302 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Araeeae, Studies in the. III. By D. H. Campbell (Ann. Bot. xix. 

 July 1905, pp. 329- 346 ; 4 plates). — No. III. of this series deals mainly 

 with the study of the embryo-sac and the embryology of two species, 

 Anthurium violaceum, var. leucocarpum, and Nephthytis liberica. 



A striking fact brought out in the investigation is the extraordinary 

 variability shown in the structure of the embryo-sac itself. In some 

 species the embryo-sac conforms entirely to the angiosperm type. In 

 Lysichiton there is a remarkable development of the antipodal cells subse- 

 quent to fertilisation. In Nephthytis and Aglaonema commutatum, the 

 number of nuclei in the mature sac may be reduced to four or even two ; 

 definite synergida? may be wanting and antipodal cells may be entirely 

 absent. On the other hand, the number of nuclei may exceed the normal 

 and be double the typical number. It is not impossible that some of 

 these variations may be due to pathological conditions. — A. D. G. 



Arceuthobium occidentale, The Dissemination and Germina- 

 tion Of. By George J. Peirce (Ann. Bot. xix. Jan. 1905, pp. 99-111 ; 

 2 plates). — Arceuthobium is a parasite of the Loranthaceaa, chiefly 

 remarkable for its explosive fruits. 



The author investigated .4. occidentale as a living plant growing on 

 Pinus radiata in California and also by laboratory methods. The 

 anatomical structure of the fruit is described, and the method of 

 explosion ; the seeds, it is estimated, may be thrown a length of 25 ft. 

 The germination is also dealt with, the anatomical and physiological 

 features being alluded to ; the general characters of the genus are 

 compared with these of other Loranthacea?. — A. D. C. 



Arnold Arboretum, The. By J. G. Jack (U.S.A. Hort. Soc. 

 Mass. Trans. 1904, pp. 59-76).— The Arnold Arboretum is the first of 

 its kind in North America, a portion of his estate having been left in 

 trust by Mr. Jas. Arnold in 1870 for the promotion of some philosophical 

 or philanthropic purpose at the discretion of the trustees. It is situated 

 in the grounds of the Bussey Institution in Boston, under the management 

 of Harvard University. Its area is over 222 acres, and about three- 

 fourths of it are available for planting. The arranged collection contains 

 at present about 1,200 species and varieties of shrubs and vines, and 

 between 400 and 500 species and as many varieties and hybrids of trees. 

 Already considerable numbers of new plants have been introduced to 

 cultivation, and numerous hybrids have been raised, while between 1880 

 and 1902, 214,650 plants and cuttings and 15,547 packages of seeds were 

 sent as exchanges, and 96,813 plants and cuttings and 6,307 packages of 

 seeds were received. 



A herbarium and library are maintained in connection with the 

 arboretum. Between 45,000 and 50,000 sheets are contained in the 

 herbarium, and the library contains about 10,000 volumes and bound 

 pamphlets, a very large proportion of which have been given by Mr. 

 Charles Sprague Sargeant, the director, to whom the arboretum is so 

 greatly indebted. — F. J. C. 



Arum maculatum and Insects. By Rev. John Gerard (Jourv. 

 Bot. 512, pp. 231-3 ; 8 1905).— The substance of an address delivered 



