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Proceedings of the Royal Academy of Sciences of Paris. 

 BOTANY. 



Sterility of Hybrid Plants. On the 9th of May, M. Dutrochet 

 addressed a letter to the Academy, in which he attributes the steri- 

 lity of hybrid plants to the imperfection of their sexual organs. In 

 the flowers of some species of cherry-trees (those derived from the 

 union of the prunus cercesus and the prunus aviuni), the stamina 

 have no pollen ; their antherae form a compact mass which does not 

 divide into pollenic or fertile dust, as is the case with fruitful cherry- 

 trees. 



Irregularity of the Organs of Vegetables. On the 6th of June. 

 M. Dutrochet communicated some observations on this subject, 

 which he considers as presenting a phenomenon similar to that 

 which he has observed in some animals, viz. an invariable abortion 

 of some of the parts, so that these plants are in fact consistent 

 or perpetually recurring monstrosities. In an Alpine cytisus, 

 which was terminal, M. Dutrochet observed six petals, four disposed 

 in a cruciform manner, and above them two contiguous petals placed 

 alternately. The manner in which these last were placed prove that 

 there must have been two others which have become abortions, so 

 that the papilionaceous flowers were originally regular flowers, hav- 

 ing eight petals disposed in two ranges alternately. Three of these 

 petals constantly become abortions, and the five remaining ones form 

 the standard, the two wings and the two pieces of the keel. Irre- 

 gular flowers are always lateral; when by chance they become ter- 

 minal, they resume their original regularity, because they have then 

 equal room for developement on every side. 



Abortions and Irregularities of Flowers. On the 13th of May, 

 M. Adriende Jussieuread a memoir on this subject, in which he entered 

 into a very detailed examination of the structure of flowers, parti- 

 cularly of the family Malpighia. The flowers of this family have 

 been generally described as regular, or, if authors have pointed out 

 some irregularities, they have cited them as exceptions, whereas they 

 are constant and numerous. In fact, the segments of their calyx are 

 similar in very few cases, their petals scarcely ever ; their stamina 

 differ both in number and in form and dimension, and the number of 

 the ovaries is never in proper proportion to the other parts of the 

 flower. M. Jussieu's object is to account for and systematize these 

 irregularities. 



A complete flower presents several orders of organs disposed in 

 an equivalent number of concentric circles ; in the dicotyledones (to 

 which this memoir principally relates) the number of parts springing 

 from the same circle is generally five, or a multiple of five; these 



