Morphologie der Zellen, Gewebe und Organe. 119 



sharply differentiated from the cytoplasm. The pyrenoid splits into several starch 

 bodies but no definite central area is present. The paper includes a survey of 

 the literature on mitosis in the simpler plants. Gates. 



302) Thomas, N., Notes on Cephaleuros. In: Annais of Botany, Bd. 27, 

 S. 781—792, PI. 59, 1913. 



This interesting green epiphyllous alga is found attached to the cuticles of 

 leaves in the tropics, taking the form of little flat discs of cells somewhat re- 

 sembling ColeocJiaete. Its life-history is imperfectly known. Material was studied 

 of three forms, two of which occurred together on leaves from Ceylon and a 

 third came from Barbadoes. The latter differs in being sub-cuticular, in develo- 

 ping "rhizoids", in producing sub-cuticular zoosporangia, and in having a pro- 

 nounced effect on the leaves it inhabits. 



The most interesting feature of these forms is the method of cell division. 

 Radial walls grow inwards from the margin of the disc, and Irans verse septa are 

 forraed, not at the end of these walls but part way up, so that loose ends of 

 the radial walls are left. 



In some cases the alga is associated with fungal hyphae. Gates. 



303) Moreau, Fernand, Etat histologique de la bulbillose des lames 

 chez un Agaric. In: Bull. trim. Soc. mycologique de France, Bd. 29, Heft 3, 

 S. 341—345, 1913. 



La bulbillose des lames, decouverte par Patouillard, consiste dans leur 

 multiplication en un grand nombre de fragments arrondis dont chacun a ete 

 consideree par cet auteur comme une sorte de bulbille, et dans l'absence de basides. 



Moreau a etudie l'evolution nucleaire de ces corps, constitues par un 

 massif cellulaire qui presente les memes variations du noyau que la baside, ce 

 qui vient ä l'appui de l'opinion de Patouillard. Gatin. 



304) (xraham, Margaret, Studies in nuclear division of Preissia com- 

 mutata. In: Annais of Botany, Bd. 27, S. 661 — 679, PI. 54—55, 1913. 



The material of this Liverwort was collected in the gorges at Ithaca, New 

 York, and a study was made both of vegetative division and sporogenesis. In 

 vegetative mitoses the nucleus first elongates and the reticulum becomes more 

 prominent. A spireme is formed which contracts around the nucleolus. The spireme 

 then uncoils, becomes even in thickness, and Segments into the chromosomes. 

 The haploid number of chromosomes is probably 8. In telophase, the chromo- 

 somes elongate and form finally slender threads which unite to form the resting 

 reticulum. The spindle arises from granulär masses at the ends of the nucleus in 

 early prophase. A hyaline cone-shaped cap appears between these granulär mas- 

 ses and the nuclear membrane. In these caps fibres appear which form the be- 

 ginning of the spindle. Neither centrospheres nor centrosomes were found. 



In sporogenesis the nucleus enlarges and the reticulum becomes a lepto- 

 nema. In synapsis, the spireme forms a knot bearing prominent chromatin bo- 

 dies. Distinct chromomeres show in the thread emerging from synapsis. The 

 nucleolus suddenly disappears while the chromosomes are being formed aud when 

 the nuclear membrane is still intact. The spireme segments after a second con- 

 traction to f-orm the heterotype chromosomes. Hyaline caps appear in the cyto- 

 plasm at the poles of the cell. The spindle subsequently formed has blunt and 

 broad poles. The chromosomes were observed to be two-parted in anaphase of 



