434 ANNUAL BEPORT SMITHSONIAN INSTITUTION, 193 



Mature plants of In, 2n, and 4n types are shown in Plates 1, 2, 

 and 3. 



Flowers, floral parts, and capsules of the balanced types are shown 

 in Plate 4. An increase in size of cells and organs of the plant is 

 the rule in going from In to 4n forms, as is seen in the flowers in 

 the photograph. In comparison with normals (2n), the leaves of In 

 plants are very narrow while those of 4n plants are very broad. The 



Haploid 



(in). 



Balanced Types Unbalanced Type s 



Moaijied Haploids 



/. 



Diploid 

 ^ II "- 



(2n) 



(2n-l) / 



Moaijied Diploids 



(2n + t 



<:> llX 



fen + 2) / 



fentltl) / 



Triploid 



(3n) 



Hodijied Triplolds 



(3n-l) ^ (3n+!) / 



Tetraploid 



(4n) 



% 



Mod 



(4n-l) / 



ied Tetraploids 



(4n + l) / 



(4n+2) / 



^^IIIU./ 



(4n+Ut) ; 



Figure 2. — Diagrams of some chromosomal types found in tlie Jimson weed 



4n capsule is broader and more nearly spherical than the 2n capsule. 

 It will be noted that the odd-balanced In and 3n capsules are much 

 reduced in size, probably because of the small number of seeds which 

 they contain. 



Because In and 3n plants produce such a scanty yield of capsules 

 and seeds, they continue blossoming long after the normal (2n) and 



