762 



Journal of Agricultural Research 



Vol. VI, No. 20 



number of plants which produce impermeable seeds. The present 

 author has found that many of the seeds of the species of plants considered 

 in this paper are more readily permeable to water in the region of the 

 chalaza than elsewhere. 



Nobbe and Haenlein (16), Gola (8), Ewart (7), Rees (17), and Guppy 

 (9) have given us a good idea of the distribution among the natural plant 

 families of species which produce impermeable seeds. All agree upon the 

 Leguminosae as far surpassing all other families in this respect. Many 

 other families also contain species which produce impermeable seeds. 



OCCURRENCE OF IMPERMEABLE SEEDS IN CULTIVATED SPECIES 



The peanut (Arachis hypogaea) excepted, probably all commercially 

 important legumes cultivated in the United States produce a greater or 

 less percentage of impermeable seeds. The percentage is small or fails 

 entirely with spring vetch (Vicia sativa L-), some varieties of soybeans 

 (Soja max (L.) Piper), kidney beans (Phaseolus vulgaris L.), Lima beans 

 (Phaseokis lunatus L-), garden peas (Pisum sativum L.), and the newly 

 introduced black bitter vetch (Vicia ervilia (L.) Willd.). 



Table I shows the percentage of impermeable seeds in the commercial 

 samples of a number of small-seeded legumes which have been tested by 

 the Seed Laboratory during the six years 1904 to 1909. 



Table I. — Percentages of impermeable seeds in small-seeded legumes tested during the 



years IQ04 to IQOQ 



1 Only two years' tests. 



2 Only one year's tests. 



Recent investigations by the author (10) show that the first four 

 species of plants in Table I produce very much higher percentages of 

 impermeable seeds than are indicated and that many of the seed coats 

 become permeable to water during the operation of hulling the seeds. 



Important nonleguminous plants which produce impermeable seeds are 

 okra (Hibiscus esculentus L.) and hollyhock (Althea rosea (L.) Cav.), both 



