48 A TEXTBOOK OF THEORETICAL BOTANY 



(b) Lycopsida. Sporophyte with numerous, usually small leaves 

 (microphyllous). Homosporous or heterosporous. Sporangia 

 free, borne on or axillary to sporophylls. Gametophyte reduced, 

 saprophytic or enclosed in the spores. 



(f) Sphenopsida. Sporophyte with jointed stems and small leaves in 

 whorls (microphyllous). Homosporous. Sporangia clustered, in 

 terminal strobili. Gametophyte green. 



{(J) Ptkropsida. Sporophyte with large leaves (megaphyllous). Homo- 

 sporous or heterosporous. Sporangia clustered on foliar organs. 

 Gametophyte either green, or reduced and enclosed in the spores. 



5. Spermatophyta. Sporophyte with stems, roots and leaves. Vascular 

 tissue present. Heterosporous. Microspores (pollen grains) and mega- 

 sporse (embryo sacs) produced in distinctive sporangia. Megasporangia 

 with integuments, developing into seeds. Gametophytes extremely reduced, 

 enclosed in the spores. 



{a) Pteridospermae. Leaves fern-like. Sporangia borne on normal 

 or only slightly reduced leaves, not aggregated into flowers. 



(b) Gymnospermae. Sporangia aggregated into strobili (cones), each 



usually containing only one type of spore. Megasporangia exposed. 



(c) Angiospermae. Sporangia either in separate or in the same flowers, 



Alegasporangia enclosed in carpels, which ripen into fruits. 



(i) Dicotyledons. Embryo with two cotyledons. Leaves mostly 



net-veined. 

 (2) Monocotyledons. Embryo with one cotyledon. Leaves 



mostly parallel-veined. 



OUTLINE CLASSIFICATION OF TYPES DESCRIBED 



THALLOPHYTA 



A. Algae. 



(i) Euglenophyceae. 



Euglenales. Englena. 

 (ii) Chlorophyceae. 



Volvocales. Chlamydomonas, Haeniatococcus, Goniiim, 



Pandorina, Eudorina, Volvox. 



Chaetophorales. Pleurococciis, Coleochaete. 



Ulotrichales. Ulothrix. 



Oedogoniales. Oedogonium. 



Conjugales. Spirogyra. 



Siphonales. Bryopsis, Vaiicheria. 



Siphonocladiales. Cladophora. 



(iii) Cyanophyceae. 



Hormogoneales. Nostoc. 



