KEY TO THE ORDERS. 
Subkingdom PTERIDOPHYTA. 
Plants without flowers or seeds, but producing spores each of which, on 
germination, develops into a flat or an irregular prothallium. The prothallia 
bear the reproductive organs (antheridia and archegonia). As a result of 
the fertilization of an egg in the archegonium by a sperm produced in the 
antheridium a fern or an allied plant is developed. 
Page. 
Leaves broad entire or dissected. (Fern-like plants.) 
Spores of one kind, minute, borne in sporangia. 
Vernation straight or inclined; eusporangiate, the sporangia ringless, 
leathery, opening by a transverse slit, arranged in spikes or panicles. 
Order i. Ophioglossales. i 
Vernation circinate; leptosporangiate, the sporangia membranous, pro¬ 
vided with a ring which opens elastically. Order 2. Filicales. i 
Spores of two kinds, minute microspores and larger macrospores, borne 
in sporocarps ; leaves filiform or quadrifoliate. Order 3. Salviniales. 5 
Leaves scale-like or awl-like. (Moss-like or rush-like plants.) 
Sporangia in an apical cone, borne under peltate scales: stems hollow, 
rush-like. Order 4. Equisetales. 5 
Sporangia in the axils of small or leaf-like bracts : stems solid. 
Leaves awl-like, often much elongated, borne on a short corm-like cau- 
dex: aquatic plants. Order 5. Isoetales. 5 
Leaves narrow or scale-like, flat, borne on erect or creeping stems : ter¬ 
restrial plants. Order 6. Lycopodiales. 6 
Subkingdom SPERMATOPHYTA. 
Plants with flowers which produce seeds. Microspores (pollen-grains) 
borne in microsporangia (anther-sacs) develop each into a tubular prothal¬ 
lium; a macrospore (embryo-sac) develops a minute prothallium, and to¬ 
gether with the macrosporangium (ovule) in which it is contained, ripens 
into a seed. 
Ovules and seeds borne on the face of a bract or a scale: stigmas wanting. 
Class 1. Gymnospermae. 7 
Ovules and seeds in a closed cavity (ovary) : stigmas present. 
Class 2. Angiospermae. ii 
1. Gymnospermae. 
Staminate and pistillate flowers both in aments; perianth none; trees or 
^ shrubs with needle- or scale-like leaves. Order 7. Pinales. 7 
Staminate flowers in aments; pistillate ones single or in pairs; perianth 
present, urnshaped; ours horsetail-like shrubs with jointed branches and 
leaves reduced to sheathing scales. Order 8. Gnetales. 10 
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