A KEY, BASED MAINLY UPON THE FLOWERS, 



Designed as an Aid in the Identification of the Species represented in 



Parts I, II and in. 



a. Angiospermae seeds in a closed ovary. 

 b. Polypetalous petals present and distinct. 

 c. Stamens numerous, more than 10, and 



cl. Calyx inferior wholly free from the pistil or pistils. 



e. Pistils numerous and cohering in a cone-like mass. (Magnoliacice.) 

 /. Anthers opening inward ; leaves folded lengthwise in the bud (Magnolia), 

 pointed at both ends and 



Thick, glaucous beneath 51. M. GLAUCA. 



Thin, green beneath 1. M. ACUMINATA. 



/-'. Anthers opening outward and leaves folded crosswise in the bud. 



2. LlRIODENDRON TULIPIFERA. 



e 2 . Pistil solitary and 



/. One-celled, style single, flowers perfect, stone of drupe horny (Prunus), 

 turgid ovate, marginless; flowers in 



Racemes terminal 29. P. SEROTINA. 



Corymbose umbels 55. P. PENNSYLVANICUM. 



Umbels 56. P. AVIUM. 



/"-. Compound as shown by the styles and cells of ovary; calyx valvate in 

 the bud, deciduous (Tiliacece); stamens somewhat polydelphous (Tilia) 

 and with 5 petal-like scales opposite the petals . . .3. T. AMERICANA. 

 d?. Calyx superior adnate to the ovary which is 

 e. 2-5-celled and fruit a 

 /. Pome with 2-5 papery cartilaginous carpels (Pyrus) 



Styles united below 30. P. MALDS. 



Styles distinct 57. P. COMMUNIS. 



/-. Pome drupe-like with 1-5 bony seeds 58. CRAT^EGUS PUNCTATA. 



c-. Ovary 10- celled 59. AMELANCHIER CANADENSIS. 



c 2 . Stamens few, not more than 10, alternate with the petals when of the same 



number. 

 il. Calyx inferior free from the ovary. 



t\ Ovaries 2-5, separate; stamens distinct and inserted on the receptacle; 

 trees with pinnately compound and uniformly opaque leaves. 



4. AlLANTHUS GLANDULOSUS. 



e*. Ovary single, but compound as shown by the cells, styles or stigmas. 

 f. One-celled and one-seeded; styles or stigmas three; shrubs or trees 

 with regular flowers (Anacardiaceat); leaves compound with 11-31 

 oblong lanceolate acuminate leaflets; common petiole densely villous 



and not winged; flowers in terminal thyrses 5. RHUS TYPHINA. 



/ 2 . Two-several celled and flowers 



Irregular (Aesculus) 6. AE. HIPPOCASTANUM. 



Regular, stamens as many as the petals; trees with pinnately- veined 



leaves; calyx minute; fruit berry-like 52. ILEX OPACA. 



e 3 . Ovary single and simple with one parietal placenta; corolla subregular 



(not papilionaceous) and imbricated in aestivation. 

 /'. Flowers dioscious; stamens 10; tree unarmed. 



27. GYMNOCLADUS CANADENSIS. 



/ 2 . Flowers polygamous; stamens 5; tree armed with thorns (Gleditschia) 

 which are triple and pods linear 28. G. TRIACANTHOS. 



