34 ECOLOGY, PLANT GEOGRAPHY [Bot. Absts., Vol. IV, 



238. Knoll, Fritz. Gibt es eine Farbendressur der Insecten? [Are insects trained in 

 the recognition of colors?] Naturwissenschaften 7: 425-430. 1919. — The question of the uni- 

 form attraction of certain colors for the honey bee and a few other insects is discussed. The 

 paper contains many field observations on the color of the flowers visited by the insects. By 

 certain procedures the attraction of the insects by means of chemical substances (odors, honey, 

 etc.) is excluded. The insects worked with seem to be color-blind to reds and greens but in 

 no case are they entirely color-blind. — Orton L. Clark. 



239. Kraus, E. J., and H. R. Kratbill. Vegetation and reproduction with special ref- 

 erence to the tomato. Oregon Agric. Exp. Sta. Bull. 149. 90 p. 22 fig. 1918.— See Bot. Absts. 

 1, Entry 1402; 3, Entry 1487. 



240. Lohr, P. J. Untersuchungen iiber die Blattanatomie von Alpen- und Ebenen-pfianzen. 

 [Investigations on the leaf anatomy of alpine and lowland plants.] Recueil Trav. Bot. Neer- 

 land. 16: 1-62. Fig. la-Jfi (8). Tab. 12. 1919. — The author investigates the leaf structure 

 in a large number of alpine plants and those of ordinary level in Switzerland (168 species in 

 98 genera). The tissue volume is measured by micrometer, and an average of at least three 

 specimens considered as standard. The injection method of Unger with modifications is 

 used for the determination of the intercellular volume, which is found hydrostatically. A 

 special method is used for small leaves as in Empetrum nigrum. From six to fifty leaves of 

 every specimen are taken for determination and margins of error estimated. The leaf char- 

 acters studied are: (1) thickness, (a) influence of exposure to light, (b) altitude under same 

 exposure, (c) soil under same conditions; (2) epidermal structure, (a) thickness of cuticle, 

 (b) thickness of epidermis, (c) distribution of stomata; (3) mesophyll structure, (a) influ- 

 ence of exposure on relative volume of palisade and aeration tissues, (b) influence of moisture 

 in formation of same, (c) isolateral and dorsiventral leaves; (4) intercellular volume, (a) 

 influence of exposure, (b) altitude, (c) soil moisture, (d) nature of substratum; (5) weight 

 of dried and live leaves. The author concludes that there is no characteristic leaf structure 

 for all alpine plants, since they are too much affected by location and other things that also 

 determine the structure of lowland plants under similar conditions. A greatly developed cuti- 

 cle is the only character that seems to be a mark of alpine plants. Thickness of leaf in 

 sun plants is emphasized in alpine conditions, shade leaves being relatively thinner. — J. A. 

 Nieuwland. 



241. Long, Frances Lotjise. The quantitative determination of photosynthetic activity 

 in plants. Physiol. Res. 2 : 277-300. June, 1919. [Serial no. 16.]— Influence of light intensity, 

 submergence under water, infection by parasites, etc., on net photosynthetic activity of leaves. 

 [See Bot. Absts. 3, Entries 1375, 1452, 2685, 2833.]— B. E. Livingston. 



242. Lumsden, D. Orchid breeding. Jour. Internat. Gard. Club 2: 203-212. 5 fig. 

 1918. — A genetical paper with remarks on symbiosis in orchids. Root fungi are regarded as 

 necessary for the successful growth of orchids, especially in the seedling stage. The relation- 

 ship is regarded as one of mutual parasitism. A separate organism is required for each tribe, 

 and often for each genus and species. [See Bot. Absts. 2, Entry 950.] — 0. E. White. 



243. Ltjndegardh, Henrik. Ekologiska och fysiologiska studier pa Hallands Vadero. 

 II. Till k'annedom om strandv'axternas fysiologi och anatomi. [Ecological and physiological 

 studies on Hallands Vadero, Physiology and anatomy of the shore plants.] (Swedish, with 

 English summary.) Bot. Notiser 1919: 1-39. 1919. — In 1917 an ecological station and a 

 physiological laboratory were established on Hallands Vadero, a small island in the Kattegat, 

 off the west coast of Sweden. In part I (Bot. Notiser 1918; see Bot. Absts. 4, Entry 292) 

 a vegetation analysis was made after the Raunkiaer method, and comparison made with 

 other localities. The osmotic pressure of the leaf cells was determined for most of the halo- 

 phytes, and the mesophyll was found generally to have a greater pressure than the epidermis. 

 A low pressure was found in the succulents, Sedum maximum and Suaeda maritima. A mod- 

 erate pressure was found in the halophytic and somewhat succulent Cochlearia officinalis, 



