STANDLEY TREES AND SHRUBS OF MEXICO. 843 



9. ZUELANIA A. Rich, in Sngra, Hist. Cuba 10: 33. 1845. 

 The two other species of the genus are West Indian. 



1. Zuelania roussoviae Pittier, Contr. U. S. Nat. Herb. 18: 163. pi. 19. 1916. 



Tamaulipas, San Luis Potosi, Veracruz and Yucatan. Panama, the type col- 

 lected between Rio Grande and Pedro Vidal, Canal Zone. 



Tree, 10 to 25 meters high, the trunk 30 to 50 cm. in diameter, the crown 

 rounded, or sometimes only a shrub ; bark gray and rough ; leaves deciduous, 

 short-petiolate, oblong to oblong-oval, 7 to 12 cm. long, acute or obtuse, rounded 

 at base, pellucid-punctate, becoming glabrate above, beneath densely pilosulous 

 or tomentose ; pedicels in dense lateral clusters, 10 to 14 mm. long ; sepals 5, 

 5 to 7 mm. long, thin, greenish white ; stamens about 32 ; disk with as many 

 staminodia-like appendages as stamens ; fruit a baccate capsule, subglobose, 

 shallowly 3-sulcate, about 3.5 cm. in diameter, yellowish green, opening at the 

 apex by 3 valves; seeds numei'ous. " Volatin " (San Luis Potosf). 



The wood is said to contain an abundant transparent odorless resin. This 

 species is closely related to Z. laetioides A. Rich., of the West Indies, but is 

 distinct in the dense pubescence of the leaves. Pittier states that it is distin- 

 guished " by the obtuse and versatile anthers and the hairy, clavate pseudo- 

 staminodes." The anthers, however, are exactly alike in both species, and in 

 Z. roussoviae the disk appendages are either hairy or glabrous. 



10. CASEARLA. Jacq. Enum. PI. Carib. 4. 1760. 



Shrubs or trees ; leaves alternate, usually distichous, entire or serrate, com- 

 monly pellucid-punctate, persistent or deciduous; flowers perfect, fasciculate, 

 umbellate, or corymbose-paniculate, lateral, small, the pedicels articulate; 

 calyx 4 to 7-lobate, the tube short; petals none; stamens 6 to 25; disk with 

 staminodia-like appendages, these as numerous as the stamens; fruit a dry or 

 fleshy capsule, 3 or 4-valvate ; seeds covered by a fleshy aril. 



The aril surrounding the seeds is edible ; and the fruit is said to have laxa- 

 tive properties. The name " capulincillo " is reported for a Mexican species 

 which has not been identified. 



Stamens 20 to 22; sepals 5 to 7, glabrous 13. C. spiralis. 



Stamens 6 to 15 ; sepals 5. 

 Inflorescence sessile, the pedicels fasciculate. 



Leaves entire or practically so 1. C. sylvestris. 



Leaves serrate or crenate. 



Leaves sharply, closely, and rather finely serrate 2. C. arguta. 



Leaves sinuately and remotely serrate. 

 Leaves lustrous on the lower surface, oblong or narrowly elliptic-oblong, 



mostly 10 to 15 cm. long, glabrous, acuminate 3. C. javitensis. 



Leaves dull beneath, mostly obovate-elliptic, 5 to 10 cm, long, usually 

 pilosulous, obtuse, or very obtusely short-acuminate. 



Leaves rounded or truncate-rounded at base 4. C. platyphylla. 



Leaves mostly cuneate at base. 

 Pubescence of the stems and leaves sparse, appressed, the leaves 



nearly glabrous 5. C. guianensis. 



Pubescence of the stems and leaves dense, spreading, the leaves 



densely velutinous-pilosulous beneath 6. C. obovata. 



Inflorescence pedunculate, corymbose-paniculate. 

 Pedicels glabrous or with a few scattered inconspicuous hairs; outer 



sepals clliate, glabrous on the outer surface 7. C. laevis. 



Pedicels and sepals densely puberulent or pilosulous. 



Leaves glabrous beneath at maturity but often barbate along the costa, 

 when young often pilosulous beneath. 



