NOTES AND ABSTRACTS. 



C85 



Ovule of Casuarina, Development of. By H. 0. Juel (Flora, 

 vol. xcii. 1903, pp. 284-293 ; t. viii., 1 cut). — The author has examined 

 two species, one, undetermined, from near Algiers, and C. quadrivalvis 

 Labill., from Naples. The cells of the archespore or embryo-sac mother- 

 cells, distinguishable by their large nucleus, by two successive complete 

 divisions give rise each to a row of four distinct cells. This must be 

 regarded as a true tetrad division. The first mitosis is preceded by the 

 synapsis and dolichonema stages, and is essentially heterotypic ; the 

 number of chromosomes is probably twelve. Dark masses of condensed 

 cytoplasm something like centrospheres appear one at either end of the 

 original cells, but do not divide and are found after division at the distal 

 side of the nucleus of the apical and the basal cell of the tetrad respectively ; 

 they are probably trophoplasmic. — M. H. 



Oxygen, Withdrawal of, its Effect on Plants. By Max Dude 

 (Flora, vol. xciii. 1904, pp. 205-252, figs. 1-2). — The subjects were placed 

 in vessels from which the air was first exhausted and then replaced 

 by hydrogen. Seeds and spores bear the absence of oxygen for a 

 long time but finally die. After the termination of shorter exposures 

 germination is delayed ; after longer exposures the germlings are 

 weakened and imperfect. Vegetating Moulds are damaged and finally 

 killed by the process ; the time needed varying with the nutrient solution 

 (e.g. glycerin 1 h., cane sugar 4 h.). Vegetative organs of flowering 

 plants resist the treatment for a few hours only, though parts capable of 

 resuming meristic activity may show it after some days ; if the treatment 

 is arrested before death, all vital processes are delayed for some time 

 longer. Young, actively developing parts suffer most, and roots more 

 than shoots [subterranean more than aerial?]. Higher temperatures 

 favour the effect of deprivation of oxygen. — M. H. 



Palms, The Collecting" of. By U. Dammer (Not Konig. Bot 

 Berlin, Bd. IV., pp. 59-61 ; July 10, 1903).— A note on how to select and 

 preserve properly representative portions of these — for herbarium purposes 

 — unwieldy plants. — H. M. W. 



Pampas Grass, The Nomenclature of. By 0. Stapf (Gard. 

 Chron. No. 885, p. 399 ; Dec. 12, 1903).— This plant was known for many 

 years as Gynerium argenteum, but in 1897 Dr. Stapf pointed out in a 

 note in the ' Gardeners' Chronicle ' (Ser. iii. vol. xxii., p. 358, 378, 396) 

 that it did not belong to that genus, and proposed the name of Cortaderia, 

 which has been adopted by various botanists. It now appears that 

 Lemaire recognised in 1855 that the Pampas grass was not really a 

 Gynerium, and named it Moorea, but did not use the name when writing 

 of the plant subsequently. Dr. Stapf says : " Deeply convinced of the 

 necessity of limiting changes of names to a minimum, I refrain under 

 the circumstances from resuscitating Lemaire's name." — G. S. S. 



Papaw, The Story of the. By F. B. Kilmer {Bull. Dep. Agr. Jam., 

 vol. i., pt. 8, p. 181). — Regarding Central America as the native country 

 of Carica Papaya, it is now abundant between the isothermal lines of 

 77° ; and is cultivated north and south of them. 



