ECONOMIC WOODS OF THE UNITED STATES 



139 



transversely and arranged in a vertical series like the rungs of a 

 ladder. This scalariform pitting is characteristic of the vessels in 

 Magnolia, is common in Liriodendron and Nyssa, less so in Liqui- 

 dambar, Ilex and Platanus, and of sporadic occurrence in Castanea, 

 Castanopsis, Quercus, and some others. Since radial grouping is 

 the most common, the pitted surfaces usually appear to better 

 advantage in tangential than in radial sections. 



Pits between vessels and ray cells are simple on the ray side 

 but may be bordered, simple, or transitional on the other. These 



TABLE X 



Nature of Pitting of Vessel W.yll where ix Contact with Ray 



Parenchyma 



Family 



Aceraceae 



Anacardiacese 



Anonaceae 



Aquifoliacea? 



Araliacese 



Betulacese * 



Bignoniacese 



Boraginaceee 



Burseraceee 



Canellacese 



Capparidacese 



Caprifoliacese 



Celastracese 



Cornacese 



Cyrillacese 



Ebenacese 



Ericaceae 



Euphorbiaceae 



Fagacese 



Hamamelidaceae . . . . 

 Hippocastanaceae. . . 



Juglandacese 



Koeberliniaceae 



Lauraceae 



Leguminosae t 



Leitneriaceae 



Magnoliaceae 



Bor- 

 dered 



X 



X 



X 



X- 



X 



X 



X 



X- 



X 



X 



X 



X 



X 



X- 



X 

 X 



Simple 



-X 



-X 

 X 



X 



-X 



-X 



■X 



X 



-X 



X 

 -X 



Family 



Meliaceae 



Moraceae 



Myricaceae 



Myrsinaceae. . . . 



Myrtaceae 



Nyctaginaceae . 



Oleaceae 



Platanaceae. . . . 

 Polygonaceae. . . 

 Rhamnaceae. . . 

 Rhizophoraceae 



Rosaceae 



Rubiacese 



Rutacese 



Salicaceae 



Sapindaceae. . . . 



Sapotaceae 



Simarubaceae. . 

 Sterculiaceae. . . 



Styraceae 



Symplocaceae . . 



Theaceae 



Tiliaceae 



Ulmaceae 



Verbenaceae . . . 

 Zygophyllaceae 



Bor- 

 dered 



X 



X- 



X 



X 



X- 



X 



X 



X 



X 



X 



X- 



X 



X 



X- 



X 



X 



X- 



X 



X 



X 



X 



X 



X 



X 



X 



Simple 



X 

 X 



X 

 X 



* In Betula and Alnus the pits are bordered; in Carpinus, Corylus, and Ostrya 

 simple pits predcwainate. 



t In Robinia the pits are predominately simple. 



