception that the subtribe 

 Isch(imc(B are separated from the subtribe Eu-Androjwgonea by 

 having the sessile spicuhie 2-flowered, i.e., having the lower flower 

 always male, whereas in the subtribe Eu-Andropof/onecE, the third 

 glume (representing the lower flower) never contains stamens. 

 This is the more remarkable, as in the Panicums, in one and the 

 same species, the lower flower often varies, male or sterile. 



We have lately heard a good deal of the emx^loyment of ana- 

 tomical characters in systematic work, and we have seen some very 

 crude attempts by anatomists to reconstruct a whole suborder on 

 one anatomical character alone : what should be aimed at is to give 

 the cellular arrangement seen in a cross-section of the stem its due 

 weight (and no more) in the sum of characters which determine the 

 systematic position of the plant. In the AndropogonecB, Hackel has 

 repeated and extended Kling's investigation into the anatomy of the 

 roots ; he has also examined cross-sections of the leaves of 100 

 species, and he finds in each case the results of no practical use for 

 systematic purposes. 



In describing the spiculae of grasses, Hackel follows the new 

 terminology adopted by Bentham, and not the old terms which 

 were accurate enough for R. Brown, Trinius, and Kunth. Herr 

 Hackel gives his reasons at pp. 21 and 22 of his Introduction. He 

 explains that the 8rd glume (reckoning from the base of the spicula 

 in the AndropogonecB) is a deckspelze (bract) homologous with the 

 lower empty glumes, and is, therefore, called Gluma III. through- 

 out the book. It may sometimes contain a male flower, or often 

 may be empty (or contain a pale only) ; the next glume above, 

 Gluma IV., contains a perfect or female flower. It is therefore 

 very wrong to call Gluma III. and Gluma IV. lower pales, as has 

 heretofore been the custom ; it is worse to treat them as parts of 

 the flowers ; and yet more wrong to call Gluma III. a sterile or 

 tabescent flower in those cases where no trace of a flower is in 

 its axil. 



So far our author. But something may be said in defence of 



