THE BULB BOOK 351 



Under this term the author includes those species which occur in 

 the inundation-area of freshwater associations and which vary 

 according to the amount of water present. One hundred and 

 fourteen species have been investigated, as well as numerous 

 locality-forms, and the area over which the author has worked 

 includes the West European and Mediterranean floras as well as 

 the Central European. A subdivision into zones and groups is 

 made on morphological and biological grounds depending on the 

 appearance of aerial leaves, floating leaves and submerged leaves, 

 as well as on the existence of one or two leaf-forms (homoblastic 

 or heteroblastic). 



Zone i. includes thirty-six species which are essentially 

 homoblastic and comprise submerged forms with reduced organs 

 (unbranched or slightly branched stems and small leaves). They 

 are distributed among seven groups according to the development 

 of the leaf. Here belong Lysimachia vulgaris, Hydrocotyle vul- 

 garis, Cicuta virosa, &c. 



Zone ii. includes eighty-eight species, which comprise sub- 

 merged or floating forms, but always show a strongly developed 

 leaf-surface. There are eight groups which are characterised as 

 homoblastic or heteroblastic, and by the presence of aerial, floating, 

 or submerged leaves and a greater or less development of the leaf- 

 surface. Some general considerations follow, in which the following 

 points are referred to among others — optimum growth of water 

 forms, dwarf forms, presence of aerenchyma, duration of life of 

 locality forms, resting periods, and presence of cleistogamous and 

 submerged flowers. 



The volume concludes with an index of the plants referred to 

 in the text, and a list of the books and papers cited. 



Dr. Gliick's valuable and suggestive contributions to our 

 knowledge of the biology and morphology of aquatic plants will 

 conclude with a fourth volume, which is in preparation, and is 

 entitled " Submerse und Schwimmblatt-flora." A "R "R 



The Bulb Book, or Bulbous and Tuberous Plants for the Open Air, 

 Stove and Greenhouse : containing particulars as to Des- 

 criptions, Culture, Propagation, dx., of Plants from all parts 

 of the World, having Bulbs, Corms, Tubers, or Bliizomes 

 {Orchids excluded). By -John Weathers. Illustrated ])y 

 the Author. Demy 8vo, cl. pp. xv. 471, 312 figures. Price 

 15s. net. Murray. 

 It is necessary to cite in full the title of this latest addition to 

 the not inconsiderable number of volumes which stand under 

 Mr. Weathers's name, as the abridgement — " The Bulb Book " — 

 which appears on the back of the volume would give no adequate 

 notion of its contents. Not only are tuberous and rhizomatous 

 plants included, but, " as almost any plant with a swollen root- 

 stock or thickish creeping roots is called ' bulbous ' in popular 

 parlance, plants with sucli peculiarities have been considered in 

 the present work." With this explanation, the surprise with which 

 one finds in it such plants as Gypsopliila paniculata is removed. 



