Order 101.— MARVEL WORTS. ^S9 



COHORT III 



THE APETALOUS EXOGENS. 



Essential Character. — Flowering plants (PniExoGAMiA), 

 with their stems growing bj additions to the outside and the 

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

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

 (Apetalje). 



Order C— ARISTOLOCHIACE.E. Birthworts 



Low herbs or climbing shruhs with alternate leaves^ large Jfowers ; 

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

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



Analysis of the Genera. 

 Ca]yx bell-form, regular, 3-cIeft. Stamens 12. Herbs with creeping, 



underground stemSi Wild Ginger. Asa'rum, 1 



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



with very odd flowers. Birthicort. Aristolo'chia. 



AS ARUM. Wild Ginger. 



1 A Oanadense. Canada W. Leaves in pairs, broad-renifbrm, with the single flower 



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



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



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



3 A. ariforium. Arum-lv. W. Leaf solitary, broadly hastate, with long, angular 



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



Order CI.— NYCTAGINACE.E. Marvelworts. 



Herls (shrubs or trees) 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, brejiking off 



al)0ve the 1 -colled, L seeded ovary. 



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