SYNOrTICAL KEY TO THE ORDERS. ^„ 



Series II. CRYPTOGAMOUS or FLOWERLESS PLANTS. Flowers witliout 

 stanieiis or pistils, in fruit producing spores instead of seeds. 



Class III. ACROGENOUS PLANTS. Growing from the apex of a distinct axis, 

 mostly with distinct leaves. 



Subclass I. VASCULAR ACROGENS. Pkints with both woody and cellular tissue: 

 reproductive organs of one or both sexes produced upon a prothallus developed from 

 the spore. 



Division I. ISOSPOROUS VASCULAR ENDOGENS. Spores only of one kind, the pro- 

 thallus bearing organs of both sexes. 



120. Equisetaceae, p. 329. Cylindric jointed hoUow-stenimed plants, with toothed sheaths. 



Fructification in a terminal spike. 

 12L Ophioglossaceae, p. 331. Fronds often ferndike, erect in vernation. Sporangia gloliosp, 



coriaceous, in special spikes or panicles. 



122. Filices, p. 332. Ferns, with fionds circinate in vernation, bearing tlic fractification on the 



under surface or beneath the margin. 



Division II. HETEROSPOROUS VASCULAR ACROGENS. Spores of two kinds, one pro- 

 ducing a iirothallus with archegonia, the other smaller and containing antherizoids. 



123. Selaginelleae, p. 349. The two kinds of spores borne separately upon the upper side of the 



base of linear grass-like radical leaves or in the axils of small leaves arranged in 4 ranks 

 upon a stem. 



124. Marsiliaceae, p. 351. Spores of both kinds togetlier in peduncled capsules borne upon a 



rhizome. Leaves filiform or pedately quadrifoliolate. In nmd. 



125. Salviniaceae, p. 352. Small floating plants, the sjjores borne in separate capsules at tlie 



base of the frond. 



Subclass II. CELLULAR ACROGENS. Phints with cellukr tissue only : reproduc- 

 tive organs borne upon the stem or branches. 

 A. Capsules mostly opening by a lid, containing numerous spores without spiral fibres {cln/rrs). 



126. Musci, p. 353. Branches not regularly fascicled along the stem. Tissue of the leaves 



homogeneous. Spores of one kind. 



127. Sphagnaceae, p. 421. Branches regularly fascicled. Tissue formed of colorless cells and 



intermediate gi-een linear ducts. Spores of two kinds. Pale flaccid bog plants. 



B. Capsule not opening by a lid : spores mixed with elaters. 



128. Hepaticae. Stems procumbent, leafy with alternate or distichous leaves, or thalloid. 

 C. Sporangium consisting of a single large spore surrounded by spirally arranged tubes. 



129. Characeae. Submerged aquatics, with whorled branches, consisting of tubular cells 



placed end to end. 



Class IV. THALLOGENS. Growth chiefly peripherical and horizontal, without 

 definite axis, mostly without leaves, and composed wholly of cellular tissue : spores 

 not developing a prothallus. [Added here to complete the Series.] 



130. Lichenes. Not parasitic, on exposed surfaces, prostrate and crustaceous or frondosc, or 



erect, containing chlorophyllose granules. Eeproductive organs of two kinds, apothccia 

 and S2Krmogonia. 



131. Fungi. Parasitic, wholly without chlorophyll, the organs of vegetation {mycelium) mostly 



subterranean or concealed, the reproductive very various in form and structure. 



132. Algae. Aquatic, mostly submerged, not parasitic, always containing chlorophyll ami 



usuaUy highly colored. Reproductive organs very various. 



