LONGEVITY OF SUBMERGED SEEDS 



335 



Agrimonia hirsula 

 Asclepias Syriaca 

 Chenopodium album 

 Circaca Lutctiana 

 Geum Carolinianum 

 Hieracium sp. 

 Juncus bufonius 

 J uncus tenuis 

 Lappa minor 

 Muhlenbergia diffusa 

 Phri/nin Icptnstachya 



Plantago Rugelvi 

 Polygonum arifolium 

 Polygonum Virginianum 

 Rhus glabra 

 Sanicula Marylandica 

 Sium cicuiaefolium 

 Solidago rugosa 

 Sparganiinn androcladum 

 Unifolium Canadense 

 Verbena urlicaefolia 

 Washinglonia longistylis 



One lot of seeds of each species was deposited on a layei- of 

 soil in each of six large glass jars on December 13, 1905, and placed 

 in a dark room in the basement of the laboratory, where there 

 is relatively little fluctuation in temperature. The water was 

 replenished, from time to time so that submergence was continu- 

 ous. During the last year of the experiment the jars were sub- 

 jected to diffuse light during the day, owing to the cutting of an 

 open doorway leading into a skylighted cave-room. 



The first of these jars was removed to the greenhouse and 

 drained July 1, 1907, after a submergence of 565 'days or 18^ 

 months. In several days numerous seedlings appeared, not all 

 of which w^ere identified before my departure for California in 

 September, but the following were recognized: 



Cyperus spp. 

 Juncus tenuis 

 Muhlenbergia diffusa 



Plantago Hiigclii 

 Si urn cicutaej'oliu m 

 Verbena urlicaefolia 



A second jar was drained 11 months later, May 31, 1908. 

 Among the large number of seedlings which appeared in a few 

 days, occurred the following species. With the exception of 

 Chenopodium album and Lapp^ minor, all appeared in consider- 

 able numbers. 



Chenopodium album 

 Lappa minor 

 Muhlenbergia diffusa 



Plantago Rugelii 

 Sium cicuitaefolia 

 Verbena urlicaefolia 



On March 7, 1910, the soil in a third jar was laid bare, and in 

 five days numerous seeds were seen germinating after a continu- 



