178 Anatomie. — Morphologie etc. 



and its Protective Function. (Ann. Bot. XXXII. p. 247—251. 

 1918.) 



This paper gives the result of experimental work designed to 

 test the effect of "barkscraping" uppon rubber trees, wiih a view 

 to elucidating whether such treatment makes the trees more liabie 

 to attack from fungi and insects. The conclusion drawn is that 

 removal of the outer corky layers increases the suscepiibility of 

 the trees to attack by fungi and insects; if the green cork-cambium 

 is left intact the susceptibility to attack is less than when this layer 

 is scraped away. The experiments indicate that the corky integu- 

 ment is the important protective layer against insect and fungus 

 attacks and not the laticiferous layer. Agnes Arber (Cambridge;. 



Briquet, I., Les arilles tardifs et les arilles precoces 

 chez les Cdlastrace'es. Note p reliminaire. (C. R. seanc Soc. 

 phys. bist. nat. Geneve. 1916. XXXIII. p. 67—70. Geneve 1917.) 



Chez les Cdlastracees sont deux modes d'evolution des ovules: 



1. les ovules arrondis ä l'extremite distale, ä micropyle etroit, 

 ä exostome superpose ä l'endostome, a arille tardif. ovoide, ne se 

 d^veloppant qu'ä partir du moment de la fecondation (EvoriymuSj. 

 Celastrus, Gymnosporia, Maytenus). 



2. Les ovules tronques ä l'extremite distale, ä micropj^le evase, 

 ä exostome plus ou moins concentrique ä l'endostome, ä arille pre- 

 coce, campanule, se developpant avant la fecondation et enti^re- 

 ment forme ä l'anthese {Moya). Matouschek (Wien). 



Graham, M., Centrosomes in Fertilization Stages of 

 Preissia quadratn (Scop.), Nees. (Ann. Bot. XXXII. p. 415—420. 

 1 pl. 1918.) 



Centrosomes, while present in the nuclear division figures of 

 many algae and fungi, are absent from these figures in the higher 

 plants. There is very little evidence as to whether centrosomes 

 are present during the stages of fertilization in plants, though in 

 animals it is fairly well established that, in many cases at least, 

 the centre which has been brought into the egg by the sperm 

 divides in the formation of the cleavage spindle. In the Bryo- 

 phytes and Fteridophytes no one has hitherto followed the centre 

 through the processes of fertilisation. From the author's studies 

 on Preissia qiiadrata it is evident that centrosomes as definite 

 granulär bodies are present not only in the divisions just preceding 

 spermatogenesis and, as blepharoplasts, during metnmorphosis, 

 also in the fertilized tg^ at the time when the pronuclei but are 

 paired. Agnes Arber (Cambridge). 



IshikaMra Rigakushi, M., Studies on the Embryo Sac and 

 Fertilization in Oenothera. (Ann. Bot. XXXII. p. 279—317. 1 

 pl. and 14 text figs. 1918.) 



This very detailed and fully illustrated paper deals with the 

 behaviour of the gametophytes and fertilization phenomena in 

 Oenothera nutans and Oe. pycnocarpa and their hj-brids. 



The embryo sac is found to arise from either ihe micropyJar or 

 chalazal number of the sporetetrad; often both of them simulta- 



