696 



SCIENCE. 



[N. S. Vol. VIII. No. 203. 



Observations on some Hybrids between Drosera 

 intermedia and Drosera filiforinis. Peofes- 

 soR John M. Macfaelane. 

 The author reported the discovery and 

 described the appearance of a number of 

 Droseras which are morphologically inter- 

 mediate between the species named, in 

 number and position of the flowers, num- 

 ber and shape of the leaves, scales, etc., so 

 that he thinks there can be no reasonable 

 doubt as to the occurrence of hybrids be- 

 tween these two species. Drawings were 

 exhibited and explained. 



On the Validity of the Genera Senna and Chamce- 

 crista. Chaeles L. Pollaed. 

 A eecoed of further observations on the 

 structure of the flower of Cassia ChamcBcrista, 

 on the floral arrangement of which Profes- 

 sor E. L. Greene commented in a recent is- 

 sue of Pittonia. He found that the corolla 

 exhibits a torsion of 90° to the left and 

 thereby differs materially from that of Cas- 

 sia proper. Other characters were adduced 

 to prove the distinctness of the two genera. 



Species Characters among theViolets. Chaeles 

 L. Pollard. 



Development of the Pollen Gi'ain in Symploear- 

 pus and Peltandra. B. M. Duggae. 

 Division of the primitive archesporium is 

 of the vegetative type, and the number of 

 chromosomes present is that of the whole 

 number of the sporophy te. The resting nu- 

 cleus of the definitive archesporium has a 

 large nucleolus taking the chromatin stain 

 in the Flemming combination. The retic- 

 ulum is a loose net very slightly chromatic. 

 In the cytoplasm there is no differentiated 

 zone of kinoplasm. The contracted state 

 of the chromatin thread iu the late retic- 

 ulum or early spirem was found abun- 

 dantly at a definite period in the life-history 

 of these cells prior to actual division. In 

 this condition staining is diflicult, and the 

 return from this phase is characterized es- 

 pecially by a loosening of the ribbon in one 



perfect coil, thus truly imitating the spirem. 

 The spirem ribbon becomes nodulate,and 

 finally segmentation is preceded by a bend- 

 ing back of the ribbon at definite points 

 and the disappearance of the chromatin 

 along the connecting linin. The formation 

 of the spindle is multipolar and the chromo- 

 somes are centrally as well as peripherally 

 arranged. The nucleolus is peculiar in as- 

 suming various shapes and in showing linin 

 connections with the general ribbon. The 

 first division, in general, indicates that there 

 is a longitudinal division of the chromo- 

 somes, although in Symplocarpus there is 

 a suggestion that the first division may be 

 the reducing division and hence transverse. 

 In the second division the daughter seg- 

 ments separate longitudinally in both cases. 

 There is no return of the nucleolus prior to 

 the second division, but a true dispirem is 

 formed. This is in accord with studies on 

 Liliacese, but differs from what is found in 

 some dicotyledonous plants. In the divis- 

 ion of the microspore nucleus the nucleus 

 migrates to one side of the cell and the en- 

 tering kinoplasm forms a multipolar some- 

 what barrel- shaped spindle. This finally 

 becomes completely attached at one pole, 

 forming a truncated cone, while the other 

 pole of the spindle may be truly conical. 

 This fixity of the spindle causes the unequal 

 division of the cell body, necessitating the 

 small generative cell. This method of di- 

 vision (fixity of one pole) seems to be char- 

 acteristic of such divisions in many plants. 



Notes on the Embryo-sacs of Certain Monocotyle- 

 dons. K. M. Wiegand. 

 Recent investigations by Dr. Wiegand 

 tend to show that the two extreme types of 

 embryo-sac formations as illustrated by 

 Lilium and Canna are related in a manner 

 not before observed. In Convallaria, which 

 represents the transitional type, a septum is 

 formed after the first division of the hypo- 

 dermal nucleus, but not after the second. 



