KEY, BASED UPON FLOWERS. 3 



e 3 . Ovary single and simple, with one parital placenta (Leguminosce) ; corolla 



/. Papilionaceous ; stamens distinct 80. ROBINIA PSEUDACACIA. 



/*, Subregular and imbricated in aestivation; flowers 



g. Perfect (Circidium) 128. C. TORKEYANUM. 



gr 2 . Direcious; stamens 10; tree unarmed. 



27. GYMNOCLADUS CANADENSIS. 



g*. Polygamous; stamens 5; tree armed with thorns usually triple 

 (Gleditschia) pods 



Linear, many-seeded .28. GLEDITSCHIA TRIACANTHOS. 



Obliquely ovate, 1-seeded 109. GLEDITSCHIA MONOSPERMA. 



/ 3 . Regular (Prosopis) 129. P. JULIFLORA. 



<$ 2 . Calyx superior adnate to the ovary; flowers in umbels; stamens 5; 

 styles 5; fruit drupe-like with 5 cells each with a single ovule (Aralia)', 



arborescent and armed with prickles . . 8. ARALIA SPINOSA. 



l . Gamopetalous petals present and united; stamens 

 C. As many as the lobes of the corolla which is 

 d. Irregular; ovary 2-celled (Bignoniacem); leaves simple and 



Broadly-ovate (Gatalpa) 89. C. BIGNONIOIDES. 



Linear (Chlopsis) 134. C. SALIGNA. 



d*. Regular; stamens 2 112. OSMANTHUS AMERICANUS. 



c 2 . Fewer than the lobes of the corolla; inserted 



d. On its base and filaments distinct 61. DIOSPYROS VIRGINIANA. 



d 2 . On an hypogynous disk; ovary 



5-celled, several ovules in each cell 132. ARBUTUS MENZIESII. 



5-10-celled, single ovule in each cell. . . 133. ARCTOSLAPHYLOS PUNGENS. 

 3 . Apetalous without petals. 

 c. Flowers not in catkins; pistil one, simple or compound, and the cells of the 



ovary containing 1-2 seeds each. 



d. Ovary inferior adnate its whole length to the calyx-tube 1-celled and 

 1-seeded; style 1, stigmatic down the side (Nyssd); fertile peduncles 



2-5-flowered 9. NYSSA MULTIFLORA. 



Single flowered and peduncle short and downy .110. NYSSA OGECHE. 



Two or more flowers 9. N. MULTIPLORA. 



d*. Ovary superior free from the calyx. 



e. Stipules sheathing the stem ; trees with naked monoecious flowers ar- 

 ranged in heads, which are 



Solitary 13. PLATANUS OCCIDENTALS. 



2-7 together in a monilif orm spike 135. PLATANUS RACEMOSA. 



e 2 . Stipules not sheathing the stem or none. 

 /. Ovules a pair in each cell of the ovary, which becomes in 

 g. Fruit a double samara (Acer). 

 h. Leaves simple and palrnately veined; flowers appearing 



i. With the leaves in pendulous corymbs 7. A. SACCHARINUM. 



i 3 . Before the leaves in short umbels, and 



Apetalous; young fruit woolly 26. A. DASYCARPUM. 



Petals present, linear-oblong; fruit smooth. .53. A. RUBRUM. 

 i 1 . After the leaves, in drooping racemes 



79. A. PENNSYLVANICUM. 



h*. Leaves compound 54. A. NEGUNDO. 



gr 9 . Fruit a 1-celled and 1-seeded samara (Fraxinus). 



