THE NATURAL SYSTEM. 157 



ANGIOSPERMS (aysjof, a vessel, 



seed), (Oak, Rose) 

 a. Flowers more generally perfect ; 

 &, Pistils complete, enclosing the ovules 



c, Seeds enclosed in a pericarp ; 



d, Embryo with only two cotyledons. 



QYMNOSPERMS (yujxvog, naked, 



(Pine, Yew)- 

 a, Flowers imperfect ; 

 6, Pistils scale-like, with no stigma; 



c, Seeds naked, not in a pericarp ; 



d, Embryo mostly with several whorled 



cotyledons. 



611. Two Classes also constitute the Eridogens, viz. : 



The PETALIFER^E (tfs'raXov, a petal, 

 (ps'pw, to bear) 



Plants of the endogenous structure, hav- 

 ing continuous stems and petaloid flowers ; 

 that Is, flowers invested with a whorled 

 perianth or none (Lily, Orchis, Rush). 



GLUMIFER.E (gluma, husk, fero, to bear) 

 Plants of the endogenous structure, hav- 

 ing jointed culms and glumaceous flowers ; 

 that is, invested with an imbricated per- 

 ianth of green glumes (Grasses, Grain*, 

 Sedges). 



512. Cohorts. The Classes are each of great extent, both as 

 to the number and the diversity of their families, and obviously 

 require a further subdivision. To effect this on strictly natural 

 principles, botanists have labored hitherto in vain. The truth 

 is, the members of these several classes are united by affinities 

 so equable as to render a further subdivision impossible except 

 by distinctions more or less arbitrary. So adjacent territories, 

 where rivers or other natural boundaries are wanting, must be 

 separated by artificial lines. 



513. The AXGIOSPERMS were subdivided by Endlicher into 

 three cohorts, and nearly all modern botanists have adopted his 

 plan under various names. 



1. Dialypefalce (&aXuw, to dissolve). Exogenous plants, having both calyx and co- 

 rolla, the latter composed of distinct petals (polypetalous\ sometimes slightly cohering 

 by the base of the stamens, rarely abortive. 



2. GamopetalcB (VOf&O^, union). Exogenous plants, having both calyx and corolla, 

 the latter composed of petals more or less united (monopetalous). 



3. Apetalce (a, privative). Exogenous plants with flowers having a calyx only, or 

 neither calyx nor corolla (acMamydeous). 



514. The class PETALIFER^E may be conveniently separated 

 into two cohorts as follows : 



1. Spadlci flora. Endogenous plants with flowers having no perianth, or a scaly one, 

 and borne 011 a thickened spadix, which is often enveloped in a spathe. 



2. Floridece. Endogenous plants with the flowers usually perfect and complete, the 

 perianth double, 3-parted, the outer often, and sometimes both, green. 



515. The class Glumifera is equivalent to the cohort Grami- 

 noidece, including the Sedges, Grains, and Grasses a truly 

 natural assemblage. 



516. The Sub-kingdom CRYPTOGAMIA is resolved into 

 groups which are analogous to those of the Phoenogamia. First, 



