Notes and Enquiries on dioecious Plants. 301 



stems that bear flowers are terminated by a bracteated peduncle, 

 upon whose tip the flowers, usually two, are disposed. Dimi- 

 nutive in magnitude as is L. tidentata, it is not less interesting in 

 structure than larger forms : a proof of this may be found in the 

 description, and seven figures of magnified views of it, produced 

 in illustration of this point, in the Bot. Beg., May. 



Art. VIII. Notes and Enquiries on certain Species of Plants 'which 

 have their Sexes dioecious. By John Denson. 



It is stated that all species of plants have sexes, except the species of the 

 kinds which Linnaeus referred to his class Cryptogamia. The sexes in plants 

 are analogous to the sexes in animals in their subservience to the multipli- 

 cation of the individuals of each of the species to which they and the indivi- 

 duals belong. The offices of the sexes are, in plants, exercised in the stamens 

 for the male sex, and pistils for the female sex. Fig. 35. represents a sta- 

 men, of which a is the filament, b the anther, c the pollen. 

 The filament is not an essential part of a stamen, and, in 

 some species of plants, is so diminutive as to be inobvious. 

 Fig. 36. represents a pistil, of which a is the ovarium, 

 or germen, which includes the ovules or rudiments of seeds ; 

 b the style, c the stigma. The style is not an essential 

 part of a pistil, and, in some species of plants, is wholly 

 absent. The function of these two kinds of organs is 

 this : pollen {Jig. 35. c) is shed from the anther {Jig. 35. b) ; and, from 

 the pollen, an essential property or properties is acquired to the ovules 

 within the ovarium : and this by the intervention of the stigma and the 

 style, in species of plants which have these. Not any ovule that has not been 

 imbued with the essential property or properties from the pollen can become 

 a seed capable of germinating to the production of a plant. 



In plants, the sexes are comported in four modes : — I. Both sexes in the 

 same flower in every flower borne by the same species of plant. 2. Each sex 

 separate in distinct flowers upon every plant of the same species. 3. One 

 sex in every flower borne by one plant, the other sex in every flower borne 

 by anotfier plant; the two plants included in one species, which species 

 they constitute. 4. The sexes separate in distinct flowers, and together in other 

 flowers, upon one plant, constituting a species, or upon two plants con- 

 stituting a species. The sexes, when comported in the 1st mode, are termed 

 hermaphrodite; in the 2d, monoecious; in the 3d, dioecious; in the 4th, poly- 

 gamous. 



Certain of the species of plants which have their sexes dioecious are the 

 subject of the following notes, whose foremost object may be expressed in 

 questions like the following : — Of how many of the dioecious-sexed species of 

 plants, exotic to Britain, yet cultivated in it, are there both sexes possessed ? 

 What are these species ? Where are living plants of their sexes ? Which 

 are the species of which but one sex is possessed ? Which of the two sexes 

 is this one ? Where is a living plant of it ? The object of the enquiry which 

 these questions include is to obtain the information for which they ask. This 

 would have been, it may be deemed, more manifest, and the mode as likely 

 to be effective of the result desired, had questions equivalent to the above 

 been simply proposed, and a list presented with them of the names of the 

 species of plants which are subject to these questions. I hope, in apology, 

 that the details, and the attempt to be botanical, into which I have allowed 

 myself to digress, will not repress the contributions of any of those of my 

 practical brethren who may be in any degree able to contribute to elucidate 



