THE AMERICAN NATURALIST 



[Vol. LIII 



spikelet. As shown in Table I, the spikelets near the top of the panicle 

 are either entirely naked or nearly so, while those spikelets near the 

 base of the panicle tend to be firmly hulled. A similar but less marked 

 relation is to be observed between the spikelets at the tip and base of 

 each whorl. 



In the Fj generation a large number of intermediate forms appear. 

 In addition to the two parental hull types, four intermediate classes 

 were distinguished. These intermediate forms contain all gradations 

 from the plants with perfectly hulled grain to the perfectly naked 

 forms. 



As shown in Table II, the inheritance of the hull characters presents 

 a simple Mendelian relation giving 1 hulled, 2 intermediate, 1 naked. 



Matekial and Methods 



In cGniiectioii with some experiments in oat breeding 

 a number of hybrids between the hulled and hull-less 

 forms have been made. While in these crosses the in- 

 heritance of other characters such as color of glumes, 

 pubescence, awns and the like, are very interesting, the 

 present paper w^ll be confined to the discussion of the 

 inheritance of the hull-less and hulled characteristics. 

 A more complete discussion of the various characters is 

 being prepared for a later publication. 



The authors want to take this opportunity to express 

 their appreciation for the valuable assistance in note- 

 taking and tabulation of results rendered by W. T. Craig 

 and Miss A. M. Atwater. Their work has been of great 

 aid in conducting these experiments. 



The hull-less oat used for the various hybrids was 

 typical of the Avena nuda group and differs from the 

 Avena sativa forms by three important characters: (1) 

 The lemma, or flowering glume, and palet do not clasp 

 the kernel as in other forms, and the kernel is therefore 

 loose, or free, wdthin the hull; (2) The rachilla; of the 

 three to many-grained spikelet are so elongated that 

 the uppermost grains are borne above the empty glumes ; 

 (3) The glumes and the lemmas are similar in texture. 

 The illustration (Fig. 1) will give a fair idea of the par- 



