iqiq] current literature 271 



tion between chondriosomes and plastids, Mottiers has brought the Hterature 

 up to 1918. 



La Valette St. George, working upon the male cells of insects, gave the 

 first description of chondriosomes. He introduced the term cytomicrosomes. 

 Meves, in 1904, gave the first description for plants, using the tapetal cells of 

 anthers of Nymphaea for material. Lewitski, in 1910, was first to claim that 

 chondriosomes give rise to plastids. A little later he made a comparative 

 study upon living and fixed material, showing conclusively that the bodies are 

 present m hving cells. The investigation by Mottier, to which reference has 

 already been made, proves that some chondriosomes give rise to chloroplasts 

 and leucoplasts. He also believes that the chondriosomes are permanent 

 organs of the cell, of equal rank with the nucleus. Of course he recognizes 

 that chloroplasts and leucoplasts also multiply by division. His claim that 

 chondriosomes are concerned in the transmission of hereditary characters does 

 not seem to be so well supported. Some investigators have suggested that 

 chondriosomes transmit characters of the cytoplasm and that the chromosomes 

 transmit characters of the nucleus. 



It seems to be established that chondriosomes are not artifacts, that they 

 multiply by division, and that some of them give rise to plastids. Their role 

 in heredity, if they have any, still remains to be demonstrated.— C. J. 

 Chamberlain. 



Trimorphism of Pontederia.— The family Pontederiaceae is notable as 

 containing the only known heterostyled species among monocotyledons (with 

 possibly one exception), and is further remarkable among heterostyled plants 

 as furnishing the only recorded examples of distinctly zygomorphic flowers in 

 such plants. Hazen^ has recently published interesting observations on 

 Pontederia cordata L. Leggett had reported in 1875 that this species was 

 trimorphic, and the present paper is a detailed study of the flower forms, pol- 

 lination, insect visitors, etc. 



The tubular perianth is slightly zygomorphic and in all 3 flower forms 

 presents 2 sets of stamens: a longer set of 3 on the anterior side of the flower, 

 and 3 short-stalked stamens on the posterior side of the flower. In 2 of the 

 flowers the upper stamens protrude beyond the open perianth. The long- 

 styled stigma reaches a height of 12-13 • 5 mm., the mid-styled form 7-8 mm., 

 and the short-styled form ^-:i . 5 mm. above the base of the ovary. The ratios 

 of the average heights of the 3 lengths of pistils are approximately as 100, 60, 

 and 22. 



While the arrangement of parts is different in each of the 3 flower forms, it 

 results in 2 sets of stamens adjusted to each length of pistil. The 6 legitimate 

 crosses which may take place between the 6 sets of stamens and the 3 different 



5 MoiTiER, D. M., Chondriosomes and the primordia of chloroplasts and leuco- 

 plasts. Ann. Botany 32:191-214. pi. i. 1918. 



* Hazen, Tracy E., The trimorphism and insect visitors of Pontederia. Mem. 

 Torr. Bot. Club 17:459-484. 1918. 



