No. 2, December, 1921] ECOLOGY, PLANT GEOGRAPHY 73 



ECOLOGY AND PLANT GEOGRAPHY 



H. C. CowLES, Editor 

 Geo. D. Fuller, Assistant Editor 



(See also in this issue Entries 399, 402, 556, 577, 580, 581, 583, 592, 594, 601, 602, 603, 606, 

 607, 608, 609, 611, 625, 642, 745, 747, 751, 752, 797, 801, 802, 803, 804, 805, 806, 807, 809, 



815, 816, 819, 823, 835, 848) 



GENERAL, FACTORS, MEASUREMENTS 



460. T., E. N. Botany at the British Association. Nature 104: 520-521. 1920.— Brief 

 abstracts of various papers are presented including the following: H. H. Thomas on desert 

 flora of western Egypt; H. W. Monckton on flora of London Clay; J. C. Willis on northern in- 

 vasions of New Zealand; Godfery on orchids of Hants and Dorset (members of the section were 

 privileged to see on their expedition one of the rare ones mentioned, Malaxis paludosa); W. 

 Brierley on species concept in fungi; R. R. Gates on mutational versus recapitulatory charac- 

 ters; Miss Saunders on inheritance in Matthiola; Scott on relations of seed plants to higher 

 cryptogams; Salisbury on monocotyledonous features of the Ranunculaceae; Miss Prankerd 

 on movable cell inclusions; M. C.Rayneronmycorhiza and Ericaceae; Priestley on theoretical 

 consideration of root pressure. — 0. A. Stevens. 



461. Thiessen, A. H. Notes on the vertical distribution of temperature. Trans. Utah 

 Acad. Sci. 1 : 55-60. 1918. — This paper was presented to the Academy in April, 1911. — H. C. 



Cowles. 



STRUCTURE AND BEHAVIOR 



462. Agharkar, Shankar. Die Verbreitungsmittel der Xerophyten, Subxerophyten und 

 Halophyten des nordwestlichen Indiens und ihre Herkunft. [Distributional mechanism of 

 xerophytes, subxerophytes, and halophytes of northwestern India, and origin of the mechanisms.] 

 Hot. Jahrb. 56 (Beibl. 124): 1-41. 1920. — An historical account is given in which it is noted 

 that there have been 2 groups of publications, those dealing with structure of the mechanisms, 

 and the other with operation. The region studied is described in detail. It is semidesert 

 in nature, and except along streams most parts are treeless plains. The climate is analyzed, 

 and tables are given showing the conditions existing. A brief description of the result- 

 ing flora is given, the fauna also being mentioned. The distributional mechanisms are divided 

 into active and passive. The active are of 2 sorts, those in which the mechanism is connected 

 with the pericarp. and those in which it is not. The passive are of 5 types adapted to secure 

 distribution respectively by wind, animals, water, and by the opening of seed vessels so as to 

 promote distribution by shaking due to wind or animals; the first 2 are subdivided. The 

 species are classified under these heads in tables. At the end of each table the results are 

 analyzed. Light is thrown on the reasons for the migration of various species from other 

 nearby countries into this region. About 5 per cent of the species are distributed by active 

 means, 50 by wind, 30 by animals, and 15 per cent by being shaken bj' wind or animals. Of 

 the 260 species, 37 are widely distributed, 46 are Indo-lVIalayan, 93 Arabo-African, 38 Mediter- 

 ranean, 1 central-Asiatic, and 45 endemic. — K. M. Wiegand. 



463. Andrews, E. F. Habits and habitats of the North American Resurrection Fern. 

 Torre}'a20: 91-96. 1920. — The most frequent hosts of Poly podium polypodioides (L.) Hitchc. 

 in the southern coastal plain are the post-oak, elm, and tulip-tree. The fern is not a parasite 

 but seems to establish a symbiotic relation with a certain soft moss. Instead of growing in 

 secluded woods, it is found most often on the borders of roads and about dwellinsg. The 

 scurfy coating on the under surface of the fronds checks evaporation and explains the drought- 

 resisting qualities of the plant. A mat of the plants collected on December 30 showed no signs 

 of withering until January 13, and was not completely withered until 18 daj's later. On April 



