ROLL CALL 



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DIVISION III - TRACHEOPHYTA - Vascular Plants. 



Chakacteristics : Fibro- vascular system for transportati..,i „f raw mate- 

 rials up and food down; separation of specialized cl.l..njphyll-lK.ari..K 

 tissue ; adaptation to absorption of water from soil. 



Subdivision A — Primitive Vascular Plants — {Psilotum and Tmesipteris, Rhynia). 

 Characteristics : Fossil primitive vascular plants giving rise in tliree lines 

 to Lycopsida, Sphenopsida, and Pteropsida. 



Subdivision B — Lycopsida — Club mosses, ground pines (Lycopodium, Selagi- 

 nella). 



Characteristics: Stem clothed with small, numerous, spirally arranged 

 leaves; sporangia borne on upper surface of spowphyll; latter usually 

 grouped into terminal cones. 



Subdivision C — Sphenopsida — Horsetails (Equisetum). 



Characteristics : Hollow, typically jointed stems, bearing small leaves at 

 joints (nodes); stems ribbed; diaphragms often across stem at nodes; 

 sporangia borne in groups on stalked shield-shaped structures forming 

 terminal cones ; ribs opposite fibro-vascular bundles which are associated 

 with small air-filled canal; abundant in Paleozoic age; now only about 

 35 species. 



Subdivision D — Pteropsida — Ferns and seed-bearing plants. 



Characteristics: Typically large leaves; sporophytic generation domi- 

 nates ; sporangia relatively large. 



Class I — Filicineae — Ferns. 



Characteristics : Small, herbaceous plants with typical pinnately com- 

 pound leaves (fronds) ; stem relatively weak and inconspicuous ; roots 

 numerous but do not form an extensive system; small sporangia borne 

 on lower surface of leaf in groups usually protected by membrane (iiulu- 

 simu) ; spore germinates, forming small, thin gametophyte (prothallus), 

 which in turn bears antheridial and archegonial structures. About 15,000 

 species, some of which reach a height of 30 feet. From forms like the 

 ferns evolved the higher vascular plants whic-h dominate the earth's 

 surface today. 



Class II — Gymnosperil\e — Evergreens, pines, hemlocks, spruces, junipers. 

 Characteristics: Seeds freely exposed to air; usually nondeciduous 

 types; megaspore retained within megasporangium where it germinates 

 producing female gametophyte; integument, a new structure, enclo.ses a 

 sporangium and embryo sac; reduced male gametophyte transferred 

 directly to vicinity of female ; male obtains access to female gametophyte 

 by new structure (pollen tube); young sporophyte develops in contact 

 with and at expense of parental sporophyte; gametophyte with haploid 

 (x) number of chromosomes entirely parasitic upon sporophyte. Mem- 

 bers of this group are phylogenetically ancient; only about 450 living 

 species. 



Class III — Angiospermae — Deciduous trees and plants. Dicotyledons, oak, 

 maple, beech ; Monocotyledons, corn. 



