334 Fioristik etc. — Angewandte Botanik. 



brous leaves are t'ollowed by partially hairy, then by completely 

 hairy leaves. Other plates show the distribution on partially hairy 

 leaves, the rule being that the hairs are localised mainl}^ on those 

 parts most remote from the main water supply. Seasonal differences 

 in pnbescence and in leaf anatomy are also illustrated. In discussing 

 the effect of environment on leaf structure, it is indicated that 

 whiie hairs and palisade cells are developed most under conditions 

 which protnote transpiration or hinder ab.sorption, yet in Spiraea 

 leaves normally h'dxry are not altogether plastic under changed 

 conditions, although on the whole the curves of hairiness follow 

 closely the mean curves of evaporation and light-intensity. A coin- 

 parison is admissible between the development of epidermal hairs, 

 the palisade cells, and the root-hairs; in so far as these are influen- 

 ced by external conditions, the same factors are operative in each 

 case. Hair production is promoted by marked periodic fluctuations 

 in the turgor of the hair-producing cells. A review of knowledge 

 of swamp xerophytes leads to the conclusion that xeromorphy is 

 useful to plants exhibiting it but the special devices are probably 

 required to meet extreme rather than normal conditions. While 

 edaphic and climatic factors are important in determining xeromor- 

 ph}' in marsh plants, it is pointed out that the problems of indivi- 

 dual species must be considered, their growth forms with resulting 

 differences in exposure and shelter, the duration of the vegetative 

 period , and other factors all play a part. W. G. Smith. 



Holm, T., Medicinal plants of North America. 63. Cheno- 

 podiurn anthehninticiun L. and Ch. ambrosioides L. (Merck's Re- 

 port. XXI. p. 178—181. f. 1-15. July 1912. New York.) 



While both species are deemed equally medicinal, only the 

 former is official in United States, and the latter in Europe; 

 oleum chenopodii U. S. P. is distilled from Ch. anthehninticuni , and 

 largely so in Maryland, where this species is rare, however, in 

 comparison with the other. Various stages of development are 

 described and figured, and it is shown that Ch. ambrosioides is a 

 perennial, and not an annual as generally stated. The seedling has 

 a deep tap-root which winters over, and the vegetative reproduction 

 is securred by buds in the axils af the cotyledons. The primary 

 root persists for several 5'ears, and numerous buds develop in the 

 axils of the low^ermost slem-leaves, producing aerial shoots in the 

 next season. The anomalous structure characteristic of a number of 

 Chenopodiaceae as already noticed b}'^ Unger, occurs, also, in Ch. 

 ambrosioides the anatomy of which is described and illustrated. 

 While the structure of the capiflary roots is normal, the thick roots 

 exhibit the peculiar development of several concentric bands of 

 collateral mestome-bundless from a broad meristematic tissue inside 

 the secondary cortex. A like structure recurs in the stem so soon 

 as secondary formations commence. The leaf is thin; stomata and 

 glandulär hairs occur on both faces of the blade; the chlorenchyma 

 consists of a Single Stratum of short palisade-cells, covering an open 

 pneumatic tissue with cells containing chrystalline sand; the midrib 

 contains an arch of mestome with stereome on the leptome-side, 

 and with a large mass of thinwalled water-storage-tissue. The petiole 

 is quadrangular in cross-section, with five separate mestome-strands. 



Theo Holm. 



Holm, T., Medicinal plants of North America. 64. Kalmia 



