CHAP. IX. SELF-STERILE PLANTS. 331 



species of Oncidium and of Maxillaria cultivated in a 

 hothouse in Edinburgh were quite sterile with their 

 own pollen; and Fritz Muller found this to be the 

 case with a large number of Orchidaceous genera 

 growing in their native home of South Brazil.* He 

 also discovered that the pollen-masses of some orchids 

 acted on their own stigmas like a poison; and it 

 appears that Gartner formerly observed indications of 

 this extraordinary fact in the case of some other 

 plants. 



Fritz Muller also states that a species of Bignonia 

 and Tabermemontana echinata are both sterile with 

 their own pollen in their native country of Brazil, f 

 Several Amaryllidaceous and Liliaceous plants are in 

 the same predicament. Hildebrand observed with care 

 Corydalis eava, and found it completely self-sterile ; t 

 but according to Caspary a few self-fertilised seeds 

 are occasionally produced : Corydalis halleri is only 

 slightly self-sterile, and G. intermedia not at all so. 

 In another Fumariaceous genus, Hypecoum, Hildebrand 

 observed Q that H, grandiflorum was highly self-sterile, 

 whilst H.procumbens was fairly self -fertile. Thuribergia 

 alata kept by me in a warm greenhouse was self-sterile 

 early in the season, but at a later period produced 

 many spontaneously self-fertilised fruits. So it was 

 with Papaver vagum : another species, P. alpinum, was 

 found by Professor H. Hoffmann to be quite self- 

 sterile excepting on one occasion ;!" whilst P. somni- 

 ferum has been with me always completely self-fertile. 



Eschscholtzia calif ornica. This species deserves a 

 fuller consideration. A plant cultivated by Fritz 



* ' Bot. Zeitung,' 1868, p. 114. 'Bot. Zeitung,' June 27, 1873. 



t Ibid. 1868, p. 626, and 1870, || Jahrb. fur wiss. Botanik,' 



p. 274. B. viL p. 464. 



\ ' Report of the International t ' Zur Speciesfrago,' 1875, 



Hort. Congress,' 1866. p. 47. 



