I40 BOTANICAL GAZETTE [febeuaey 



^ 



of extensive crosses between various races of Indian com. In almost every regard 

 the important early work of Correns on this species is confirmed, it being again 

 demonstrated that yellow endosperm is dominant over white, starchy over sugary, 

 blue aleurone layer over white, and red pericarp over white. The latter being a 

 character of the mother plant does not appear as "xenia." The same seems to 

 be true, to some extent at least, with regard to the indent character of the grains. 

 It is not clear from the experiments that this character segregates after the !Mende- 

 lian fashion, but it is pointed out by the author that a certain looseness in the 

 method of pollination used makes it impossible to interpret the behavior of this 

 character. With respect to height of plant, all cases tested seem to indicate that 

 there is a blend in Fi and no segregation in later generations. The most important 

 contribution to knowledge is the complete confirmation of the \iew that failure of 

 the Mendelian ratio in the case of blue vs. white aleurone layer is due to defective 

 dominance and not to imperfect segregation. In such crosses the blue appears 

 in ratios almost invariably below expectation, sometimes considerably below, but 

 subsequent breeding of the whites from such a cross shows that enough of them 

 are heterozygotes to make up the deficiency in the number of blue grains in the 

 preceding generation. The author speaks of the "dominance" of the white 

 aleurone layer in this case, but this is not correct, for if the white were really domi- 

 nant in the accepted sense, the crossing of these white heterozygotes with pure 

 whites would give only white offspring; but this was the method used to demon- 

 strate their heterozygote nature by showing that such a cross produces a consider- 

 able proportion of blues. The failure of dominance of blue in these cases is rather 

 to be spoken of as "latency," and the possibihty that there may be another factor 

 involved, as in certain other known cases of latency (invisibility), is suggested and 

 needs investigation. — G. H. Shtjll. 



Anatomy of Lobeliaceae. — The anatomy of the Lobeliaceae has been described 

 by Ybrac,^ who reaches the conclusion that Jussieu's classification is more 

 natural than that of Bentham and Hooker, and that the family ought to be placed 

 between the Compositae and Campanulaceae, instead of representing only a tribe 

 of the latter. Many genera and species have been examined, and the author has 

 not confined himself to the stem and leaf alone, but gives also many points of inter- 

 est about the root structure, and a special chapter is devoted to the medicinal spe- 

 cies. Characteristic of the familv is the occurrence of articulated laticiferous 

 ducts, which are located in the leptome and accompany this tissue in the roots, 

 the stem, and the leaf; but the aquatic Lobelia Dortmanna is destitute of latex. 

 None of the Lobeliaceae possesses bicollateral mestome strands, while these are 

 frequently observed in the Campanulaceae and Compositae (Ligulifiorae) ; the 

 mechanical tissue is only represented by collench)Tna in the stem, there being no 

 stereomatic pericycle. The leaves are bifacial so far as concerns the distribution 

 of the stomata (on the dorsal face), but the chlorenchyma is mostly of ahomogene- 



7 Yd-r.\c, F. L., Recherches anatomiques sur les Lobeliacees. Thesis, pp- ^^5- 

 Lons-Le-Saunier. 1905. 



