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II. On the Development of the Ovule in Orchis Morio, Linn. 

 By Arthur Henfrey, Esq., F.L.S. 8fc. 



Read April 3, 1849. 



In the spring and summer of last year I made many observations on the young ovules 

 of various plants, with the view of testing the various doctrines on this subject, which 

 had acquired new interest from the recent researches of Amici, Mohl and others. Only 

 one series of my investigations attained anything like completeness ; but in Orchis Morio 

 I believe that I have seen and can confirm all that the above-mentioned observers have 

 described ; and I now present my results to the Linnean Society, partly because I believe 

 that in the present state of the question all evidence derived from careful observation is of 

 some value, and partly because I have succeeded in obtaining a more complete series of 

 figures illustrating the successive conditions of the ovule than has yet been published ; 

 Mohl, who gives the most complete account of the development in Orchis Morio, having 

 given no drawings. The following account is drawn up from my notes made during the 

 observations, principally in the month of May 1848. 



May 3rd. In the ovaries of flowers which had just opened, and were without signs of 

 pollen upon the stigmatic surface, the ovules, about -^oth of an inch long, were just 

 curving over toward the anatropous position; in some the axis of the nucleus formed 

 nearly a right angle with the funiculus (Tab. II. figs. 4 & 5). The nucleus projected 

 beyond the cells, forming the single coat of the ovule, and consisted of a large central cell 

 (the embryo-sac), enclosed by a layer of very delicate cells of small size, constituting a 

 proper coat of the nucleus. 



May 9th. The ovules of fully expanded flowers were not much altered, except in the 

 much clearer definition of the walls of the cells. The embryo-sac was filled with a clear, 

 colourless fluid, in which floated minute black atoms, scarcely large enough to deserve 

 the name of granules. In some flowers the stigmas were smeared with pollen, but often 

 from the anthers of other flowers, their own being still closed. These pollen masses sent 

 down numerous tubes, which differed much from any of the cells of the tissue in which 

 they were engaged. The pollen-tubes were always about Toooth of an inch in diameter, 

 at most one-fourth of the size of the smallest of the surrounding cells, which were also 

 short and often irregular in form, while the pollen-tubes always appeared as long, slender 

 filaments. 



May 13th. The flowers withered and the stigmas covered with pollen. A dense bundle 

 of tubes lay in the midst of the lax tissue of the canal leading to the cavity of the ovary. 

 The ovules were considerably advanced, some being quite anatropous (fig. 6), others three- 

 fourths reversed ; those quite anatropous were about xoo tn of an mcn in length. The two 

 coats of the ovule (tegmen and testa) were now distinctly evident ; the length of the testa 



