KEY, BASED UPON FLOWERS. 



f. Papilionaceous ; stamens 



Distinct 80. ROBINIA PSEUDACACIA. 



Monadelphous ; leaves glandular- dotted 154. DALEA SPim>SA. 



/ 2 . Subregular and imbricated in aestivation ; flowers 



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



i/ 2 . Dioecious; stamens 10; tree unarmed. .27. GYMNOCLADUS CANADENSIS. 

 g 3 . Polygamous ; stamens 5 ; tree armed with usually triple thorns 

 (Glfditschid) pods 



Linear, many-seeded 28. GLEDITSCHIA TRIACANTHOS. 



Obliquely ovate, 1-seeded 109. GLEDITSCHIA MONOSPERMA. 



f 3 . Regular, stamens 



ten ; petals distinct (Prosopis) 129. P. JULIFLORA. 



Indefinitely numerous ; petals united below (Acacia) 



155. A. MELANOXYLON. 



d 2 . Calyx superior adnate to the ovary ; stamens 

 c. 4 ; styles and stigmas 1 (Cornacece) flower cluster 



/. Enveloped with petal like involucral scales which envelope the head 

 while dormant and when developed are notched at apex 



88. C. FLORIDA. 

 Subtend the head and when developed are acute at apex 



185. C. NUTTALLII. 

 / 2 . Without petal-like involucral scales ; flowers in cymes 



87. C. ALTERNIFOLIA. 



e 2 . 5 ; styles 5 ; fruit a 5-seeded drupe- like berry 8. ARALIA SPINOSA. 



d 3 . Calyx adnate to the lower half of ovary only, but closely enveloping the 



hairy upper half in fruit 181. HETEROMELES ARBUTIFOLIA. 



ft 2 . Gamopetalous petals present and united ; stamens 

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

 (I. Irregular ; ovary 2-celled (Bignoniacece) ; leaves simple and 



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



Linear (Chilopsis) 134. C. SALIGNA. 



(V. Regular; stamens 5; leaves 



Pinnately compound (Sambucus) and glaucous 157. S. GLAUCA. 



Simple, glaucous 188. NICOTIANA GLAUCA. 



c 2 . Fewer than the lobes of the corolla 1 or 2; fruit drupaceous and 



Oily; corolla-lobes valvate 186. OLEA EUROPEA. 



Dry; corolla-lobes imbricated 112. OSMANTHUS AMERICANUS. 



e 3 . More numerous than the lobes of the corolla 

 d. Distinct and free from it (Ericaceae); fruit 

 Fleshy and ovary 



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



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



Dry, capsule septicidal (Rhododendron) 138. R. CALIFORNICUM. 



d*. Inserted on its base and filaments distinct 61. DIOSPYROS VIRGINIANA. 



b 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 and 

 e. 1-celled and 1-seeded; style stigmatic down the side (Nyssa): fertile ped- 

 uncles 2-5-flowered 9. N. MULTIFLORA. 



Single-flowered and short and downy 110. N. OGECHE. 



e 2 . Several-celled; calyx opening by a dehiscent lid (Eucalyptus); capsules 



axillary, top shaped 183. E. GLOBULUS. 



d? Ovary superior free from the caryx. 



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

 in heads, which are 



Solitary 13. PLATANUS OCCIDENTALIS. 



2-7 together in a moniliform spike 135. PLATANUS RACEMOSA. 



c 2 . Stipules not sheathing the stem or none. 



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

 (/. Double samara (Acer) 



7i. Leaves simple and palmately veined: flowers appearing 

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



