12 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
SYSTEMATIC TREATMENT OF THE VASCULAR PLANTS. 
SYNOPSIS OF THE LARGER GROUPS, WITH KEYS. 
Subkingdom PTERIDOPHYTA. 
Plants without flowers or seeds, producing spores, each of which, on germination, 
develops into a flat or 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 antheridia a fern or an allied plant is 
developed. 
KEY TO THE ORDERS. 
Leaves broad, entire or dissected; ferns or fernlike plants. 
Spores of 1 kind, borne in sporangia; plants not aquatic...1. FILICALES (p. 18). 
Spores of 2 kinds, borne in sporocarps; aquatics......2. SALVINIALES (p. 27). 
Leaves narrow, scalelike or awllike; mosslike or rushlike plants. 
Sporangia in a terminal cone; stems hollow..........3. EQUISETALES (p. 28). 
Sporangia in the axils of small or leaflike bracts; stems solid. 
4, LYCOPODIALES (p. 29). 
Subkingdom SPERMATOPHYTA. 
Plants with flowers which produce seeds. Microspores (pollen grains) borne in the 
microsporangia (anther sacs) develop each into a tubular prothallium; a macrospore 
(embryo sac) develops a minute prothallium and, together with the macrosporangium 
(ovule) in which it is contained, ripens into a seed. 
KEY TO THE CI.ASSES. 
Ovules and seeds borne on the face of a bract or scale; stigmas wanting. 
1. GYMNOSPERMAE (p. 30). 
Ovules and seeds borne in a closed cavity; stigmas present. 
2. ANGIOSPERMAE (p. 39). 
Class 1. GYMNOSPERMAE. 
KEY TO THE ORDERS. 
Staminate and pistillate flowers both in aments; perianth none; trees or shrubs with 
needle-like or scalelike leaves ........--.-..-.-+-------. 5. PINALES (p. 30). 
Staminate flowers in aments; pistillate flowers single or in pairs; perianth present; 
shrubs with jointed stems, the leaves reduced to sheathing scales. 
6. GNETALES (p. 38). 
Class 2. ANGIOSPERMAE. 
KEY TO THE SUBCLASSES. 
Cotyledon 1; stems endogenous; leaves parallel-veined. 
1, MONOCOTYLEDONES (p. 39). 
Cotyledons normally 2; stems exogenous; leaves not parallel-veined, or rarely appar- 
ently 80.2.2... 2.2.2 ee eee ee eee ee eee 2. DICOTYLEDONES (p. 154). 
