86 



best methods of an enquiry, should the proposed Association decide on 

 their continuation. I shall take the liberty of submitting to you my 

 recommendations in this respect at the end of my report. 



A. — Oondvsions for the practice of Examinations into Origin. 



(a) Weed seeds. — ^The number of new characteristic species, so-called 

 determining species, which occur in these four investigations is very 

 small. We are struck by the frequent occurrence of Trifolium striatum L. 

 in Danish red clover. This is a xerophytic species which needs considerable 

 heat, and which one would hardly expect to thrive and produce ripe 

 seeds in fields of clover, especially in Denmark. A typical Northern 

 species is the Rimiex domesticus L. which was found in Swedish seed, 

 but the seed of which can hardly be distinguished from other Rumex 

 species. From the examinations of ■ Roumanian red clover, we further 

 find tha.t in it occurs Centaurea micrantha Gmel, a sub-species of 

 C. maculosa Lam., which is confined to the Crimea, Bessarabia and 

 Transylvania. It might be profitable to investigate at some time the group 

 of the Centaurea paniculata L. as to species proving provenance. 

 Centaurea pannonica Heuf. is a sub-species of C. Jacea, and will hardly 

 ever be distiiiguishable, in its seed, from the main species. Similarly, 

 it will prove difficult to recognize Rumex difformis Menyhardt, a good 

 Eastern species. In fact, the extuninations of Roumanian red clover 

 have proved the occurrence of a nimaber of species which, up to now, 

 were unknown to iis as weeds in red clover; for instance, Falcaria 

 vulgaris and Passerina annua. It is true, however, that neither of these 

 can be looked upon as characteristic of seeds of Roumanian origin. More 

 important is the result of the establishment of the secondary seeds. 



1. The Danish seed. — -The whole weed flora bears the stamp of the 

 cool and rather moist climate, which is indicated by the predominance of 

 the two TrifoUum species and of the grasses (DactyUs, Lohum, Phleum, 

 Agropyron) and the absence of all species indicating a warmer climate, 

 like Medicago sativa, Verbena officinalis, Thrincia hirta, and also of the 

 Panicum and Setaria species. Certainly there occur such species as 

 Lotus, Daucus and Crepis teotorum, which indicate a locally somewhat 

 warmer climate, but they are not important. The same applies to 

 Ciuhorium; moreover, it is striking that Plantago lanceolata occurs not 

 nearly as frequently (dominancy) as in seed which comes from more 

 southern districts. The occurrence of Matricaria inodora and Sherardia 

 arvensis would merit further investigation. They are both found in 

 Danish seed, but are missing in Roumanian. 



2. The Dutch seed. — -Here too the Panicum and Setaria species, which 

 are so frequent in East European seeds, recede into the background, 

 both as regards constancy and dominancy. On the other hand, species 

 which occur in Eastern Europe, but more rarely than in Western Europe, 

 like Alopecurus agrestis, Rumex acetosa. Geranium spp., Staehys 

 arvensis, Centaurea Jacea and Amoseris, are frequently found. A 

 somewhat warmer climate than the Danish is indicated by Teucrium 

 botrys and Thrincia hirta. But, here too, Medicago sativa and 

 Cichoriimi Intybus are totally missing and Daucus occurs very rarely. 

 Compared with Danish seed, Plantago lanceolata stands out strongly 

 (dominancy) and species missing in the Danish seed, Rumex acetosa 

 and Polygonum convolvulus are frequent in Dutch red clover. The 

 absence of Lampsana and the receding of Sherardia are striking factors. 

 In the seeds from the three Dutch fields of production it was found im- 

 possible to arrive at even moderately accurate marks of distinction, 

 even by most careful comparison. However, the complete absence of 

 the small Gerania (Geranium molle L. and pusillum L.) in the six samples 

 from the Mouse districts, and the rareness of Daucus in the Roosendaal 

 clover, is striking. These three Dutch fields are presented as one in the 

 appendix. 



