NOTES ON RECENT RESEARCK. 



889 



Chlorophyll and Amidon in Stems. 



Chlorophyll and Amidon Formation in Stems. By J. 



D'Arbaumont {An7i. Sc. Nat. Bot. xiii. pp. 319-423 ; xiv. pp. 125- 

 210 ; 1901). — Amidon granules, proteid bodies distinguished by brown 

 coloration with iodine, appear just behind the growing point in abun- 

 dance, soon to disappear except in the endodermis, reappearing in inter- 

 nodes whose growth in length has ceased ; after a period of summer 

 increase reaching a maximum in August or September, they decrease in 

 number towards winter, when they disappear, to reappear the following 

 spring in the now one-year-old twig. Two kinds of chlorophyll bodies 

 are distinguished, and their evolution followed throughout the seasons of 

 the first year, till they disappear in winter and reappear next spring. 

 The research has included about sixty species of trees and shrubs. The 

 results are carefully recorded, but the large number of species dealt with 

 favours exceptions, and the absence of summaries is disappointing. The 

 origin of the chloroplasts, amidon, and other bodies dealt with is, 

 however, a fundamental question. The results differ somewhat from 

 those of Sachs, Schimper, or the more recent views of Belzung and 

 Mer.— TF. G. S. 



Botanical Classification. 

 Classification of the Veg*etable Kingdom based on the 



Egrg". By Ph. van Tieghem (Ann. Sc. Nat. Bot. xiv. pp. 213-390 ; 1901). 

 The egg is the starting-point of a new individuality resulting from 

 variations due to the two parent nuclei ; the sum of the individualities 

 of the units produces the characters of the race ; and the races are the 

 vegetable kingdom. This is the hypothesis ; the aim is to found a classi- 

 fication based on it and free from defects of systems in use. Dealing 

 with a subject so wide, the paper is an object-lesson in exposition and 

 brevity, while Van Tieghem's reputation gives it weight. Some of the 

 chief points must suffice here. The first division of plants is into Diodees 

 and Adiodees. The former have the gametes borne on a rudimentary 

 body (prothallus) produced from the adult parent by a diode — a term 

 introduced by Van Tieghem some years ago to indicate what is generally 

 termed the spore. The group of Diodees is, therefore, synonymous with 

 the vascular plants — the Ferns and higher plants. The Adiodees have 

 the egg formed directly on the parent, and include the Alg«, Fungi, and 

 Mosses. The Adiodees are subdivided into Tomiees and Atomiees. In 

 the latter the egg is liberated from the parent, and develops directly into 

 a new individual. In the group Tomiees the egg is not liberated from 

 the parent, but develops into a rudimentary body or " tomiogone," which 

 produces special cells — tomies — and these are liberated and produce plants 

 like the parent. For example, in the mosses the tomiogone is the spore- 

 bearing part, and the tomies are the spores. Van Tieghem advocates the 

 term " tomie " instead of the somewhat vague " spore," and distinguishes 

 them from the diodes which produce a prothallus. Further division of 

 the groups into isogamous and heterogamous and other subdivisions 

 should be followed in the original paper. The result is that while the 

 groups of Mosses and Hepatics remain intact, the Algjv and Fungi are 

 mingled in a startling way, yet one which probably represents the modern 



