964 



SCIENCE. 



[N. S. Vol. XIX. No. 495. 



olus is intimately connected with the nuclear 

 reticulum; that it contains nearly all the 

 chromatin of the nucleus; that this is trans- 

 ferred, previous to division, into the nuclear 

 thread, which is then segmented into chromo- 

 somes; and that in the reconstitution of the 

 daughter-nuclei, the chromosomes become 

 fused into a number of more or less spherical 

 or irregular masses which unite to form the 

 daughter nucleoli." 



NUMBER OF POLLEN GRAINS IN INDIAN CORN. 



In the American Naturalist for December, 

 1881, the writer published a note giving the 

 results of a large number of careful counts 

 and estimates made, a few years earlier as to 

 the number of pollen grains produced by In- 

 dian corn (maize). Briefly, the results were 

 as follows : Average number of stamens in a 

 ' tassel,' 7,200 ; average number of pollen 

 grains in an anther, 2,500; average number 

 of pollen grains produced by a plant, 18,000,- 

 000. 



A recent bulletin (No. Y7) prepared by Pro- 

 fessor P. G. Holden, of the Iowa Experiment 

 Station, gives considerably higher results, the 

 statement being that " careful counts made at 

 this station last year of the number of pollen 

 grains found in an ordinary anther taken 

 from different parts of a great many tassels 

 showed that between 49,000,000 and 50,000,000 

 pollen grains were borne on an average by 

 each tassel." 



THE EARLY FALLING OF BOX-ELDER LEAVES. 



Every one who has watched the box-elder tree 

 {Acer negundo') carefully has noticed that the 

 first leaves to appear in the spring are by no 

 means typical, often being simple, biit deeply 

 cleft, so as to resemble those of the maples, and 

 never having more than three leaflets when 

 compound. These cataphyllary leaves occur 

 on the first and second nodes of the shoots of 

 the season, and even on the third and fourth 

 in extreme cases, gradually approaching the 

 typical five-foliate compound leaves. Within 

 a fortnight of the appearance of the first 

 leaves, and shortly after the typical leaves 

 have developed the cataphylla begin falling 

 from the trees. When this defoliation is at 



its maximum the ground under large trees is 

 covered with the discarded leaves, much as in 

 the autumn. This is so marked that it is one 

 of the objections to this tree on lawns and 

 well-kept grounds. Why these leaves are dis- 

 carded so soon is not plain. We are reminded 

 of the discarding of the primary leaves of the 

 pines, where the matter has gone so far that 

 none of the first crop of leaves are retained. 

 The streets of Lincoln, Nebr., which have 

 many box-elder trees planted along their sides, 

 are now (May 21) littered with these fallen 

 cataphyllary leaves. 



PHILIPPINE PLANT NAMES. 



On request of Captain G. P. Ahem, Chief 

 of the Forestry Bureau of the Philippine 

 Islands, the botanist of the bureau', Mr. Elmer 

 D. Merrill, has prepared a very useful ' Dic- 

 tionary of the Plant Names of the Philippine 

 Islands,' which has been published at Manila 

 by the Department of the Interior of the 

 Islands. It consists of two parts, the first of 

 which is an alphabetical list of the native 

 names with the corresponding scientific names, 

 while the second list includes an alphabetical 

 arrangement of the genera and species, with 

 native synonyms and short explanatory or 

 descriptive notes. The extent of the under- 

 taking may be inferred from the fact that be- 

 tween 4,500 and 5,000 native names are enu- 

 merated. And yet the author himself calls 

 attention to the fact that the present enumera- 

 tion records the native names for ' perhaps 

 twelve to fifteen of the seventy or eighty dia- 

 lects spoken ii) the archipelago.' There is 

 evidently much more work of this kind to be 

 done, and Mr. Merrill is entitled to much 

 credit for the excellence of his list as far as 

 he has carried it. 



Charles E. Bessey. 



The University of Nebraska. 



EXPEDITWN FOR SOLAR RESEARCH. 

 With the aid of a grant of $10,000 from the 

 Carnegie Institution, for use during the cur- 

 rent year, the Yerkes Observatory of the Uni- 

 versity of Chicago has sent an expedition to 

 Mt. Wilson (5,886 feet) near Pasadena, Cali- 

 fornia, for the purpose of making special in- 



