October, igi6.] 



THE ORCHID WORLD. 



Fig". 13. Fragment of Iransverse section of stem of Cattleya inter- 

 media, enlarged 2C0 diameters. 



1. epidermis of one layer of thick-walled cells overlain by thickened 

 cuticle; 2, hypodermis of large thick-w ailed cells; 3. fundamental 

 tissue of soft thin-walled cells ; 4, a vascular bundle. 



Fig. 14. Longitudinal section of a fragmjnt of stem of Cattleya 

 intermedia, from epidermis through a fibro-vascular bundle, x 200. 



1, cuticle epidermal and hypod rmal cells; 2, fundamental tissue of 

 soft thin-walled cclU ; 3, a row of short thick-walled cells with 

 granular protoplasmic contents ; 4. woody fibre ; 5, two contiguous 

 spiral vessels; 6, parenchyma. 



Orchids is noteworthy, and shows that the 

 roots m these cases perfornn to some extent 

 the same functions as the leaves. Ordinnry 

 roots contain no chlorophyll. 



Fig. 15. A, transverse, B. longitudinal section ot root of Odonto- 

 Klossuni crispiini horizontally placed. 



1, epidermis; 2. cortical tissue of thin-walled cells : 3, endodermis. 

 consisting of layer of cells with thickened walls surroiindinp ; 4. 

 the fundamental tissue of the root; 5, \ascular bundles of the axial 

 cylinder, forming the hard-wood tissue of the root ; 6. the pith ; 7, 

 bast cells. 



Fig. 16. Fragment of transverse section of root of Cypripedium 

 insigne, from the circumference to the centre, enlarged 25 diameters. 



f, epidermis with root hairs ; 2, cortical tissue : 3, endodermis ; "1, 

 fundamental or soft tissue of root ; 5, axial cylinder of vascular 

 bundles surrounding a central pith. 



With ligneous parenchyma and parenchyma- 

 tous tissue composed of thin-walled cells. 

 The details of the minute structure of the 

 roots of Orchids are well shown m the 

 accompanying sections selected from genera 

 in different Tribes, and which may be regarded 

 as fairly representative types of each. The 

 presence of chlorophyll in the aerial roots of 



PoUinia of Cattleya labiata. 

 A, side ; B, front view. 



