Audiews, Karyokinesls in MaguoÜa and Liriodendron. 135 



The reduetion tlieoiy in the sense of Weisiuann is supported 

 among Ibotanists by Belajeff, Atkinson and others, Bela- 

 jeff says that the chromosomes of both the first and second 

 division have the form of V's; Y's; and X's — a tact which 

 sei'ves as a proof that the chromosomes retain their jdentity 

 durin g the brief period of rest. 



Guignard in his h\test piiblications^) returns to the former 

 view of Strasbur ger^) — namely that a double longitudinal 

 Splitting of the chromatin takes place during the first division. 

 According to this view the V-shaped daughter chromosomes of the 

 first division results from a second longitudinal Splitting which had 

 taken place at right angles to the first, the segments remaining 

 attached at' one end — the opposite ends di verging to form the V. 



Gregoire^) arrives at this same conclusion and naturally 

 falls into the same error. My owu observations were made upon 

 MagnoUa obovata and Liriodendron Tidipifera. While these plants 

 are far less favorable than mauy monocotyledonous species such 

 as the lilium, yet the behavior of the chromatin may be followed 

 without much difficuliy in nearly all stages. The material was 

 prepared according to the method used by Mottier*) in his 

 studies on Lilium and several dicotyledenous species. 



The resting nuclei of Magnolia obovata are fairly large and 

 in many respects are favorable objects for investigation. In Lirio- 

 dendron Tidipifera the nuclei while showing the same points as 

 to formation and behavior of the chromosomes are much smaller 

 and therefore less to be desired for study than those of Magnolia 

 obovata. There is generally but one nucleolus which is very large 

 and offen gives the appearance as if vacuolated. In the same 

 stage there are at times to be seen two or more nuclei which are 

 always smaller than in the case where a single one was present. 

 These bodies always stained an intense red with safranin. 



During the prophase the nucleus has a very distinct mem- 

 brane and increases greatly in size occupying about one half of 

 the cfell's inferior. The nuclear network reveals very fine meshes 

 in which the small chromatin granules retain strongly the violet 



') Le döveloppment du pollen et la reduetion chromatique dans le 

 Naias major. (Archives d'Anatomie microscopique. T. H. Fase. IV. 20. Mars. 

 1899.) 



') Les centres cinf^tiques chez les veg(^taux. (Annales des Sciences 

 Naturelles. Botanique. Serie VIII. Tome V.) 



^) Karyokinetische Probleme. (Jahrbücher für wissenschaftliche Botanik. 

 1895.) 



^) Les cineses polliniques chez les Liliacees. (La Cellule T. XVI. 2 e 

 fascicule. 



*) Ueber das Verhalten der Kerne bei der Entwicklung des Embryo- 

 sacks vind die Vorgänge bei der Befruchtung. (Jahrbücher für wissenschaft- 

 liche Botanik. Bd. XXXI. 189S). 



*) Beiträge zur Kenntniss der Kerntheilung in den Pollenmutterzellen 

 einiger Dicotylen und Monocotylen. Bd. XXX. 1897. 



9* 



