THE NATURAL SYSTEM. 171 



or impossible to fix upon characters so definite a<i to circumscribe completely any 

 one group, while at the same time they exclude every member of the surrounding 

 allied groups. 



897. Second division. The Flowering plants are next resolved into 

 two great provinces, indubitably marked by nature's own hand, and em- 

 ployed in every natural method. The following is their diagnosis. 

 Exogenj: (e£w, without, -yewuo, to generate), or Dicotyledonous Plants. 

 <!•, Growing by layers external to tho wood, internal to the bark, 



b, Leaves net-veined, 



c, Flowers 4 or 5-parted, rarely 3-parted, 



d, Seeds with two or more cotyledons, and 



e, The radicle producing an axial root. 



ENDOGEN.E, (evSov, within, yevvuu), or MONOCOTYLEDONOUS PLANTS. 



a, Growing by scattered internal wood-bundles, 



b, Leaves parallel-veined, 



c, Flowers very generally 3-parted, 



d, Seeds with one cotyledon, and 



e, The radicle never producing an axial root. 



80S. Third division ; — classes. The provinces are next broken 

 into classes — groups of the third rank in extent. Two are constituted 

 of the Exogens, viz. : 



Angiosperm.£ (ayyeioc, a vessel, orrepina, seed) (oak, rose). 



a, Flowers more generally perfect or complete, 



b, Pistils complete, inclosing the ovules, 



c, Seeds inclosed in a pericarp. 



d, Embryo with only two cotyledons. 

 Gyjinosperm-E (yvfivuc, naked, c-epfia) (pine, yew). 



a, Flowers imperfect and incomplete, 



b, Pistils scale-like, without a stigma, 



c, Seeds truly naked, that is, destitute of a pericarp, 



d, Embryo mostly with several whorled cotyledons. 

 Two classes are formed from the Endogens, viz. : 



Petalifer.£ (TvtTa'kov, petal, (bepu, to bear). 



Plants of the endogenous structure, with flowers constructed on the usual 

 plan ; perianth of one or more whorls of petaloid organs, or wanting (lily, 

 Orchis, rush) 

 Gujmifer^e (gluma, husk, fero, to bear). 



Plants of tho endogenous structure, the flowers invested with an im- 

 bricated perianth of glumes, instead of petals and sepals (grasses, grains, 

 sedges). 

 899. Divisions of the cryptogamia. This sub-kingdom is na- 

 turally divided into two provinces, the Acrogens, and Thallogens, — 

 terms founded upon their mode of vegetation. The former include 

 those tribes which make some approximation towards the Phsenogamia, 

 the latter include the lowest tribes in the vegetable kingdom. 

 ACR0GEN.E (uKpov, the summit, yevvuu). 



Flowerless plants having a regular stem or axis, which grows by the ex- 

 tension of tho apex only, without increasing at all in diameter, generally 



