ORDEK 101. MARVELWORTS. 282 



COHORT III. 



THE AFETALOTJS EXOGENS. 



Essential Character. Flowering plants 

 vrith their stems growing by additions to the outside and the 

 wood in circular layers (ExoGENs), with the seeds inclosed in 

 seed-vessels (ANGIOSPEKMS), and the flowers destitute of petals 



ORDER C. ARISTOLOCHIACE^E. Birthworts 



Low herbs or climbing slirubs with alternate leaves, large flowers ; 

 calyx adhering to the ovary, valvate in bud, brown or dull colored ; 

 stamens 6-12, at top of the 6-celled, many-seeded otary. 



Analysis of the Genera. 

 Cal jx bell-form, regular, 3-cleft. Stamens 12. Herbs with creeping, 



underground sterna. Wild Ginger. ASA'RUM, 1 



Calyx tubular, bent, irregular. Anthars 6. Shrubby, erect or climbing, 



with very odd flowers. Birthwort. ARISTOLO'OHIA. 



ASARUM. Wild Ginger. 



1 A Canadense. Canafa W. Leaves in pairs, broad-reniform, with the single flower 



between the petioles scarcely above-ground. May-July, c. 



2 A. Tirginicum. Virginia W. Leaf solitary, round-ovate, cordate, the single flower 



much shorter than the petiole. Sepals obtuse. Mts. Va. S. April. 

 8 A. arifol'ium. Arum-lv. W. Leaf solitary, broadly hastate, with long, angular 

 lobes at base. Calyx throat contracted, lobes very short. Va. 8. April. 



ORDER CL NYCTAGINACE.E. Marvelworts. 



(ehrubs or t^ees) with swelling joints ; entire, opposite leaves ; 

 flowers surrounded by an involucre (which is, of course, calyx-like when 



the flower is solitary) : 



calyx often colored like a corolla, tubular or funnel-form, breaking off 

 above the 1 -eel led, 1 -seeded ovary. 

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