308 GENETICS [Bot. Absts. 



used as testers. Author's summary follows: "1. In Cunningham ella there does not exist 

 sexual dimorphism. — 2. C. echinulata plus and minus, or Mucor V plus and minus as separated 

 by Blakeslee, are unable to form progametes or gametes when contrasted with any one of 26 

 cultures of C. bertholletiae. — 3. Many of these cultures of C. bertholletiae were able to form 

 zygospores when contrasted with certain other cultures of this same species. — 4. There ex- 

 ists a selective power in some strains to form zygospores with certain other strains. This 

 condition of pseudo-heterothallism cannot be explained at present.— 5. There exists a con- 

 dition in some strains which might be called hermaphroditism. — 6. In none of the hermaph- 

 rodite strains did branches of the hyphae conjugate. — 7. Zygospores were produced only 

 when 2 strains were contrasted whose gametes were compatible."— A. F. Blakeslee. 



2097. Byrnes, Esther F. Experiments in breeding as a means of determining some re- 

 lationships among Cyclops. Biol. Bull. 37: 40-49. S pi. July, 1919. — Author seeks by exam- 

 ination of adults and of the different developmental instars to settle the question as to the 

 validity of the two common forms "Cyclops signahis var. coronatus (C.fuscus Jurine) and Cy- 

 clops signatus var. tenuicornis (C. albidus Jurine)." Author finds certain adult characters 

 distinct for the two forms and for the immature stages mentions the presence on the fourth 

 swimming feet of a certain seta in a fully developed condition (together with a hairiness at 

 the base of the segment having this seta) in the one form, and small or absent (together with 

 a lack of the hairiness) in the other form. She finds these differences constant in generation 

 after generation of her cultures. — A. M. Banta. 



2098. Clute, Willard N. Age and protoplasm. Amer. Bot. 25: 107-108. 1919.— Com- 

 menting on the contention of Casper L. Redfield that the protoplasm of animals improves 

 as it grows older, it is pointed out in support of this theory that, in the peony, pink daisy 

 (Pyrethrum hybridum), and some melons, the characters of the flowers and seeds are influenced 

 by the age of the plant. Doubling in peony and pink daisy is a matter of progression for 

 several years. — W. N. Clute. 



2099. Cobb, Frieda, and H. H. Bartlett. A case of Mendelian segregation in Oenothera 

 pratincola. Ann. Rept. Michigan Acad. Sci. 20 (1918): 151. 1919.— This is a preliminary 

 abstract of: Cobb, Frieda, and H. H. Bartlett. On Mendelian inheritance in crosses be- 

 tween mass-mutating and non-mass -mutating strains of Oenothera pratincola. Jour. Wash- 

 ington Acad. Sci. 9: 462-483. Oct. 4, 1919. [See next following Entry, 2100.]— #. H. Bartlett. 



2100. Cobb, Frieda, and H. H. Bartlett. On Mendelian inheritance in crosses be- 

 tween mass-mutating and non-mass-mutating strains of Oenothera pratincola. Jour. Wash- 

 ington Acad. Sci. 9: 462-483. Oct. 4, 1919. — In crosses between Oe. pratincola mut. formosa 

 (true-breeding, revolute-leaved mutation from Oe. pratincola strain E) and f. typica strain E, 

 inheritance is matroclinic. Oe. pratincola strain C pollinated by mut. formosa gives a matro- 

 clinic progeny. Mut. formosa pollinated by strain C gives, in the Fi, f. typica, in the F2, 

 Mendelian segregation of 3 f. typica: 1 mut. formosa (the latter breeding true, and, of the for- 

 mer, one third breeding true, two thirds repeating the splitting.) — Explanation offered: two 

 types of gametes occur in Oe. pratincola, a (usually female) and /3 (usually male), the a carry- 

 ing some character determiners not represented in the /3. Mut. formosa arose from f. typica 

 strain E by loss of the factor for flatness in the a portion of the a gamete. Therefore, change 

 being in the a (female) gamete only, inheritance is matroclinic in crosses between mut. for- 

 mosa and f. typica strain E. Strain C differs from strain E in having, in addition to the factor 

 for flatness in the a portion of the a gamete, a Mendelian factor for flatness, present in both 

 a and /3 gametes. Therefore strain C X mut. formosa gives a progeny of f . typica which breeds 

 true (a gamete concerned was normal), while mut. formosa X strain C gives a progeny of f. 

 typica which splits in the next generation (a gamete concerned had lost the factor for flat- 

 ness, allowing the Fj individuals which were recessive for the Mendelizing factors for flatness 

 to show the revolute-leaved character. Restated, 



