312 



SCIENCE 



[N. S. Vol. L. No. 1291 



leaf blades, staminate flowers with 3-6 sep- 

 arate sepals and no vestige of the gynecium, 

 and a very short life as compared with the 

 carpellate plant. 



Some staminate plants produce only pure 

 staminate flowers, the expression being purely 

 male, others at first produce besides staminate 

 flowers some abnormal, intermediate flowers 

 with structures differentiated as part ovulary 

 and part stamen, or with normal stamens and 

 a vestigial ovulary which usually has normal 

 stigmas. Frequently ordinary stamens are 

 produced ending in normal stigmas and oc- 

 casionally a pure carpellate flower with the 

 typical sheath-like perianth is developed. The 

 staminate, intermediate plants exhibit various 

 degrees of female expression but apparently 

 in all cases have a strong tendency to become 

 more and more staminate as the blooming 

 period advances, so that at the end only 

 normal staminate flowers are produced. The 

 progression of the sexual state is from female- 

 ness to maleness. 



The carpellate plants usually produce noth- 

 ing but carpellate flowers at first. Occasion- 

 ally, however, there is a plant which will im- 

 mediately begin to grow taller than the 

 average carpellate plant and develop stamens 

 in some of the flowers. These plants appear 

 somewhat intermediate not only in floral 

 development but also in vegetative characters. 

 The vast majority, however, of the carpellate 

 plants develop no such characteristics but 

 begin to produce normal carpellate flowers and 

 seeds and continue with the typical carpellate 

 appearance. After the carpellate plants are 

 well advanced in age, many of them begin to 

 show a change in sex and develop stamens or 

 staminate flowers. Some begin the reversal at 

 a comparatively early jieriod, others not imtil 

 the very last flowers are produced. Some in- 

 dividuals produce only imperfect stamens, ap- 

 parently with defective poUen and with in- 

 dehiscent anthers; others produce normal 

 staminate flowers with dehiscent anthers and 

 apparently normal pollen. In these normal 

 staminate flowers, the perianth consists of 

 typical, separate sepals exactly similar to those 

 in normal staminate flowers produced on 



staminate plants. The reversal from female- 

 ness to maleness is, therefore, of every degree 

 of intensity or completeness both in the 

 number of flowers produced and in the degree 

 of perfection of the sexual structures them- 

 selves. 



A number of individuals appeared normally 

 carpellate and produced 2 or 3 normal seeds 

 at first and then gradually changed to the 

 staminate condition until finally before they 

 began to die of old age purely male sex was 

 being expressed. ITothing but typical stami- 

 nate flowers with dehiscent anthers was being 

 produced. Femaleness had been changed to 

 maleness. In one plot over 50 per cent, of 

 the carpellate plants were finally reversed in. 

 their sexual state to a greater or less degree. 



It is evident, therefore, that in these experi- 

 ments we have a complete reversal of sex from 

 female to male in a species characterized by 

 an extreme dimorphism and this without any 

 manipulation of the plants whatever except 

 that they were grown out of season with a 

 deficiency of light, and a shallow soil heated 

 partly from below. 



Female heredity is at first active and male 

 heredity is latent, and finally male heredity 

 is active and female heredity is latent. The 

 change takes place in the vegetative body and 

 is plainly caused gradually by an internal 

 change of the physiological state or condition 

 of the meristematic tissues from which the 

 fiowers are produced. 



John H. Schatfnek 



Department of BoTAiJY, 

 The Ohio State XjNrvERSiTY 



SCIENCE 



A Weekly Journal devoted to the Advancement <rf 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SOmMCE PRESS 



LANCASTER, PA. GARRISCW, N. Y. 



NEW YO^C, N. Y, 



Entered in the po«l-«ffic« at Laneattii. Pa., u ivcond dui aaatta 



