194 



SCIENCE 



[N. S. Vol. XXXIII. No. 840 



Grggoire and liis students, Haecker, Strasburger, 

 Bonnevie, JMemec and Lundeg§,rd, a detailed ac- 

 count of the behavior of the chromosomes during 

 rest has until recently been largely neglected, i 

 have endeavored to follow in detail the various 

 changes which the chromosomes of the telephase 

 undergo during their passage into the resting 

 nucleus, to follow their structural changes and 

 arrangement in the resting nuclei, and also to 

 determine how the visible chromosomes are re- 

 formed preparatory to division. During the pas- 

 sage of the chromosomes from the equatorial 

 plate to the poles, they exhibit a progressive 

 alveolation and vacuolation. Transparent spots 

 appear in each chromosome. Each chromosome 

 is composed of chromatic granules, closely massed 

 in a linin substratum. By means of the progres- 

 sive alveolation and vacuolation these chromatic 

 granules are eventually separated. This process 

 continues until conspicuous anastomosing vacuoles 

 appear on the inside, increasing the size of the 

 chromosome. These enlarged chromosomes often 

 touch each other laterally, but never anastomose, 

 as has been described by some authors. Each 

 chromosome ultimately forms an independent 

 reticulum. The reticulum of the resting nucleus 

 thus consists of a number of these smaller ele- 

 mentary reticula. Conversely, during the earlier 

 prophases of division, the chromosomes become 

 more condensed and distinct and, joining end to 

 end, give rise to the spirem, which is at first 

 broad and reticulate, but eventually becomes 

 densely chromatic. The mature spirem is not 

 continuously chromatic, but consists of the indi- 

 vidual condensed chromosomes united serially by 

 visible linin intervals. In the writer's opinion 

 the results strongly support the view of the indi- 

 viduality of the chromosomes. 



The 'Nuclear Conditions in Certain Short-cycled 



Rusts: Edqak W. Olive, South Dakota State 



College. 



Two general types of short-cycled lepto- and 

 micro-rusts have been recognized with reference 

 to the time of inauguration of the binuoleate 

 condition. In one type, the binueleate condition 

 arises at the base of the young teleutospore sori. 

 This type is illustrated by Pucoinia elegans, P. 

 asteris and P. malvacearum. In the other type, 

 the binueleate condition arises at some indefinite 

 point earlier in the life history, in the vegetative 

 mycelium. Illustrations of this type are appar- 

 ently more numerous. 



Except the one species, Puccinia elegans, in 

 which sexual cell fusions have already been 



worked out, the method of initiation of the bi- 

 nueleated condition is still problematical. 



In two forms, evidences of occasional multi- 

 nucleated cells were found in the young sori. 



Uromyoes Rudheckice was found to present an 

 enigmatical variation, in that all the cells, teleu- 

 tospores as well as vegetative mycelium, were 

 discovered to possess each but one nucleus. No 

 explanation can be offered at present for this 

 unique phenomenon. 

 Teratological Forms of Oxy coccus maorocarpus : 



C. L. Sheae, U. S. Department of Agriculture. 



A malformation of the cranberry plant, of both 

 economic and scientific interest, occurs about 

 Grand Eapids, Wis. Metamorphy of the floral 

 organs is tne most important and striking char- 

 acteristic of the trouble. The flowers become 

 erect instead of drooping, the calyx and corolla, 

 and frequently the stamens and pistil, are changed 

 into leaf-like structures. In the most aggravated 

 cases the floral axis is elongated and the floral 

 organs are represented by whorls of small leaves, 

 or the flower may be replaced by a slender shoot 

 bearing small alternate leaves. No insects or 

 fungi have been found to bear a causal relation to 

 the malformation. It is believed to be due, pri- 

 marily, to prolonged and excessive stimulation of 

 vegetative growth. 

 Rust of Tsuga canadensis: Peeley Spaulding, 



U. S. Department of Agriculture. 



Collections of the rusts occurring on Tsuga 

 have been made for several years. Most of them 

 have proved to be Peridermium Peckii. '±iiia 

 ranges from Wisconsin to northern New York and 

 Vermont, southward to North Carolina. It Has 

 been collected on the new host Tsuga oaroliniana 

 in North Carolina by Dr. A. H. Graves. The 

 collections not belonging to Peridermium Peckii 

 were separated into two forms: one on the young 

 shoots, and the other on the green cones, in both 

 cases on T. canadensis. The latter form is named 

 Coeoma tsugce sp. nov. The former presents no 

 apparent specific dirference from the latter, and 

 it is for the present considered identical with it. 

 Fresh material is necessary to determine this 

 point with certainty, however. 

 A Plea for Organized Research in the Tropics: 



Pehe Olsson-Seftee. (Introduced by Wm. 



Trelease. ) 



A general discussion of the history of scientific 

 research as carried on by various nations, with 

 a special consideration of the conditions in trop- 

 ical America and the numerous possibilities for 

 work in all lines of botany. 



