506 



SCIENCE. 



[X. S. Vol. XXI. Xo. 53.3. 



1. Hybrid characters are expressed in the 

 structure of the vascular cylinder as well 

 as in external alterations of form and color. 



2. Catalpa speciosa is not in any way 

 concerned in the production of the hybrid. 



3. Teas' hybrid Catalpa is the product of 

 a cross between C. kacmpferi and C. 

 higtionioides, thus confirming the conclu- 

 sions already reached by Sargent on the 

 basis of external morphology. 



4. The dominant characters of the hy- 

 brid, as expressed in the internal structure, 

 are those of the Japanese parent as simi- 

 larly manifested externally. 



5. The resultant characters are most 

 strongly exhibited in transverse section, less 

 so in the tangential and least of all in the 

 radial. 



6. Teas' Catalpa presents a degree of 

 stability directly comparable with that ex- 

 hibited by the willows, various species of 

 Crataegus and many other plants which are 

 commonly recognized as distinct species. 

 Its origin is in direct harmony with Men- 

 del's law and it should be given the status 

 of a species for which the name Catalpa 

 teasi is appropriate. 



Polyembryony in Celtis (illustrated) : Pro- 

 fessor J. W. TouMEY, Yale Forest School. 

 In the spring of 1901, 500 of the normal 

 one-seeded fruits of Celtis occidentalis 

 were planted. Seedlings grew from 98 

 per cent, of these fruits. The total num- 

 ber of seedlings obtained, however, was 

 580 ; that is, a little more than 10 per cent. - 

 of the fruits sown produced more than one 

 seedling. 



In 1902 and again in 1903 the drupaceous 

 fruits of this specii s were again sown, with 

 similar results. In 1903 the fruits of 

 Celtis reticulala and Celtis Mississippiensis 

 were sown. Both of these species, in some 

 instances, developed more than one seed- 

 ling from a single fruit, but not so fre- 

 quently as in Celtis occidentalis. 



On examination of a large number of 



ovaries in various stages of development, 

 and mature fruits of Celtis occidentalis it 

 was found that the development of more 

 than 1 embryo in a single fruit arose as 

 follows: (1) From double fruits. In 1,000 

 fruits examined 3 double ones were found. 

 (2) From the development of two seeds 

 within the same fruit. In 400 fruits ex- 

 amined 7 were found which contained 2 

 ovules each. In each of these cases one 

 ovule was much larger than the other and 

 both were attached to the wall of the ovary 

 by a common funicle, indicating that they 

 both arose from the same fundament. (3) 

 From true polyembryony. In 200 of the 

 young ovules that were fixed and sectioned 

 16 were found with from 2 to 4 embryos 

 within a single embryo sac. In these cases 

 the embryo arose directly from the tissue 

 of the nucellus at the micropylar end of 

 the ovule. "When seeds, containing ovules 

 resulting from true polyembryony were 

 sown usually all of the embryos developed, 

 as high as 4 developing from the same seed. 

 The young seedlings that developed from 

 such embryos were often imperfect and 

 more or less grown together. Occasionally, 

 however, they were approximately the 

 same size, perfect and wholly separate. 

 (4) From false polyembryony. From 200 

 of the young ovules fixed and sectioned 3 

 were found where 2 nucelli developed 

 within the same integuments. Each 

 nucellus developed an archespc rium and 

 ultimately an embryo sac. Assuming that 

 both embryo sacs become fertilized and 

 develop normally we would here have a 

 case of 2 embryos within common seed 

 coats ; both developing from fertilized eggv 

 This is believed to be very unusual among 

 angiosperms. 



Nymplma and the Monocotyls: Dr. Henry 

 S. CoNARD, The Johns Hopkins Univer- 

 sity. 



The speaker discussed some observations 

 on the structure and development of 



