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XXX. Observations on the Structure and Development of the Organs of 

 Pilularia globulifera. In a Letter to R. H. Solly, Esq., F.R.S. 8f L.S. 

 By William Valentine, Esq., F.L.S. 



Read March 19th, 1839. 



From various causes, particularly removing from North Wales to this 

 place, I have not had it in my power at an earlier period to reduce my 

 observations into proper form for your perusal. A visit to St. David's would 

 amply repay a botanist, as, from what I saw, I conceive it to be a rich 

 locality, and, as far as I know, not yet explored ; but having on the second 

 day of my arrival gathered Pilularia globulifera for the first time in my life, 

 I determined to bestow all the time I could command on its examination, 

 and therefore I did not collect many species. I must beg to remark, that as I 

 only know what preceding observers have discovered of the structure of Pilu- 

 laria through Lindley's Introduction to the Natural System, and Hooker's 

 British Flora, it is possible that the greater part of my observations may be 

 already known ; and therefore I leave you to judge whether this letter con- 

 tains sufficient novelty to justify its publication. 



The involucrum (Tab. XXXIV. fig. 2.) of Pilularia globulifera contains two 

 kinds of bodies, which, however, occupy distinct sacs : one kind (Tab. XXXV. 

 fig. 36.) are round, very numerous, and minute, not larger than the 460th part 

 of an inch ; they are found principally in the upper part of the involucrum, and 

 are about forty in each sac : the other kind (Tab. XXXIV. fig. 3.) are of an 

 oblong pyriform shape, a little constricted near the middle, with a conical 

 projection at one extremity, and are much less numerous, about sixty, and 

 occur singly in each sac ; they are about the 80th of an inch broad, and have 

 the power of germination, which the former kind do not appear to possess. 

 Both kinds are loose in their sacs, and have an opake, pure white, minutely 

 granular, testaceous covering, and are imbedded in a kind of gelatine, which 



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