38 FLORA. 



nearly 6 mm. hig , the top of the seed not covered by the fleshy integument. In 

 woods, Newf. to Man., N. J., in the Alleghenies to Va., and to la. April-May. 



Class II. ANGIOSPERMAE. 



Ovules (macrosporanges) enclosed in a cavity (the ovary) formed by 

 the infolding and uniting of the margins of a modified rudimentary leaf 

 (carpel), or of several such leaves joined together, in which the seeds are 

 ripened. The pollen-grains (microspores) on alighting upon the summit 

 of the carpel (stigma) germinate, sending out a pollen-tube which pene- 

 trates its tissues and reaching an ovule enters the orifice of the latter 

 (micropyle), and its tip coming in contact with a germ-cell in the embryo- 

 sac, fertilization is effected. In a few cases the pollen-tube enters the 

 ovule at the chalaza, not at the micropyle. 



There are two sub-classes, distinguished as follows : 



Cotyledon one ; stem endogenous. Sub-class i. MONOCOTYLEDONES. 



Cotyledons two ; stem (with rare exceptions) exogenous. 



Sub-class 2. DICOTYLEDONES. 



Sub-class i. MONOCOTYLEDONES. 



Embryo with a single cotyledon and the first leaves of the germinat- 

 ing plantlet alternate. Stem composed of a ground-mass of soft tissue 

 (parenchyma) in which bundles of wood-cells are irregularly imbedded ; 

 no distinction into wood, pith and bark. Leaves usually parallel-veined, 

 mostly alternate and entire, commonly sheathing the stem at the base 

 and often with no distinction of blade and petiole. Flowers mostly 3- 

 merous or 6-merous. 



Order I. PANDANALES. 



Our species aquatic or marsh plants, with narrow elongated leaves 

 and very small, imperfect and incomplete flowers in spikes or heads. 

 Perianth of bristles, or of chaffy scales. Ovary i, 1-2 -celled. Endo- 

 sperm mealy or fleshy. 



The order takes its name from the tropical genus Pandanus, the so- 

 called Screw-Pine. 



Flowers in terminal spikes. Fam. i. Typhaceae. 



Flowers capitate, the heads axillary to leaf-like bracts. Fam. 2. Sparganiaceae. 



Family i. TYPHACEAE J. St. Hil. 

 Cat-tail Family * 



Marsh or aquatic plants with creeping rootstocks, fibrous roots and 

 glabrous erect, terete stems. Leaves linear, flat, ensiform, striate, 

 sheathing at the base. Flowers monoecious, densely crowded in termi- 

 nal spikes, which are subtended by spathaceous, usually fugacious 

 bracts, and divided at intervals by smaller bracts, which are caducous, 

 the staminate spikes uppermost. Perianth of bristles. Stamens 2-7, 

 the filaments connate. Ovary i, stipitate, i-2-celled. Ovules anatro- 

 pous. Styles as many as the cells of the ovary. Mingled among the 

 stamens and pistils are bristly hairs, and among the pistillate flowers 

 many sterile flowers with clavate tips. Fruit nutlike. Endosperm 

 copious. The family comprises only the following genus : 



i. TYPHA L. 



Characters of the family. [Name ancient.] About 10 species, widely dis- 

 tributed in temperate and tropical regions. Besides those here described, another 

 occurs in Cal. 



* Contributed by the late Rev. THOMAS MORO:SG. 



