iqiq] , CURRENT LITERATURE 375 



Phoradcndron growing in the Arizona deserts upon various hosts, such as 

 species of Acacia, Querciis, Fraxinus, and Popiilus, that the osmotic concen- 

 tration of the tissue flmds of the parasite is generally greater than that of the 

 host. The concentration of the fluids of such parasites in this semidesert region 

 is also greater than and usually about twice as great as that of similar plants 

 found in the mountain rain-forests of Jamaica. These results quite agree 

 with our expectations, but in a further paper the same investigator" clearly 

 demonstrates the errors that would be involved in generalizing broadly on 

 insufficient data. 



The later investigations have to do with the tissue fluids of epiphytic 

 Bromeliaceae, Orchidaceae, Piperaceae, and Gesneraceae, and these are shown 

 to possess a decidedly lower concentration than those from terrestrial vegeta- 

 tion. In the mountain rain-forests of Jamaica the epiphytes show 37-60 per 

 cent of the concentration commonly found in herbaceous terrestrial vegetation 

 and 28-45 P^r cent of the concentration characteristic of ligneous soil plants. 

 The epiphytes of the Jamaican rain-forests show lower concentrations than 

 related plants of the same habit growing in the subtropical forests of Florida. 

 The exactness of the data and quantitative character of the comparisons make 

 these investigations important, and lead us to look forward for the further 

 results promised in the study of parasitism by quantitative methods. — Geo. 

 D. Fuller. 



Bennettitales. — Two cones of the Bennettitales from the British Cre- 

 taceous, one of them a new species, have just been described by Stopes." 

 The first and most important is the one upon which she has founded the new 

 species B. albianus, the specific name referring to the strata in which the 

 specimen was found. Only a small piece of a single cone was found, but it was 

 very well preserved. After a study of the topography, the entire fragment was 

 cut, yielding 2 longitudinal and 5 transverse sections, the latter passing through 

 the seeds and the former through their stalks. The most striking feature of 

 the cone is its large size, not less than 70 mm. in diameter and probably more. 

 The seeds are innumerable, as many as 600 showing in a single transverse 

 section of the fragment. The seeds are 5-6 mm. long and i . 2 mm. in diameter, 

 thus contrasting with the more or less ovoid seeds already described. The 

 interseminal scales are fused around the apex of the seed. The embryo has 2 

 cotyledons and a rather massive hypocotyl and radicle. 



The other specimen, B. maxinms, was described from superficial characters 

 by Caiiruthers in 1870. The present study shows that the vascular axis is 

 very small for such a large plant and the cones are bisporangiate, the first 

 petrified bisporangiate cones which have been found in England. The cones 



" Harris J. Arthur, On the osmotic concentration of the tissue fluids of 

 phanerogamic epiphytes. Amer. Jour. Bot. 5:490-506. 1918. 



" Stores, Marie C, New Bennettitean cones from the British Cretaceous. 

 Phil. Trans. Roy. Soc. London 208:389-440. pis. ig-24. 1918. 



