17G 



ORCHIDACE^. 



[Endogens. 



the pollen masses are secured when any adliesion between them and the stigma takes 

 place. Hence such a plant would appear to be monandix)us ; it will be seen, however, 

 in Gingerworts and Marants, the only other monandrous Orders of Endogens, that, 

 while only one perfect stamen is developed, two others exist in a rudimentary state ; 

 so that the ternary number prevalent in Monocotyledons is not departed from. So it is 

 in Orchids : the column does not consist of a single filament cohermg with a style, 

 but of tlu-ee filaments firmly gi-own together, the central of which is antheriferous, and 

 the lateral sterile. This is proved by the frequent presence of callosities, or processes 

 in the place of the sterile stamens ; by imperfectly-formed anthers occasionally appear- 

 int' at the side of the perfect one ; and, if any further evidence were wanted, by mon- 

 sters, in which a regular stinicture is exchanged for the ordmary iii-egularity. Such 

 an instance in Orchis latifoUa is described by Achille Richard, m the Memoires de la 

 Soc. cVHkt. Nat. of Paris, m which the flowers were perfectly triandrous, with no trace 

 of u-regularity m any part of the floral envelopes ; and other cases of a similar nature 

 are bv no means uncommon, and have been occasionally mentioned. 



Orchids are remarkable for the unusual figure of their irregular flowers, which 

 sometimes represent an mseet, sometimes a helmet with the -vasor up, and are so 

 various m form that there is scarcely a common reptile or insect to which some 

 1 2 3 4 



of them have not been hkened. Their 

 flowers, however, ^^•ill all be found 

 to consist of three outer pieces be- 

 longing to the calyx, and three inner 

 belonging to the corolla ; and all de- 

 parture from this number, six, depends 

 upon the cohesion of contiguous parts: 

 ^\lth the solitary exception of Mono- 

 meria,in ^^ Inch the lateral petals are en- 

 tirel\ abortive ; of certain Bolbophylla, 

 such as B. bracteolatum, which have 

 an additional scale on the outside of 

 the petals; and of the calyculate genera, 

 such as Epistephium, in which the 

 external calyx above alluded to makes 

 its appearance in the foi'm of an exter- 

 nal cup. Sometimes two of the sepals 

 cohere into one, as in certain species 

 of Oncidium, and then the calyx has 

 the appearance of consisting of but two 

 sepals ; sometimes the lateral petals are connate with the column, as in Gongora and 

 and Lepanthes, and then the column appears furnished with two wings. In neai'ly the 

 whole Order the odd petal, called the lip, arises from the base of the column, and is 

 opposite it ; but in the Cape genus Pterygodium, the lip sometimes grows from the 

 apex of the column, and sometimes is stalked and turned completely over between the 

 fork of the inverted anther, and thus seems to belong to the back of the column . Nor 

 is the anther less subject to modification, although constant to its place : sometimes it 

 stands erect, the Une of dehiscence of its lobes being turned towards the lip ; sometimes 

 it is turned upside dowTi, so that its back regards the Up ; often it is prone upon the 

 apex of the column, where a niche is excavated for its reception. The pollen is not 



cxx. 



Fig. CXX. 1. Angrsecum eburneum 

 5. Caladenia ; 6. Disa spathiilata. 



2. Diuris; 3. Drj'moda picta; 4. Oberonia Oriffithiana ; 



