NATURAL SYSTEM. 189 



plants whose flowers have both calyx and corolla, with 

 petals more or less united ; as, Elder, Arrow-wood, etc. 



478. COHORT 3, C. Apetalae. Dicotyledonous plants, 

 whose flowers have a calyx but no corolla, and some- 

 times neither ; as, Ragweed, Goosefoot, etc. 



479. CLASS II. Gymnosperms, Dicotyledones or Poly- 

 cotyledones. Plants whose seed is not inclosed by a 

 vessel or pericarp, derived tfrom the Greek words 

 ytyzvo^, naked, and anepfm, seed, naked seed. Stem 

 elongated, solid ; leaves nearly parallel-veined ; flowers 

 not perfect ; pistil scale-like ; no stigma ; ovules not 

 inclosed in a vessel ; embryo with two or more oppo- 

 site or whorled cotyledons. 



480. COHORT 4, D. Coniferae. Pines, Spruces, and 

 other cone-bearing trees and shrubs.- 



481. CLASS III. Monocotyledones. Plants whose em- 

 bryo has one cotyledon, or one seed leaf. Greek [i6vo$, 

 alone or one, and Korv^dov. Blade of the leaf usually 

 divided into two parts by a prominent midrib, with veins 

 extending from the base to the apex parallel to the 

 midrib ; flowers usually three-parted ; root not axial. 



This class is separated into three cohorts. 



482. COHORT 5, E. Spadiciflorae. Monocotyledonous 

 plants, with flowers on a spadix, frequently enveloped 

 by a spathe ; Palms, Calla, and pond weeds. 



483. COHORT 6, F. Petaloideae. Monocotyledonous 

 plants whose flowers are usually perfect and complete ; 

 floral envelope three-parted and double ; outer whorl 

 colored green ; as, Lily, Lily of the Valley, etc. 



484. COHORT 7, G. Glumiferae. Monocotyledonous 

 plants whose floral envelope is chaff-like ; ovary single, 

 with one ovule ; as, grass-like plants, Wheat, Rye, the 

 Sedges, etc. 



