MISSOURI BOTANICAL GARDEN. 



section of pecky cypress wood, showing the transition from sound wood 

 to humus compound, after staining with phloroglucin and HC1. : ' g ' 

 primary lamella, unaffected ; ' p ' small masses of humus compound 

 resulting apparently from the transformation of the tertiary lamella ; i ' 

 wood staining yellow, an intermediate stage between the sound wood and 

 the humus compound ; f h ' a thicker layer of humus compound than 

 the one indicated at ' p ' ; ' c ' a still more advanced stage in the humus 

 formation; 'e' the entire cell-wall has been transformed into the 

 humus compound; 'u' piece of cell -wall not yet changed to humus 

 compound. 



Plate 4. 1, Transection of sound wood of Libocedrus decurrens, 

 showing spring and summer wood : * h ' brown hypha with attachment 

 organs ; ' s ' spores often found in the wood cells. 2, Transection of 

 diseased wood of Libocedrus decurrens^ i. e. wood from one of the pockets. 

 The color is the natural color of the wood. The medullary ray is filled 

 with brown humus solution. 3, Block of Taxodium distichum showing 

 pecky hole lined with white fibers, consisting of pure cellulose (XJ) *, 

 Two tracheids from wood surrounding a diseased spot in Taxodium 

 distichum. The tracheids are filled with brown humus compound which 

 has cracked in drying. 



Plate 5. 1, Mycelium from decayed wood of Taxodium distichum, 

 showing the numerous clamp connections. 2, Spores from pecky wood 

 of Libocedrus decurrens. (The line at the top is 10/i.) 3, Portion of a 

 tracheid near diseased area of Taxodium distichum. The pits appear 

 corroded because of a peculiar arrangement of resin globules. (Magni- 

 fication same as fig. 2.) 4, Brown chlamydospores from rotted wood 

 of Taxodium distichum. 5, Brown spores from wood of Taxodium dis- 

 tichum. These are like the ones found in the red cedar. 6, Spores from 

 wood of Quercus alba destroyed by Polyporus sulphureus (from Will- 

 iamsville, Mo. ; magnification same as fig 6) . 7, Spores from wood of 

 Taxodium distichum, resembling Willkomm's Xenodochus ligniperda. 8, 

 Minute bodies, which appear in the humus compound when the latter is 

 slowly dissolved away. Two views are represented (magnification same 

 as fig. 2). 9, Mycelium showing attachment organs: ' a-c ' from wood 

 of Taxodium distichum; ( d-f ' from wood of Libocedrus decurrens. 10, 

 Longisection of pecky cypress wood, showing gradual disintegration of 

 the tracheids : ' a ' normal tracheid filled with humus compound ; * b 

 similar tracheid with colorless mycelium ; ( c ' tracheid with pits looking 

 as if corroded ; ' d tracheids with walls which are beginning to contract ; 

 ' e tracheid in which the walls show spiral cracks; ' f ' and ' g ' tracheids 

 showing final stages in the process of solution. (Magnification same 

 as fig. 1.) 11, Longitudinal section through pecky wood of Libocedrus 

 decurrens : ' a ' normal tracheid ; ' b ' tracheid showing beginning of 

 disintegration, the pits show cracks, some spores are collected near 

 a wall ; f c ' and ' d ' tracheids which have contracted considerably, show- 

 ing cracks in the pits and the wall. (Magnification the same as the pre- 

 ceding figure.) 

 54 



