ABSTRACTS. 



585 



western (N. America) species, showing how the tissues have become 

 adapted to the environmental conditions. — G. H. 



Calanthe madagascariensis, Rolfe. By Sir J. D. Hooker {Bot. 



Mag. tab. 7780). — Nat. ord. OrckidccE ; tribe Epidendrece. Introduced 

 by Mr. Warpur, a Belgian collector ; it flowered at Kew 1890. Pseudo- 

 bulbs small, cylindric, and annulate ; leaves recurved and ridged between 

 the veins. Perianth white, with a purple, rose-red or yellow lip ; 1 inch 

 across, with a slender curved spur. — G. II, 



Calanthes, Culture of. By W. H. White {Orch. Bev. p. 77 ; March 

 1901).— A most interesting and valuable treatise on the culture of the 

 various species and hybrids belonging to the deciduous section of 

 Calanthes. — H. J. C. 



Calcium Oxalate, Probable Function of. By Alb. Schneider (Bot. 

 Gaz. vol. xxxii. p. 142). — The author suggests that the prime use 

 is mechanically strengthening tissues, such as bast ; as a substitute for 

 sclerenchyma, as supplying elasticity, as preventing injury by pressure, as 

 round air-chambers in leaves, &c. He also refers to Kraus's view, that 

 calcium oxalate is a reserve product. — G. H. 



California, Studies on Plants of. By H. M. Hall {Bot. Gaz. 

 vol. xxxi. p. 388, No. 6 ; 1 plate). — Describes Frasera neglecta, n. sp. ; 

 Asclcpias californica, Green; Gilia modesta, n. sp. ; Colliiisia callosa, 

 Parish ; Chcenactis Xantiana, Gray ; C. heterocarpha curia, Gray ; 

 Erigcron Bloomcri, Parish ; Eriogonum nudum, Dougl. ; Aquilegia 

 pubescens, Coville ; Dodecatheoii Jeffreyi redolens, n. var. ; Erigeron 

 salsuginosus, Gray ; Phalacroseris Bolandcri coronata, n. var. — G. H, 



Cameroons, The Botanic Garden in the. By Dr. P. Preuss 

 (Garteuflora, p. 292; 4 illus. ; 1/6/1901).— An account of the Botanic 

 Garden in the German colony of the Cameroons, West Africa, by the 

 Director. Experimental plantations of the chief useful tropical plants 

 (cocoa, coffee, vanilla, rubber-trees, &c.) have been made with a view of 

 determining the suitability of these crops for cultivation in the colony. — 

 J. P. 



Camoensia maxima, Welwitsch. (Bull. Bot. Dep. Jam. vol. viii. 

 p. 88). — An account of this climbing leguminous plant, which bears the 

 largest flower of any plant of the order, the corolla being one foot in 

 length. It is a native of Angola. The flowers are white, edged with 

 gold.— G. H. 



Canada Thistle. By Lyster H. Dewey (U.S.A. Dep. Agr., Div, 

 Bot., Circ. No. 27). — So troublesome a weed has the Canada Thistle 

 become in America that no fewer than twenty- four States have framed 

 laws placing it among the noxious weeds. In the majority of cases a 

 penalty is enforced for allowing seeds to be produced. The more enlightened 

 farmers can readily destroy it, but are greatly handicapped by the ready 

 disseniination of seeds by wind from neglected plots. Mowing before 



