No. 1, August, 1921] PHYSIOLOGY 77 



ORGANISM AS A WHOLE 



511. Beau, Clovis. Bur le role trophique des endophytes d'Orchidees. [The nutritive 

 role of endophytes of orchids.] Compt. Rend. Acad. Sci. Paris 171 : i)75-C)77. 1920.— The small 

 amount of food stored in the very minute seeds of orchids indicates that the mycelium of the 

 endophyte supplies necessary foods from the surrounding medium at early stages of develop- 

 ment. Experiments were performed with germinating orchid seed in Petri dishes. A block 

 of nutritive gelatin was introduced and the culture infected with the endophytic mycorhiza. 

 The hyphae were positively chemotropic towards gelatin and a connection is soon established 

 by the hyphae between the gelatin and the seed. If these hyphae are destroyed the seed cease 

 developing even though other hyphae may connect the seeds with distilled water. This may 

 explain why some orchids may even reach the blooming stage in an aetiolated condition with 

 little or no chlorophyll or light. — C. //. Farr. 



512. Church, A. H. The building of an autotrophic flagellate. Bot. Mem. [Oxford] 

 1. £7 p. 1919. — The author discusses the evolution of an autotrophic flagellate of pelagic 

 plankton comparable with that from which the ancestral forms of the Phaeophyceae may 

 have been derived. Evolution is considered and briefly discussed with reference to the fol- 

 lowing factors: Ionic relations, the external source of energy, photosynthesis, proteid-syn- 

 thesis, balance of carbohydrate synthesis and proteid synthesis, growth, day and night, 

 surface-tension, contractibility, differentiation of plasmatic tracts, polarity, the flagellum, 

 binary fission, failure and death, holozoic nutrition, flagellar nutrition, plasmogamy and the 

 origin of sexual fusion, differentiation of flagella, comparative dimensions, encystment, 

 and formation of the cell wall. — /. S. Cooley. 



513. Jones, H. A. Physiological study of maple seeds. Bot. Gaz. 69: 127-152. 2 fig. 

 1920. — This is a study of the viability of the seed of the sugar maple {Acer saccharum) and 

 the river maple {Acer saccharinuni) . The sugar maple seed mature in the fall, contain much 

 fat and protein but little carbohydrate, and pass through a period of after-ripening before 

 germination. The river maple seed mature in the spring, contain much starch but little fat 

 and protein, and must germinate almost at once if at all. — The seed of the river maple lose 

 their viability when the water content is reduced to 30-34 per cent. Temperature plays but 

 little part in determining the critical point of water loss. The seed may be kept in a vigorous 

 viable condition for a considerable time if stored over water at 0°C. Respiratory activity 

 in the desiccating seed at25°C. first decreases slightly, then rises to a maximum, then gradually 

 falls to zero as desiccation progresses. After a slight initial increase, catalase activity 

 gradually decreases in the desiccating seed, but it increases enormously during the early stages 

 of germination. A gradual decrease in peroxidase activity accompanies desiccation. — Sugar 

 maple seed after-ripen best at temperatures near 5°C., with a good supply of oxygen and mois- 

 ture, and show at that time a considerable increase in free-reducing sugars. Catalase activity 

 increases greatly with after-ripening and germination, and there is also a slight increase in 

 peroxidase activity. The hypocotyl as well as the entire embryo has a distinct alkaline re- 

 action in both dormant and after-ripened seed. Fully after-ripened seed will remain in this 

 condition for a long time if kept moist at — 5°C. — H. C. Cowles. 



514. Shull, C. a. Susceptibility gradients. [Rev. of: Child, C. M. (1) Axial suscep- 

 tibility gradients in algae. Bot. Gaz. 62: 89-114. 1916; (2) Further observations on axial 

 susceptibility gradients in algae. Biol. Bull. 31: 419HI40. 1916; (3) Susceptibility gradients 

 in the hairs of certain marine algae. Biol. Bull. 32: 75-92. 1917; (4) Experimental alteration 

 of the axial gradient in the alga Griffithsia Bornetiana. Biol. Bull. 32 : 213-233. 1917 ; (5) Dem- 

 onstration of the axial gradients by means of potassium permanganate. Biol. Bull. 36:133- 

 147. 1919.] Bot. Gaz. 69: 187-188. 1920. 



515. Walker, Leva B. Biology and culture of the higher fungi. [Rev. of: Boyer, G. 

 Etudes sur la biologic et la culture des champignons superieurs. 116 p., 4 pi., 20 fig. Bordeaux, 

 1918 (see Bot. Absts. 5, Entry 1931).] Bot. Gaz. 69: 188-189. 1920. 



