424 PLANTS, SEEDS, AND CURRENTS 



for October 14, 1909, those for the seeds being supplied by Mr. 

 Lloyd Praeger's report in the Clare Island Survey (Proc. Roy. Irish 

 Acad., XXXI., 1911). All the plants indicated under the various 

 headings are with the exception of Typha latifolia represented in 

 the present flora of the Azores. 



Table illustrating the Falling Rates op Spores and Seeds and the Initial 

 Elevation that they would require if transported by the Wind from 

 the Uplands op Portugal to the Azores, a Distance op about 800 Miles. 

 (See above por explanatory remarks.) 





Falling Rate. 



Minimum Initial Elevation with 

 favourable wind blowing fifty 

 miles an hour. (Elevations 

 approximate.) 



Hymenomycetes (mush- 

 rooms in a general 

 sense). 



- 3 to 6 mm. per second 

 (B-). 



oi to iiou ieet. 



Lycoperdon (puff-ball). 



- 46 mm. per second 

 (Z. and M.). 



86 feet. 



Polytrichum. 



2-28 mm. per second 

 (Z. and M.). 



430 feet. 



Lycopodium. 



17 '7 mm. per second 

 (Z. and M.). 



3300 feet. 



Typha latifolia (plumed 

 seed). 



12 feet in 34 seconds. 



20,000 feet or 3i miles. 



Epilobium (plumed seed). 



12 feet in 20 seconds. 



35,000 feet or 5| miles. 



Sonchus oleraceus, 

 Senecio vulgaris 

 (both plumed seeds). 



12 feet in 12-7 and 12-8 

 seconds. 



54,000 feet or nearly 9 

 miles. 



Habenaria (orchid). 



12 feet in 12 seconds. 



58,000 feet or 9J miles. 



Carduus pycnocephalus 

 (plumed seed). 



12 feet in 5 seconds. 



138,000 feet or 22J miles. 



Sagina procumbens. 



12 feet in 3-5 seconds. 



197,000 feet or 32 miles. 



Juncus. 



12 feet in 3 seconds. 



230,000 feet or 38 miles. 



We may infer from the data just given, assuming that the argument 

 is valid, that whilst there would be no difficulty in postulating the 

 requisite initial uplift for cryptogamic spores we could not do so 

 for the seeds of J uncus and Sagina procumbens, however small they 

 may be. But the difficulty is not so great as it at first seems for those 

 seeds that require an initial elevation of from six to ten miles, as 

 in the case of Epilobium, Senecio, Sonchus, and Habenaria, Typha 

 being excluded as it is not found in the Azores. If the wind blew 

 with the extreme maximum force of a hurricane, say, at 100 miles 

 an hour, the lift requisite for the seeds would be halved and the 

 passage to the islands would be accomplished in eight hours. Under 



