抄録
The chromosome number of 74 species and varieties in Cactaoeae were observed. 1 . The polyploidy of the. each group are as follows., 1 : 2x(2), II :2x(5) 3x(1) 4x(4) 6x(3) 6x(3) 10x( I ) 12x( I ), III : 2x(13) 4x(4). IV : 2x(36) 4x( 1), In these: polyploids 3x, 8x. 10x and 12x have not been known. 2 . The basic number of chr'omosorile in Cactaoeae including Pereskieae is n=11. 3 . No heteroploid was found in this study. 4. The pollen rtLother cells divid, ed at about noon, and the fact ls in accord, with the observation reported by Miss. BEARD. 5. The division of cells in root tip occurred from 7 to 8 o'clock a.m. or from 4 t, o 6 o'clock p. nl. and the observation is somewhat differ from Miss. i3EARD's report. For ascertain the diffefence above mentioned, the root tips of two species-Trichocereus spachianus and Notocactus sudmammulosus-were fixed at intervals of one half or tWo hours duririg 7 o'clock a. m. to 6 o'clock p. m: In the root tips fixed at noon the ', division of cells were scarcely found, but there were many dividing cells fixed at morning Or evening. e . The chromosomes of cacti are very small, and.: there are some difference in size among each species . The size of chromosomes in tropical or desert plants are small in many cases, but not absolutely. So it may not be said that the smaller chromosomes. ls not related to the tropical or succulent plants: 7. There was not found real relation between polyploidy and cold reslstance 8. There was not recognized ariy relation between polyploidy and other characters .
