74 



GENERAL in=:VlK\y OF THE OROHIDE.E. 



Fig. 23. A, trausvt'r.Sf, B, Imigitudinal section of root of OdoiitO(jlossum crUpuni horizontally placcil. 



1, epidermis ; 2, cortical tissue of tliin-walled cills ; 3, endodermis, consisting of a layer of cells with thickened 



walls surrounding ; 4, the fundamental tissue of the root; 5, vascular bundles of the axial cylinder, forming 



the hard-wood tissue of the root ; 0, the pith ; 7, bast cells. 



FERTILISATION. 



One great inducement to the cultivation of epiphytal orchids is 

 the length of time the flowers of most of the species continue in i 

 perfection after expansion. It is generally known that with some 

 exceptions to be presently noticed, the cause of this duration is i 

 owing to their never becoming fertilised unless by some external 

 agency ; they thence retain their attractiveness day after day 

 awaiting the event for which they were created, but which under 

 the circumstances of their environment rarely takes place unless 

 artificially effected by the hand of the hybridist, or if, perchance, ' 

 a bee attracted by the scent or colour of the flowers, enters the i 

 house in quest of honey, and alighting on the labellum makes its 

 way to the nectary, removes the pollinia from one flower and 

 deposits them on the stigma of another. The annexed figure repre- j 

 sents a bee caught in our Cattleya house a few years ago, when | 



a goodly number of plants of Gattlef/a Mossice \ 

 were in bloom and also several plants of 

 OJontoglossum citrosmum ; the pollinia on the | 

 head of the insect are those of the Odonto- I 

 glossum ; on the thorax between the wings j 

 are those of the Cattleya.* 



A plant of Catllejia Mossiw in a garden near Halifax is reported in the Oardcners' Chronicle 

 of 18.55, p. 614, to have borne three capsules whose fertilisation wa.s ascribed to some bees ' 

 that were observed flying abont in the greenhonse in which the plant was suspended. The , 

 flowers of Cattleya Mossiw, as is well knov/n, are delightfully fragrant, and honey is excreted 

 from the base of the column. 



