96 ILLINOIS STATE ACADEMY OF SCIENCE" 



It was then evident that although most of the vascu- 

 lar strands were closed, some of the small strands had 

 blind endings. This would mean a dicotyl leaf venation, 

 which was very close to monocotyledony. Immersion 

 in a saturated chloral hydrate solution for twenty-four 

 hours was tried for the same purpose, but with poorer 

 success. 



The fusion of bundle strands to form partial rings 

 is a prominent feature. In some of these, leaf gaps may 

 be seen. 



The rhizome of Nelumbo lutea was studied. It is poly- 

 stelic and shows collateral bundles without cambium, a 

 monocotyl character (Fig. 14). However a few dicotyls 

 are polystelic. Comparison of this rhizome with that of 

 Nelumbo albiflorum shows the same type of bundle for 

 both. Longitudinal sections of adventitious root tips 

 of these two species were studied also, and are both of 

 the usual dicotyl type. They differ only in that the outer 

 cells of N. albiflorum have pitted walls. Conard states 

 (1) that the Nymphaeeae have this type of root struc- 

 ture. 



Why the cotyledons of Nelumbo lutea should develop 

 so peculiarly is difficult to understand. In embryos with 

 a single cotyledon, the latter develops in contact with 

 the ovule wall, which is markedly thicker there than the 

 rest of the wall. This may mean larger food supply 

 and therefore faster growth at that point. Later the sec- 

 ond cotyledon grows with increasing rapidity and very 

 soon overtakes the first. At the same time the meristem 

 in the center grows slowly, the tissues between the coty- 

 ledons very slowly, and we have an apparent dicotyl 

 plant. Before the second cotyledon has grown to any 

 size, the thickening of the ovary wall has disappeared. 



The researches of Coulter, Land, and Farrell show 

 that monocotyledony and dicotyledony mean little and 

 are very easily interchangeable. Farrell (5) found four 

 growing points on the cotyledonary zone of Cyrtanthus. 

 All except one slowed up and a single cotyledon was 

 formed. Coulter and Land (4) found in Agapanthus 

 one completely dicotyledonous seedling, while all the oth- 



