Dec. J3. i9i8 Parasitism of Cronartium ribicola 655 



membrane called the centrosome. This body is apparently the center 

 for the more or less definite convergence and concentration of the chroma- 

 tin strands referred to as polarization. 



(14) The presence of large, irregular, multinucleate cells at the base 

 of the secium is a regular phenomenon and not to be regarded as an 

 abnormal condition. Probably more than one aeciospore chain may 

 arise from such cells. 



(15) There is a remarkable constancy in the process of conjugate 

 division and stability in the nuclear structure throughout the dikaryon. 

 In the dividing nuclei the centrosomes are visible as deeply staining dots 

 at the poles of the spindle. The number of chromosomes is certainly 

 more than two. Possibly eight is the haploid number. 



LITERATURE CITED 

 (i) Arnaud, G. 



I913. LA MITOSE CHEZ CAPNODIUM MERIDIONALE E"" CHEZ COLEOSPORIUM 



SENEciONis. In Bul. Soc. Mycol. France, t. 29, fasc. 3, p. 345-347, 

 pi. 22-23. 



(2) Blackman, V. H. 



1904. ON THE FERTILIZATION, ALTERNATION OP GENERATIONS, AND GENERAL 



CYTOLOGY OF TiiE uredinEae. In Ann. Bot., v. i8, no. 71, p. 323-373, 

 pi. 21-24. List of papers, p. 36S-369. 



(3) and Eraser, Helen C. I. 



1906. FURTHER studies ON THE SEXUALITY OF THE UREDINEAE. In Ann. Bot., 



V. 20, no. 77, p. 35-48, pi. 3-4. 



(4) Christman, a. H. 



1905. SEXUAL REPRODUCTION IN THE RUSTS. In Bot. Gaz., V. 39, no. 4, p. 



267-275- pi- 8- 



(5) — 



1907. THE AliffERNATION OF GENERATIONS AND THE MORPHOLOGY OF THE SPORE 



FORMS IN THE RUSTS. In Bot. Gaz., V. ^4, no. 2, p. 81-101, pi. 7, 

 Literature cited, p. 99-100. 



(6) 



1907. THE NATURE AND DEVELOPMENT OF THE PRIMARY URED03P0RE. In 



Trans. Wis. Acad. Sci., v. 15, pt. 2, p. 517-526, pi. 29. 



(7) CoLLEY, Reginald H. 



1917. Diagnosing white-pine blister-rust from its mycelium. In Jour. 

 Agr. Research, v. 11, no. 6, p. 281-286, i fig., pi. 31. 



(8) 



I917. discovery of internal TELIA PRODUCED BY A SPECIES OF CRON.'VR- 



TiUM. In Jour. Agr. Research, v. 8, no. 9, p. 329-332, pi. 88. Liter- 

 ature cited, p. 332. 



(9) 



1917. PYCNIAL SCARS, AN IMPORTANT DIAGNOSTIC CHARACTER FOR THE WHITE 



PINE BLISTER RUST. (Abstract.) In Phytopathology, v. 7, no. i, 



P- 77- 



(10) Dangeard, p. -A., and Sappin-TrouFFy. 



1893. UNE pseudo-f6condation CHEZ LES ur6din6es. In Compt. Rend. 

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(11) DiTTSCHLAG, E. 



I9IO. ZUR KENNTNIS DER KERNVERHALTNISSE VON PUCCINIA FALCARI^. In 



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