THE PLANT WORLD. 151 



more convenient to put the second paper on the specimen as they are 

 put in the driers. Also for convenience the specimens should always 

 be kept right side up through all the operations, that is the sheet with 

 the tield number should be beneath the specimen, and each bundle of 

 driers should be labelled with the date when the plants were put in, 

 and each day's collection kept in a separate bundle. If the collector 

 is not putting all his time in on this work the method would be some- 

 what modified. The greatest amount of drudgery connected with this 

 work is the drying of the driers. They should be spread out in the 

 sun until they are thoroughly dry and gathered in while hot. They 

 retain the heat, and are thus prevented from absorbing moisture from 

 the atmosphere. This task, however, can often be relegated to a 

 cheap boy. While collecting in south Florida this summer, it being 

 the rainy season, I was obliged to exercise great care in this part of 

 the work. I could not trust help I was able to obtain. On account 

 of sudden showers it was necessary to stand right by the papers until 

 dry, but twenty minutes of bright sunshine on single layers was suffi- 

 cient. With the field press the collector is able to make extended trips 

 on bicycle or by rail, as the plants will keep for 48 hours if carefully 

 packed, and can if convenient be sent to the central station by express 

 where they can be cared for by an associate. 



Large fruits should be air dried if necessary, and preserved in 

 sacks. 



The above remarks apply to the collection of flowering plants and 

 ferns. Special methods are necessary for the collection of the lower 

 crj'^ptogams. 



Manhattan, Kansas, 



NUMBER OF PLANTS KNOWN TO SCIENCE. 



IN an early number of The Plant World we presented the statistics 

 then available as to the number of plants in the world. The fol- 

 lowing estimate is given by Professor S. H. Vines, in his address 

 as vice-president of the botanical section of the British Association for 

 the Advancement of Science: 



Species of Phanerogams indicated in Bentham and Hooker's 

 Oenera Plantaruin. 



