200 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Studies in the Cyperacese : the Grouping of the Carices.* — 

 T. Holm criticises the various sub-divisions of the genus Carex, which 

 have been proposed from the time of Linnasus onwards. He attempts a 

 classification of the two groups, Vignece (with two stigmas), and Carices 

 genuince (with three stigmas), which he considers must be maintained, 

 in accordance with the principles suggested by Drejer. The author 

 considers the two to be parallel groups evidently sprung from certain 

 monostachyous types, and branching out in several more or less re- 

 stricted "greges." He gives a synopsis of the characters of these 

 " greges " and the species assigned to them, placing first the simplest 

 species (when such are represented in the shape of monostachyous 

 species) as Hebetated, then the supposed central types, and thirdly as 

 JDesciscentes, certain species which cannot be placed in direct sequence 

 with the centrales, and which to some extent show transition to other 

 "greges." Thirty-nine greges are maintained, fifteen under Vignece, 

 and twenty-five under Carices genuince ; many of these are established 

 for the first time by the author. 



Association of Chalk-loving and Chalk-avoiding Species.f — 

 S. Aubert describes a remarkable association of Calluna vulgaris and 

 Vaccinium uliginosum, two well-marked calcifuge species with an other- 

 wise typical chalk-loving flora, in a dry chalky grassland on the high 

 Jura. The predominating species in the area, which formed a rectangle 

 of about 200 by 30 metres, sloping to the south-east at an elevation of 

 1090 metres, was Calluna vulgaris. The other dominant plants were 

 Alchemilla vulgaris, Potentilla Tormentilla, Phyteuma orbiculare, San- 

 guisorba dictyocarpa, Carex glauca, and Hypericum quadra nguhwi. In 

 a turf-pit, several hundreds of metres to the east, Calluna vulgaris 

 grew in abundance, and this may have been the source of the Calluna 

 found on the chalk-soil. It is affirmed that the latter had been 

 dominant on the area in question for fifty years. The author gives the 

 result of a chemical analysis of the soil, and discusses at length the 

 question of calcicolous and calcifuge species, but is fain to admit that 

 he can find no explanation for the fact which he describes in the present 

 case. "It is simply a fact of observation which shows how little 

 general theories are verified by local facts, and how little is the advance 

 we have made in the knowledge of the intimate relations between the 

 different elements of the soil and the vegetation which it supports." 



American Plants Naturalised in Spain.J — D. L. Aterido describes 

 the extensive growth near Santander of Stenotaphrum americanum, an 

 American grass which occurs also in West Tropical Africa and at the 

 Cape. Associated with it are other American plants, such as Agave 

 americana, Nothoscordum fragrans, Cyperus vegetus, and another grass 

 Digitaria piaspcdoides. The author also gives a list of nearly sixty plants 

 of American origin which have become established in the peninsula, 

 among which we note Lepidium virginicum, five species of Oenothera, 

 including (E. biennis, seven species of Opuniia, Solidago canadensis, 

 four species of Datura, and eight of Amarantus. 



* Amer. Journ. Sci., xvi. (1903) pp. 445-64. 

 f f Bull. Soc. Vaudois Sci. Nat., xxxix. (1903) pp. 3139-84. 

 X Bolet. Soc. Esp. Hist. Nat., iii. (1903) pp 326-9. 



