116 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



all of which were infected with the Ustilago violacea. Of these 

 five were male plants and did not produce a single seed-vessel. 

 The other has produced female flowers only, but their sexuality 

 has not been equally marked. When it first began to produce 

 flowers it was evident from their external shape that they each 

 contained an ovary. Upon closer examination, however, anthers 

 were found in each flower filled with the Ustilago spores. The 

 stigmata of these flowers were, if not absent, at least reduced 

 to mere points a millimetre or two at most in length on the top 

 of the ovaries. After a time flowers were found with smutted 

 anthers, but longer and better developed stigmata. Towards 

 autumn some few of the flowers were found without stamens, 

 but with well- developed stigmata, and eventually ripe capsules 

 were developed with perfect seeds. From previous experiment 

 I have found that seeds thus produced by an affected plant, 

 although they are few in number, yet when sown gave rise 

 to infected plants. It would thus appear that the fungus has 

 a very potent influence upon the reproductive organs of the 

 host-plant, and although it is spore-producing, hyphae are con- 

 fined to the anthers, yet it does influence the development of the 

 stigmata and the production of seed. 



Barley Smut.— Herewith are sent two specimens of Barley 

 Smut {Ustilago segetum). From the observations of Mr. J. L. 

 Jensen, which he communicated to me last year, he informed me 

 that he had reason to believe on biological grounds that there were 

 at least two distinct species of Ustilago affecting Barley — speci- 

 mens of which he was kind enough to send me. The commoner he 

 calls U. nuda, because the spores are almost naked, and they are 

 soon dispersed by the wind and weather, leaving only the bare 

 rachis of the Barley. The other, much less common, U. tecta, has 

 its spores enclosed in a membranous capsule. They form, more- 

 over, much more compact masses and resist the disintegrating 

 influences of the weather for a much longer period (see Plowright, 

 Brit. Ured. and Ustilag. p. 274). The two species also differ in 

 size and colour and their spores. 



The same observer has arrived at the conclusion, on biological 

 grounds, that the smuts of Wheat, of Barley, and of Oats are 

 distinct species and incapable of infecting other than their 

 proper host-plants — that is to say, the smut of Oats will not 

 affect Barley or Wheat, and vice versa. The biology of the smuts 



