346 BOTANICAL GAZETTE [may 



osmotic pressure can exist side by side without those of higher pressure draining 

 those of lower, which, however, they would do as soon as their turgor was relaxed 

 ever so slightly, thus releasing some of the osmotic energy that had previously 

 been expended against the wall. This point has been often overlooked. 



Ursprung'° makes .what he himself properly calls "a small contribution" 

 (which nevertheless fills sixty-odd pages!) to a more extended study of the relation 

 of live cells to the ascent of water in woody plants. His data will be more useful 

 than his interpretation. The experiments, carried on in the forests, embraced 

 five species of g}-mnosperms and fifteen of angiosperms. The axes were killed 

 for greater or less distances at various levels by steam^ and usually others were 

 girdled at the same time. Microscopic examination was made of both dead por- 

 tions and neighboring parts. Ursprung explains the dissimilar behavior of 

 different species on the assumption (and therefore begs the question) that the 

 experimental interference eliminates the vital component of the litting forces, but 

 does not affect the physical; so as the vital factor is greater or less the wilting of 

 the leaves occurs in a few days in some experiments or is delayed to loo m others. 

 His "results" he summarizes thus: '*In all the plants investigated a participa- 

 tion of the living cells in the production of the lifting force is to be assumed." 

 (Is this a result?) *' Water conduction occurs chiefly in the younger layers of the 

 wood." (This has been long known.) ''In all observed plants the cortex must 

 be present in order to make possible the continuance of a sufficient water move- 

 ment; its removal acts injuriously, though not everywhere equally. The signiti- 

 cance of the cortex for the ascent of sap lies probably in its protective function for 

 the periphery of the wood." (This has scarcely been doubted.) "For a sufficient 

 water-movement a small fraction of the conducting tissues suffices, if in the part 

 remaining the wood cells be living." (The if is not a condition proved but 

 assumed.) '*The force component arising from the living cells attains great 

 significance in comparison with the purely physical." {Quod est demonstrandum,) 

 C. R. B. 



Items of taxonomic interest.— C. B. Clarke (Contrib. U. S. Nat. Herb. 

 10:443-471. 1908), before his death, had prepared a synopsis (in Latin) of the 

 Cyperaceae of Costa Rica. This has now been published, with such changes as 

 were necessary, such as translation into English (by E. L. Greexe), rearrange- 

 ment of synonymy, completion of citations, elimination of nomina nuda, etc. A 

 synoptical key to the 19 genera precedes the presentation of the 105 species, 

 large genera are Rynchospora (16), Cyperus (15), Eleocharis (13), and Selena (n), 

 and a single new species is described in each of the following genera: Cyperus, 

 Rj-nchospora, and Carex.— J. J. Smith (Bull. Dept. Agric. Ind. Ne'erland. no. 13- 

 pp. 78. ph. 2. 1907), in the first of a series of papers on the orchids of Java, has 

 described 15 new species and 2 new genera {Silvorchis and Lectmtdra).—^- ^^ 

 (Notizblatt 5: no. 41a. pp. 52. ph. 4. 1908), in connection with an account of the 



1° Ursprung, A., Abtotungs- und Ringelungsversuche an einigen HolzpSanze. 

 Jahrb. Wiss. Bot. 44:287-349. pi. 4. 1907. 



