Morphologie etc. — Varietäten etc. 245 



There is no evidence throughout the karyokinesis of an equa- 

 tional division of autonomous bodies. The advantage of this form 

 of division over direct divisions appears to lie in the oportunity for 

 escape of the chromidia from the nucleus. 



Spirogyra crassa does not in the behavior of its nucleus in 

 karyokinesis present a unique case, for the stages can be homolo- 

 gized with similar stages in Allium, as typical of the higher plants. 



Jongmans. 



Mottier, D. M., Notes on the sex of the gametophyte of 

 Onoclea Struthiopteris. (Bot. Gazette. L. p. 209 — 213. 1910.) 



During the past two or three years the writer has been coUecting 

 data for a study upon the gametophyte of Onoclea Struthiopteris 

 with reference especially to the dioecious character of the prothallia. 



The results of this study may be summarized as foUows: 



The spores of Onoclea Struthiopteris when grown upon earth, 

 under optimum cultural conditions, produce regularly three kinds 

 of prothallia: small plants bearing only antheridia, the so-called 

 male gametophytes; larger prothallia bearing only archegonia, the 

 female gametophytes; and those bearing both archegonia and 

 antheridia, the bisexual or monoecious prothallia. 



Archegonial prothallia, which continue growth without bearing 

 a sporophyte, sometimes develop numerous small lobes from the 

 older portions, upon which numerous antheridia appear. 



The gametophyte, therefore, is not strictly dioecious, and there 

 is in all probability no sex-determining chromosome. 



It is highly probable that the development of purely male or 

 female gametophytes is not dependent upon conditions of nutrition, 

 but that the sexual tendency is predetermined in the spore. Environ- 

 mental conditions, or the failure of an egg to give rise to a sporo- 

 phyte, owing to a lack of fecundation, may induce the development 

 ot antheridia upon archegonial plants, which continue their growth 

 for some months. 



Pure males result, in so far as is known, under good cultural 

 conditions from the dominance of the male tendency in the spore 

 over the female tendency. Jongmans. 



Rehder, A., Pistillody ofstamens in Hypericum nudißorum. 

 (Bot. Gazette. LI. p. 230-231. 1911.) 



Between the pistil and the stamens of a plant of Hypericum 

 nudißoriDH which was in füll bloom late in the year, a number of 

 peculiar irregularly shaped bodies, representing apparently defor- 

 med carpels, could be observed. The number of the pistillodes in 

 each flower varied from three to about ten, dififering in size and 

 development. Sometimes two of the pistillodes were more or less 

 united at the base, and in a few cases pistillodes were divided at 

 the apex. Pistillodes with fertile anthers were not common. In some 

 of the smaller pistillodes a few of the ovules, particularly towards 

 the apex, were changed into greenish elongated appendages. All 

 other parts of the flower were perfectly normal in all the flowers. 



Jongmans, 



Bast, E. M., A study ofhybrids between Nicotiana bigelovii 

 and iV^. quadrivalvis. (Bot. Gazette. LIII. p. 243—248. 4 Fig. 1912.) 



Two elementary species of N. bigelovii Pursh have been found 



