432 



SCIENCE. 



[N. S. Vol. IV. No. 91. 



the wood of the thickened portion of the 

 diseased branch. 



(4) In Pinus strobus diseased at the root 

 with Agaricus melleus an increase in the 

 number of resin ducts of the wood takes 

 place in the whole plant above the diseased 

 part. 



(5) In the wood of branches of Abies 

 pedinata diseased with Phoma abietina, and 

 in young seedlings of the same species, ab- 

 normal resin ducts are found only above 

 the constricted portion of the branch. 



An apparently undescribed Cassia from Missis- 

 sippi: By C. L. Pollard. 

 This is a remarkable Cassia, allied to C. 

 chamcBcrista, but distinguishable by its vir- 

 gate habit and strict pods, collected in 

 northern Mississippi by S. M. Tkacy. It 

 proves, upon cultivation, to warrant its 

 separation as a distinct species, for which 

 the name C. Tracyi is proposed. 



A discussion of the order Pesizinece, Schroter : 



By E. J. DuRAND. 



The author gave a brief history of the 

 classification of the fleshy Discomycetes 

 from the time of Linnseus, together with 

 the ideas of modern systematists regarding 

 the same plants. Especial attention was 

 given to those of Schroter. The latter 's 

 views were discussed in the light of investi- 

 gations, made by the author during the 

 two years, touching the structure of these 

 plants, illustrating the bases of their divi- 

 sion into families. 



A Bacterial Disease of the Squash-bug (^Anasa 



tristis): By B. M. Duggar. 



The author gave in brief the characters 

 of a contagious disease first observed in a 

 laboratory breeding cage. Many successful 

 experiments were reported with both 

 squash-bugs and young chinch-bugs. Iso- 

 lation of the pathogenic bacillus and its 

 growth on various nutrient media were de- 

 scribed, likewise the microscopic characters 

 and the distribution of the bacteria within 



the tissues of the host. Mention was also 

 made of a toxic principle excreted by the 

 organism, in an infusion of which many in- 

 sects die almost immediately on immersion. 



Grass flora of Iowa : By L. H. Pammel. 



In the absence of the author the sub- 

 stance of the paper was given by J. M. 

 Coulter. 



Iowa lying between the two great rivers, 

 respectively the Mississippi and Missouri, 

 embraces an area of 56,025, it is well 

 watered by its numerous streams and small 

 lakes, all of which are intimately con- 

 cerned in the distribution of plants. Among 

 the streams are some of considerable size. 

 About two-thirds of the State is drained by 

 rivers that flow into the Mississippi and its 

 tributaries. The largest wooded area is 

 conflned to the Mississippi and its tribu- 

 taries. These wooded areas offer condi- 

 tions that have greatly modifled the distri- 

 bution of grasses in this State. The country 

 is not broken, but northeastern Iowa is ex- 

 tremely rugged. Along the Missouri occur 

 the loess hills, with steep embankments and 

 a loose friable soil. Concerning our grass 

 flora the State is not greatly diversified. "We 

 have north, south, east, west, extra-conti- 

 nental and introduced species. In the 

 number of species the State has less repre- 

 sentatives than ]N"ebraska on the west, than 

 Illinois on the east and Missouri on the 

 south. The southern indigenous types pre- 

 dominate, fellow ed by northern. Only 

 eleven of our species are typical western ; 

 thirteen are extra-continental, and fifty-five 

 are introduced. Blue grass is the most 

 abundant of our grasses. This is followed 

 by Phleum pratense, introduced grass, and 

 Hordeum jubatum, Sind Elymus Canadensis, fol- 

 lowedby two typical Southern plants Ajidro- 

 pogon provincialis and Andropogon scoparius. 



A Contribution to our hnotvledge of the rela- 

 tion between growth and turgor: By Ed- 

 win B. COPELAND. 



