i893. NOTES AND COMMENTS. 7 



question of the duality of the process of the Foraminifera, as much as at 

 that of the support afforded to the Theory of Fission by the method of 

 individual examination of the contents of each Foraminiferal chamber, 

 the importance which must be attributed to the question of nucleus among 

 the Foraminifera demands a complementary system of observation. 

 For further detail and argument, the student must be referred to Van 

 den Broeck's paper, as we have already exceeded the space at disposal ; 

 but the communication is so interesting and important that it appears 

 an obvious advantage to quote at this length. 



The Distribution of Seeds. 



We are glad to observe the tendency of biologists at Cambridge 

 to wander more and more from the long-prevalent exclusive fashion of 

 section-cutting, and to attempt to solve some of the wider problems in 

 the science. Another interesting item of research in this direction 

 was communicated to a recent meeting of the Cambridge Philo- 

 sophical Society, when Messrs. J. C. Willis and J. H. Burkill recorded 

 their observations on the flora of the pollard willows near the 

 University town. 



The plants occurring in the tops of the willows near Cambridge 

 have been recorded during the last few years, and amount to 80 

 species, occurring 3,951 times altogether in about 4,500 trees. Of 

 these 80, only 18 form more than 1 per cent, of the total number of 

 records. The rest have only a small number of records. As Loew 

 has pointed out in a recent paper, these plants are of interest from the 

 points of view of distribution of seeds and of epiphytism. Classify- 

 ing them according to means of distribution, we find that 19 species 

 have fleshy fruits; 1,763 records (44*6 per cent.) of these occur. 

 Three species with burrs have 651 records (16*4 per cent.) ; 34 species 

 with winged or feathered fruit or seed have 996 records (25-1 per 

 cent.) ; 7, with very light seeds, have 421 (io*6 per cent.) ; and finally, 

 of plants whose means of distribution is poor or somewhat doubtful, 

 we have 17 species with 120 records (2-9 per cent.). It is thus shown 

 very strikingly how the various distribution-mechanisms succeed, only 

 the better ones showing in the list in any numbers. The bird- 

 distributed plants figure much higher here than in such cases as, for 

 instance, the flora of the churches of Poitiers (Richard). 



The observations show clearly the fact that a seed is only carried 

 a short distance by its distribution mechanism. Plants were always 

 found upon the soil, within 250 yards at most, of those found in the 

 trees. An analysis was made as far as possible of the birds' nests 

 found in the trees, and pieces, often with ripe fruits, of many plants 

 in the list were discovered in them, so that probably this means of 

 distribution is of some importance. 



With regard to epiphytism, Loew considers these plants as 

 beginning this mode of life. Like true epiphytes, they possess good 



