ABSTRACTS OF LECTURES. 65 



y^anuary 20th. — Ancient Egypt. 

 By R. C. Clephan, F.S.A. 



Printed in extcnso in the present volume, pp. 10-34. 



Febrtiary lOth. — Orchids. 

 By J. BiDGOOD, B.Sc. 



The orchids are the most numerous amongst monocoty- 

 ledons, it being computed that there are over 8,000 species, of 

 which 36 are reputed as native in the British Islands. Most of 

 them grow in the warmer and moister portions of the world, 

 although one, Calypso boreale, has been found as far north as 

 latitude 68°. Their structure is unique. The floral envelope 

 consists of two whorls of three segments each, one of the three 

 being always different, and sometimes very different from the 

 other two. The ovary is single celled, or imperfectly three- 

 celled, and the stamens are sessile on a prolongation of the 

 ovary. 



Some are terrestrial, their mode of nutrition being that of 

 most other green plants ; a few are terrestrial, green, but 

 saprophytic, whilst a few are not green and wholly saprophytic. 

 Most of the exotic species are epiphytes, growing on living 

 plants, but not feeding on them. We have but one epiphyte, 

 Malaxis paludosa, a bog plant. The epiphytes are provided 

 with clasping roots to hold them in position, and aerial roots 

 which absorb water and other substances from the air. They 

 have always thickened stems known as pseudobulbs, and 

 both aerial woolly roots and pseudobulbs are useful in tiding 

 them over the hot dry seasons which they must experience in 

 their native homes. 



They are usually cross-fertilised, the structure of the 

 flowers frequently preventing self-fertilisation, although quite 

 a large number are regularly self-fertilised. The agents of 

 pollination are usually flying insects, although birds, snails, 

 slugs, and other crawlers carry out the process in many 

 instances, being led to visit the flowers by their bright colours, 

 perfume, and nectar which is produced in nearly all of them. 



