SPERMATOPHYTA 



SEED-BEARING OR FLOWERING PLANTS. 



Plants with flowers containing stamens, or pistils, or both, and 

 producing seeds containing an embryonic plant. Alternation of 

 generations not apparent, the gametophyte being exceedingly re- 

 duced. The pollen-grains (microspores) contained in the anther- 

 sacs of the stamens, after liberation and reaching the stigma of the 

 pistil or the naked ovules, germinate and produce a tube, by means 

 of which the egg-cell (macrospore) of the ovules (macrosporange) 



is fertilized. 



PAGE 

 Ovules and seeds borne on the surface of an open bract or scale; stigmas wanting. 



Class I. GYMNOSPERMAE 11 



Ovules and seeds in a closed cavity (ovary), formed by one or more united modified 

 leaves, with one or more stigmas at the end. 



Class II. ANGIOSPERMAE 20 

 Cotyledons usually single; earlier leaves alternate; leaves mostly parall el- veined ; 



stem endogenous. Subclass 1. MONOCOTYLEDONES 



Cotyledons mostly 2; earlier leaves opposite; leaves mostly netted-veined ; 



stem exogenous. Subclass 2. DICOTTLEDONES 185 



KEY TO THE FAMILIES. 

 Class 1. GYMNOSPERMAE. NAKED-SEEDED PLANTS. 



Perianth none; trees or shrubs with needle- or scale-like leaves not sheathing. 

 Pistillate flowers in aments; fruit a cone, either dry or berry-like. 



Carpellary scales subtended by bracts, never peltate; ovules inverted; buds 

 scaly ; wings of the seeds formed from a portion of the carpellary scales. 



1. PlNACEAE 11 



Carpellary scales not subtended by bracts, mostly peltate or fleshy; ovules 

 erect; buds naked; wings of the seeds, if present, a part of the seed- 

 coat. 2. JUNTPERACEAE 

 Pistillate flowers single or in pairs, without carpellary scales; fruit drupaceous 



or baccate. 3. TAXACEAE 



Perianth present, urn-shaped; pistillate flowers single or in pairs; horsetail-like 

 shrubs with jointed branches and the leaves reduced to sheathing scales. 



4. EPHEDRACEAE 



Class 2. ANGIOSPERMAE SEED-VESSELED PLANTS. 



Subclass 1. MONOCOTYLEDONES. 



Small lens-shaped, ellipsoid, or flask-shaped floating aquatics without leaves. 



15. LEMNACEAE 143 



Plants with true stems and leaves, the latter however, sometimes scale-like. 



Perianth rudimentary or degenerate, its members often bristles or mere scales, 



not corolla-like, or wanting. 



Flowers not in the axils of dry or chaffy bracts (glumes). 

 Perianth of bristles or chaffy scales. 



Flowers in elongate terminal spikes; fruit hidden among bristles. 



5. TYPHACEAE. 20 

 Flowers in globose lateral spikes; fruit not hidden among bristles. 



6. SPARGANIACEAE 20 

 Perianth fleshy or herbaceous, or wanting. 



Flowers in dense spikes subtended by an enlarged bract (spathe); 



fruit baccate; endosperm present; emersed water or bog plants. 



14. ARACEAE 143 



Flowers, if spicate, not subtended by a spathe; fruit drupaceous; 



endosperm wanting; submerged water plants. 



(1) 



