







/ 



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Chap. VIII. CLEISTOGAMIC FLOWERS. 329 



ers; the latter yield from 18 to 24, whilst the former 

 only from 8 to 10 seeds; these two kinds of flowers 

 are produced simultaneously, whereas in several other 

 members of the family the cleistogamic ones appear 

 only during the hot season. According to Torrey and 

 Gray, the North American species of Helianthemum, 

 when growing in poor soil, produce only cleistogamic 

 flowers. The cleistogamic flowers of Specularia per- 

 foliate, are highly remarkable, as they are closed by a 

 tympanum formed by the rudimentary corolla, and with- 

 out any trace of an opening. The stamens vary from 

 3 to 5 in number, as do the sepals.* The collecting 

 hairs on the pistil, which play so important a part in 

 the fertilisation of the perfect flowers are here quite 

 absent. Sir J. Hooker and Dr. Thomson state f that 

 some of the Indian species of Campanula produce two 

 kinds of flowers ; the smaller ones being borne on longer 

 peduncles with differently formed sepals, and produc- 

 ing a more globose ovary. The flowers are closed by 

 a tympanum like that in Specularia. Some of the plants 

 produce both kinds of flowers, others only one kind; 

 both vield an abundance of seeds. Professor Oliver 

 adds that he has seen flowers on Campanula colorata in 

 an intermediate condition between cleistogamic and per- 

 fect ones. 



The solitary almost sessile cleistogamic flowers pro- 

 duced by Monochoria vaginalis are differently protected 

 from those in any of the previous cases, namely within 

 " a short sack formed of the membranous spathe, with- 

 out any opening or fissure." There is only a single 



*Von Mohl, 'Bot. Zeitung/ of the perfect flower is mostly 



1863, pp. 314 and 323. Dr. Brom- 5-cleft. 



field C Phytologist,' vol. iii. p. t Journal Linn. Soc/ vol. fit. 



530) also remarks that the calyx 1857, p. 7. See also Professor 



of the cleistogamic flowers is Oliver in Nat. Hist. Review/ 



usually only 3-cleft, while that 1862, p. 240. 



