April, 1912.] Key to the Fruits of the Genera of Trees. 509 



35. Seed without wings or hairs. 39. 



36. Seed with a tuft of hairs, capsule small. 37. 



36. Seed with wings, the wings sometimes with a fringe of 



long hairs. 38. 



37. Capsvtle with a little cup at the base. Populus. 



37. No cup at the base of the capsule but 1 or 2 little glands 



may be present. Salix. 



38. Capsule very long, wings of seed with a fringe of hairs. 



Catalpa. 



38. Capsule short, wing of seed without hairs. Paulo wnia. 



39. Seeds very large, 3^-2 in. in diameter. 40. 



39. Seeds much less than 3^2 in- in diameter. 41. 



40. Seed smooth with a large light spot at one end, without 



ridges or angles. Aesculus. 



40. Seed with two or inore vertical ridges, without a special light 



spot — a nut in an enclosing husk which may be mistaken 

 for a capsule. Hicoria. 



41. Seeds with a fleshy, scarlet aril, capsule lobed. Euonymus. 



41. Seeds without an aril. 42. 



42. Seeds 1 or 2, capsule not bladdery. 43. 



42. Seeds several to many. 44. 



43. Capsules small without a cup at the base. Xanthoxylum. 



43. Capsule woody, 3^2 in. long, with a prominent cup at the 



base; seeds 2, oblong. Hamamelis. 



44. Capsule triocular, large, bladdery. 45. 



44. Capsule with 5 — ^many cavities, small. 40. 



45. Capsule 3-lobed at the tip, with 3 styles, usually widest at 



the middle or toward the outer end. Staphylea. 



45. Capsule with a long, acute tip, with a single style, widest 



below the middle. Koelreuteria. 



46. Capsules mostly woody, oblong, ]3ubcrulent; in corymbose 



or umbellate clusters. Rhododendron. 

 46. Capsules depressed-globose, somewhat 5-lobed; in corjrmbose 

 or umbellate clusters. Kalmia. 



46. Capsules ovoid-]jyraniidal, 5-angled; in large panicled 



racemes. Oxydendrum. 



47. Fruit a dry diTipe, or diiipe-like; exocarp softer than the bony 



endocarp. 48. 



47. Fi"uit a nut or achene, the pericarp not in 2 layers; often 



partly or completely enclosed in a cup or husk. 49. 



48. Fruit globose, 3<£ in. or more in diameter, on winged peduncles 



Tilia. 

 48. Fruit obliquely ovoid, compressed, ridged on the back and 



covered with prominent soft processes. Planera. 

 48. Fruit subglobose, nearly symmetrical, | in. long, pubescent 



or if not the stone striate. Rhus. 



