402 Biologie. — Cytologie und Befruchtung. 



COCKAYNE, L., On the significance of spines in Discaria 

 Toumatou Raoul. (New Phytologist. IV. 1905. p. 79—85. 

 1 plate.) 

 This plant, a common endemic NewZealand xerophytic 

 shrub, foLind on sand-dunes and stony places^, dry river-beds 

 and hillsides, is furnished with numerous sharp spines. The 

 spines are axiliary shoots of limited growth which, with the 

 green shoots, perform most of the carbon assimilation, since 

 the leaves are small, never numerous, and fall off in winter. 

 Seedlings are at first leafy and without spines, but soon pro- 

 duce spines from the axils of leaves. Two seedlings with early 

 leaves and a few spines were transferred three years ago to a 

 Chamber where they were kept constantly in moist air and in 

 feeble light. A photograph given shows a plant after one year 

 in the moist Chamber, and its leafy, spineless habit is very 

 distinct from the normal out-door spiny shoot placed beside it. 

 After the lapse of two years more the plants in the moist 

 Chamber are still leafy. Plants with similar leafy shoots have been 

 observed out-of-doors in very shaded positions. The author 

 therefore considers that „the spines are a direct response to 

 conditions of dryness, and function as a special contrivance for 

 checking transpiration". Reference is also made to the growth 

 of Veronicas and other New Zealand species in dry and 

 moist habitats; these facts are used to support the author's 

 views on xerophytic adaptation, and those of Di eis on the 

 former existence of a „Greater New Zealand" with an 

 eastern semi-desert climate. Smith (Leeds). 



Robertson, Ch., Thestructureof the flowers and the 

 modeof pollination of the primitive An giosperms. 

 (Bot. Gaz. Vol. XXXVIl. 1904. No. 4. p. 294—298.) 



The author attempts in this paper to establish the pro- 

 position that the primitive angiosperms were entomophilous, and 

 that the anemophilous ones are metamorphosed entomophilous 

 flowers whose seemingly simple structure are degraded, not primi- 

 tive. The arguments are based chicfly upon the structure of the 

 gynaecium in the two types in relation to known cases of 

 pollination and upon the habits and evolution of anthophilous 

 insects. , J. A. Harris. 



HUS, H. T. A., Spindle formation in the pollen- 

 mother-cells of Cassia tomcntosa L. (Proc, California 

 Acad. Sei. Vol. CCCXXXIII. 1904. No. 2. p. 329-354.) 



A detailed study of the formation of the spindle, more 

 particulary in the carly stages. The occurrence of a multipolar 

 diarchal spindle is noted, which is more pronounced in the 

 second division. The conclusion is arrived at that the spindle 

 formation in Cassia tomentosa forms a connecting link between 

 the multipolar polyarchal spindle Anlage ordinarily met with in 



