OF TENNESSEE. 59 



and endless multiplication of exceedingly minute agencies, 

 that often bring the wealth of nations on the verge of ruin, 

 like the phylloxera of the grape vine, the pebrine on the 

 silk worm, and scarlet fever and diptheria amongst our 

 children. And, one need not expect to success- 

 fully combat those enemies before the great mass of the 

 people is able to partake and to assist in a sqientific inves- 

 tigation. 



To determine the differences between the various grasses 

 requires careful study from even an advanced botanical 

 student. The graminese spread over the whole globe, are a 

 very numerous family, forming, in fact, one twenty-second 

 part of all phaenogamous plants, and containing about 300 

 genera and 4000 species. Of these, 74 genera with 287 

 species belong tp the flora of the United States east of the 

 Mississippi, and as they unmber amongst them all cereals, 

 they are unquestionably the most important part of the 

 vegetable kingdom for the interest of mankind. The fol- 

 lowing description of the family characters is given accord- 

 ing to Gray's Manual: 



Grasses, with usually hollow stems (culms) closed at the joints, alter- 

 nate two-ranked leaves, their sheaths split or open on the side opposite 

 the blade ; the hypogynous flowers imbricated with two-ranked glumes 

 or bracts ; the outer pair (glumes proper) subtending the Bpikelet of one 

 or se'seral flowers ; the inner pair (paleee or palets) enclosing each par- 

 ticular flower, which is usually furnished with two or three minute hy- 

 pogynous scales (squamulse.) Stamens one to six, commonly three ; 

 anthers versatile, two-celled, the cells distinct. Styles mostly two or two- 

 parted; stigmas hairy or feathery. Ovary one-celled, one-ovuled, form- 

 ing a seed-like grain (caryopsis) in fruit. Embryo small, on the outside 

 and at the base of the floury albumen. Koots fibrous, Sheath of the 

 leaves usually more or less extended above the base of the blade into a 

 scarious appendage (ligule.) Spikelets panicled or spiked. Inner (upper) 

 palet usually two-nerved or two-keeled, enclosed or partly covered by 

 the outer (lower) palet. Grain sometimes free, sometimes permanently 

 adherent to the palets. 



For an easier understanding of the structure of the grass- 

 flower and seed, and the technical terms used in describing 



