716 



SCIENCE 



[N. S. Vol. XXXVII. No. 958 



Subsequently Ingenitzky," a student of Pro- 

 fessor Cholodkovsky's, made a much more de- 

 tailed study of these glands and distinguished 

 them clearly from the trichogens, the enlarged 

 hypodermal cells which give rise to the hairs. 

 It seems, then, very clearly established that 

 the so-called aerophores have no function of 

 rendering the larvae more buoyant, but are 

 really toxopliores, as Cholodkovsky proposed 

 to call them. The role of rendering the larvae 

 more buoyant may much better be ascribed to 

 the long, thin hairs which, as the Russian ob- 

 server points out, have an unmistakable re- 

 semblance to the pappus of some plant seeds. 

 Wm. a. Eiley 



SPECIAL ARTICLES 



IS THE BIENNIAL HABIT OF CENOTHEEA RACES 

 CONSTANT IN THEIR NATIVE LOCALITIES? 



The recent article^ on " (Enothera and 

 Climate," by E. E. Gates, is of particular in- 

 terest to me since, for the past few years I 

 have had in culture several of the races of 

 CEnothera " hiennis " from the vicinity of 

 Ithaca, iST. Y. Two (possibly three) of these 

 races which are predominantly biennial in 

 character have in culture in their native lo- 

 cality produced annual individuals. In one 

 case (No. 2, (Enothera nutans) the seed was 

 planted during March, 1911, and in May the 

 boxes were kept in the garden with one trans- 

 planting until June, when they were trans- 

 planted in the open garden. From the experi- 

 ences of the season of 1912, these rosettes of 

 1911 started in the greenhouse in March were 

 not so far advanced as they would have been 

 had the seed been planted in the open garden 

 in April. Three out of about 50 or 60 came 

 into flower early in September. Eosettes of the 

 intermediate stage were well formed in August 

 but these three individuals did not form the 

 dense rosettes so characteristic of the others in 

 late autumn. Two of these September flower- 

 ing individuals were potted and taken into the 



° Ingenitzky, I., ' ' Zur Kenntniss der Driisen- 

 haare der Nonnenraupe (Ocneria monacha)," 

 Borw Soc. Ent. Eossicee, XXX., pp. 129-134, 

 pi. VIII., Figs. 9-11, 1896. 



> Science, N. S., 37: 155, 156, 1912. 



greenhouse, where they flowered all winter. 

 In the spring they were removed to the garden 

 and kept in their pots, where they continued 

 to flower until some time in August, thus flow- 

 ering continuously for eleven months. An- 

 other race (No. 1, (Enothera pycnocarpa) 

 under the same conditions remained strictly 

 biennial. 



In a third race (No. 17) seed was planted 

 directly in the garden in the early spring of 

 1912. Eight or ten out of about 200, without 

 the formation of rosettes, came into flower in 

 August, matured seed and died. They were 

 strictly annual. The others are now in the 

 rosette stage. 



In another race (No. 16), possibly identical 

 with No. 2, the seed was planted directly in 

 the garden on the same day as No. 17. Out 

 of about 300 individuals one did not form a 

 rosette. It came into flower in August, 

 formed seed and died late in September. This 

 individual was annual, but it remains to be 

 seen if it is a mutant from this race, which 

 can not be determined before the rosettes of 

 the other individuals now passing the winter 

 have come into flower. 



From my experience in the culture of (Eno- 

 theras, which is not extensive it is true, I have 

 come to the conclusion that their behavior as 

 to a strict biennial habit even in their native 

 locality may be difl^erent under culture either 

 in the garden or greenhouse from what it is 

 in the open under feral conditions. Fully 

 formed rosettes potted in the autumn and 

 taken into the greenhouse, kept there during 

 the winter and removed to the garden in the 

 spring did not form stems nor come into 

 flower any earlier than those which wintered 

 in the garden. 



Another feature of considerable interest 

 which has appeared in connection with some 

 of my cultures may be mentioned here, but an 

 account of the more important results are re- 

 served until after another season's experi- 

 ences. The feature to which I refer is the 

 possibility of certain races of (Enothera be- 

 coming perennial or of taking on a perennial 

 habit under certain conditions. Several 

 plants of (Enothera nutans which matured in 



