616 JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



Red Gum (Liquidambar styraciflua), Sap Rot, and other Diseases. 



By Hermann von Schrenk (U.S.A. Dep. Agr., Bur. PL hid., Bull. 114, 

 December 1907 ; 8 plates). — The sap-wood of the red gum is destroyed 

 with great rapidity by several sap-rotting fungi. The decay caused by 

 these fungi may be called " sap-rot." They grow most rapidly during 

 the spring and summer months, and enter mainly through the ends of 

 logs piled on the banks of rivers. 



Sap-rot may be prevented by shortening the drying period in the 

 woods, either by hauling logs by rail or by reducing the moisture in the 

 log. This may possibly be accomplished by felling the gum trees without 

 sawing them into logs and leaving them in the forest until the leaves are 

 thoroughly dry. The amount of water evaporated by the leaves before 

 they dry may be sufficient to permit of floating the logs cut from such 

 leaf-seasoned trees. 



The sap-rot may likewise be almost entirely prevented by coating the 

 ends immediately after the logs are cut with hot coal-tar creosote. The 

 cost of this treatment is about 8 cents per 1,000 feet. 



Wherever possible all freshly cut logs, particularly such as are cut 

 during the spring and summer months, should be peeled. 



The heart-wood of the red gum is comparatively resistant against 

 decay. 



Sap-rots similar to those which are found in the red gum are found 

 in the tupedo gum, swamp oak, and maple. 



The fungi responsible for sap-rot in the red gum are chiefly Polyporus 

 adustus, sometimes with Polystictus livesutus and Porta subacida. A 

 few other fungi of minor importance cause decay of the sap-wood of the 

 red gum.— if. C. C. 



Renanthera annamensis. By R. A. Rolfe (Bot. Mag. tab. 8116).— 

 Nat. ord. Orchidaccae ; tribe Vandeae ; Annam. A dwarf epiphyte, 

 8-12 inches high ; flowers yellow spotted with crimson ; lat. sepals 

 spathulate, | inch long ; petals oblong, J inch long. — G. H. 



Rhododendron Delavayi. By W. B. Hemsley (Bot. Mag. tab. 

 8137). — Nat ord. Ericaceae; tribe Bhodoreae ; China. A small tree; 

 leaves 3-6 inches long ; flowers crimson with black spots at base of 

 corolla. — G. H. 



Rhododendron intrieatum. By W. J. Bean (Bot. Mag. tab. 

 8163). — Nat. ord. Ericaceae ; tribe Bhodoreae ; China. Dwarf shrub, 

 4-6 feet high ; leaves J-^ inch long, white beneath ; trusses 5-ilowered ; 

 corolla violet or lilac ; anthers orange- coloured. — G. H. 



Ribes mogollonicum. By S. A. Skan (Bot. Mag. tab. 8120).— 



Nat. ord. Saxifragaceae ; tribe Bibesieac ; S.W. United States. A 

 robust shrub, 10 feet high ; leaves five-lobed ; petals white ; berry 

 purplish or bluish-black. — G. H. 



Rice Cultivation in British Guiana. By Hon. B. Howell Jones 

 (Journ. Imp. Dep. Agr. W.I. 1907, 7). — Returns made to the Board 

 of Agriculture have shown that the acreage under rice had increased 

 from about 6,000 acres in 1900 to about 24,000 acres in 1906.— ill. C. C. 



