1917] HUTCHINSON— KETELEERIA 127 



this case the nucleus corresponding in origin to the tube nucleus 

 has taken the central position. In the struggle the nucleus which 

 is most centrally placed gains the ascendency, the others being 

 crowded to the wall. 



Morphology of the ovulate strobilus.- 



me 



of the ovulate strobilus. — The anatomy of 

 jVL has been studied by Aase (i). "In Keteleeria 

 Fortunei one bundle originates near the base of the gap in the 

 strobilus cylinder and supplies the bract. It remains undivided 

 throughout its course. Two bundles, one from each side of the 

 gap, supply the scale; the two bundles soon unite, forming one 

 inverted bundle, that is, its xylem faces the xylem of bract." 

 However, in the early stages the strands connected with the 2 

 ovules are separate. The evidence supports the theory that the 

 scale with its megasporangia represents a fertile bud in the axil 

 of the bract. 



The material studied shows that at the time the pollen is shed 

 the megasporangium has reached the mother-cell stage. There is 

 only one megaspore mother cell and it is the fourth cell from the 

 epidermis (fig. 9), characters which still further emphasize the 

 relation of Keteleeria to the Abietineae. 



Sieve tubes. — The sieve tubes of Keteleeria are large, 8-10X 

 200-400JU, and are well differentiated. Concerning the sieve tubes 

 of gymnosperms, DeBary (5) states that "the oblique terminal 

 faces are directed toward the radial planes. Sieve plates are placed 



in one or two longitudinal rows over the terminal faces and the 



remainder 



form 



spots separated by high intervening portions. These spots are 

 coarsely latticed, while in the cavities of the coarse lattice the very 

 delicate sieve structure is seen." The appearance as seen in a 



described, and this 



structure 



H 



and 



fig. 6. However, transverse and tangential sections show no 



ncrs r\r Hpnrp^i'nnc in the walls of the sieve tubes. The 



thicken 



appearance of "delicate sieve structures' ' described for radial 

 , sections is caused by the presence of granular inclusions in proto- 

 plasmic aggregations which are situated on either side of groups 



