420 BOTANICAL GAZETTE [may 



listed. Seven circinellas are described, of which C. minor and C. aspera are 

 given as new. In the genus Rhizopus, of which 22 species are recognized, 

 physiological characters, such as ability or inability to grow on potato above 39 C. 

 and power to ferment different carbohydrates, are used in addition to the usual 

 distinguishing morphological characters. Material received from the Amsterdam 

 center under the name of Mucor norvegicus is identified as R. nodosus. Seventeen 

 species are recognized in the genus Absidia, of which A.spinosa,* homothallic 

 and heterogamic species, is described as new. In addition to the 

 genera mentioned, Cunninghamella elegans is described as new. 



In addition to the systematic part of 113 pages, an introduction of 47 P a *? es 1S 

 devoted to methods of isolation and cultivation, and to a discussion of the sexual 

 reproduction in the group, together with the results of a cytological investigation 



forms 



formation 



sexual differentiation had extended to the separation of distinct male and female 

 races would show a differentiation in the uniting gametes. In no heterothalltc 

 form, however, has there been shown to be any constant difference in the size 

 of the gametes, such as occurs in a few of the homothallic species, where, since t e 

 zygospores are produced between neighboring filaments of the same plant, a ess 

 specialized sexual condition might be supposed to exist. In Absidia Orc.n ts 

 Lendner finds that the circinate outgrowths, which typically arise from^ 0^ 

 suspensors, are at times produced from but one, which has been cut off rom 

 large progamete that he considers female. This he claims an indication of sexiu 

 differentiation, as also the frequent inequality in the gametes of Rhizopus. 

 these facts he concludes that the (+) and (-) races are potentially h ™ ™*^ 

 but with the opposite sex more or less completely suppressed. The sugges 10 

 the sexual races may be potential hermaphrodites is in line with our -now 

 of higher forms, but to formulate this as a conclusion and to claim that the ^ 

 and larger gametes formed by a single sexual race are male and female respec ^ 

 as Lendner would imply, is certainly going beyond the facts in an ^ 

 reviewer has shown that in Rhizopus the larger gamete is derived sometim ^ tba]lic 

 the (+) and sometimes from the (-) plant, and that similarly in the hetero ^ 

 species of Phycomyces the outgrowths (which Lendner, p. 3 8 > wrong \ Sa> the 

 from the zygospore itself) are confined sometimes to the ( + ) and son J® tl ™ f QUt . 

 (-) suspensor. The inconstant difference in size of gametes and beha ^^ ^ 

 growths from the suspensors in Absidia Orchidis is probably merely nu^ ^ 



character and of no sexual significance. In A . Orchidis also, is gur 



Viptwccn two u uu 

 appears to be an arrested stage in the formation of a zygospore u ^ ^^ 



growths from the same suspensor, and therefore belonging to t e sa^ ^ fed 

 race. If this is used as an argument for the contention just mentl0nC ta ' ken aS to 

 should be established beyond doubt. Even if the author were not mis a^ ^ 



terminations 



difficult to follow in a tangle of other filaments, these two arrested i^^ of a 

 be thought to have arisen adjacent to each other at the stimulus o c j temp0 - 

 third branch, which came from the opposite sex but had remained in 



rary contact with them. 



