July 25, 1902.] 



SCIENCE. 



139 



nearly all parts of the State, accompanied 

 by the remark that the grass had appeared 

 for the first time. There is no question as 

 to the much greater abundance of this grass 

 the present year. It is of considerably 

 larger size, also, than usual. The sugges- 

 tion is made that the intense heat and 

 drought of last year had to do with the 

 greater abundance of this species of the 

 present year. 



In connection with this case attention is 

 called to the fact that twenty-five years ago 

 after the 'grasshopper raids' the farmers 

 noticed the great abundance of Sporobolus 

 vaginceflorus, which they called the ' grass- 

 hopper grass,' and supposed that it had 

 been brought by the grasshoppers. 



Note on the Fuel Value of Cottonwood: 

 Chas. E. Bessey, Lincoln, Nebr. 

 On the plains where the Cottonwood 

 (Populus deltoidea) is very commonly 

 planted, there is much prejudice against it 

 as a tree having any other value than for 

 shade and windbreak. It is regarded as 

 having low fuel value. Some careful 

 measurements and calculations made by 

 the writer show that on account of its 

 rapid growth it produces more heat-yield- 

 ing fuel in a given time than the trees with 

 which it is usually planted. On a given 

 area in a given time more heat units may 

 be produced than by the use of any other 

 of the commonly planted trees. 



Features of the Flora of Cuha: Chas. 

 Louis Pollard, 1854 Fifth Street, Wash- 

 ington, D. C. (Illustrated with lan- 

 tern. ) 



A general account of the Cuban flora 

 with special reference to the ecological 

 aspects. The various plant zones and plant 

 formations of the island are described, and 

 the characteristic flora of each discvissed. 

 The plants of economic or ornamental 

 value are also briefly discussed. 



The Origin of the Achromatic Figure in 

 Pellia: Charles J. Chamberlain, De- 

 partment of Botany, University of 

 Chicago. 



This investigation deals chiefly with the 

 first two nuclear divisions in the germinat- 

 ing spore. For comparison, however,, 

 mitosis was studied in other phases of the 

 life history. The principal conclusions are 

 as follows: The stimulus to nuclear divis- 

 ion comes from within the nucleus. The 

 asters are cytoplasmic in origin. The caps 

 come from the outer portion of the nuclear 

 membrane or from a Hautschicht surround- 

 ing the nucleus. The appearance and dis- 

 appearance of astral rays suggest that 

 they are concerned in the movement of 

 nuclear matter. The centrosphere is 

 formed by the astral rays, not the astral 

 rays by the centrosphere. This centro- 

 sphere represents a condition intermediate 

 between the well-defined centrosphere of 

 one of the thallophytes, and the centro- 

 someless condition of the higher plants. 

 The spindle fibers, except the mantle fibers, 

 grow from one pole to the other. In early 

 stages two half spindles are often distin- 

 guishable. 



Comparison of the Development of the 

 Embryo Sac and Embryo of Claytonia 

 Virginica and Agrostemma Githago: 

 Mel T. Cook, Greencastle, Indiana. 

 Claytonia Virginica has one arehe- 

 sporium ; it forms one, occasionally two, ta- 

 petal cells, four megaspore cells, of which 

 the lower develops into the sac in the usual 

 manner. Very little enlargement of the sac 

 is evident until the four-celled stage is 

 reached, but after that time it enlarges 

 rapidly and bends to form almost a com- 

 plete circle. The antipodals disappear 

 early; the synergids persist until the em- 

 bryo is quite large. In the formation of 

 the embryo the cell division is very irregu- 

 lar ; the basal cell of the suspensor is small ; 



