60. Convolvulus arvensis, (L.,) Bind-weed, (p.) This foreign plant has been introduced into some portions of our country, and will give the farmers much trouble if they do not carefully guard against it.

61. Cuscuta epilinum, (Weihe.) Dodder, flax-vine, (a.) This remarkable parasitic plant, somewhat resembling copper-wire in appearance, was introduced with our flax crop, and was formerly a great pest in that crop, by winding round and entangling branches of stalks so as to spoil them; but the vine has become rare, and has nearly died out since the culture of flax has declined among us.

62. Solanum nigrum, (L.,) Night-shade, (a.) Frequent in shaded, waste places about dwellings. It is reputed to be deleterious in its properties, and ought, therefore, to be carefully excluded from the vicinity of all farm-houses, where its berries may tempt children to "pluck and eat."

63. Solanum carolinense, (L.,) Horse Nettle, (p.) An exceedingly pernicious weed, and the roots are so penetrating and so tenacious of life that it is difficult to get rid of. It was probably introduced from the South by Humphrey Marshall into his botanic garden at Marshallton, Pennsylvania, whence it has gradually extended itself round the neighborhood, and forcibly illustrates the necessity of caution in admitting mere botanical curiosities into good agricultural

districts.

64. Datura stramonium, (L.,) Thorn Apple, Jamestown (or Jimson) weed, (a.) Two varieties of this coarse, fetid, narcotic plant (which is probably of Asiatic origin) are common among us as an obnoxious weed, and they should be carefully excluded from the vicinity of all farm-houses.

65. Enslenia albida, (Nutt,) Whitish Enslenia, (p.) This twining plant, allied to the Asclepias or Milk-weed family, and happily as yet unknown to the farmers of the eastern States, is reported by Prof. Short, a distinguished betanist of Kentucky, to be an intolerable nuisance on the farms along the river banks in Ohio, Illinois, &c.

DIVISION III-APETALOUS EXOGENS; Corolla usually wanting.

66. Phytolacca decandra, (L.,) Poke-weed, pigeonberry, (p.) This stout native is everywhere frequent in rich soil. The turions, or tender radical shoots, in the spring of the year afford a popular substitute for those of asparagus: nevertheless, the plant is regarded and treated as a weed by all neat farmers. 67. Chenopodium album, (L.,) Lamb's Quarter, goose-foot, (a.) This coarse and rather homely weed has become common and quite troublesome in gardens. 68. Amaranthus hybridus, (L.,) Pig-weed, (a.) A repulsive looking weed. an anuoyance in gardens and cultivated lots in the latter part of summer. If permitted to mature its seed it soon becomes very abundant.

69. Amaranthus albus, (L.,) White Amaranth, (a.) Another coarse weed in the farm yards of the middle States. Although supposed by some to be a native of Pennsylvania, it has a foreign habit and appearance, and probably came from tropical America.

70. Amaranthus spinosus, (L.,) Thorny Amaranth, (a.) This odious bushy weed, supposed to be a native of tropical America, is common in unfrequented streets and outskirts of our seaport towns, and is a vile nuisance wherever appears. It cannot be too sedulously guarded against. Hoeing on its first ap pearance is often effectual for its destruction.

71. Polygonum pennsylvanicum, (L.,) Knot-weed, (a.) A common worthles weed on road sides and in waste places about neglected farm-houses.

72. Polygonum pucicaria, (L.) Lady's Thumb, spotted knot-weed, (a.) Re sembles the preceding, and rather smaller, but equally worthless wherever in

troduced.

73. Polygonum hydropiper, (L.,) Water Pepper, smart-weed, (a.) A natu

Mowers

ralized weed as worthless as most of the species are, though this is even more obnoxious than the preceding, being a highly acrid plant, and sometimes causing obstinate ulcerative inflammation when incautiously applied to the skin. 74. Polygonum sagittatum, (L.,) Arrow-leaved Tear-thumb, (a.) and haymakers are apt to be familiar with this annoying native weed in the second crop of swampy meadows. Another kindred species, viz. Parifolium, (L.,) or Halbert-leaved Tear-thumb, is an accompanying and equally obnoxious weed. Ditching and draining are the remedies for the evil. Several other Polygonums occur, equally worthless, but rather less offensive.

75. Rumex crispus, (L.) Sour Dock, curled dock, (p.) An unsightly and objectionable foreign weed, too extensively known.

76. Rumex obtusifolius, Bitter Dock, broad-leaved dock, (p.) This foreign species is now more objectionable than the preceding, but is not quite so prevalent. There is also a little foreign species, well known for its acidity-the R. acetosella, (L.,) Field or Sheep Sorrel, (p.,) often so abundant as to be a nuisance on the farm. Improving the land, especially by adequate dressing of lime, is believed to be the best mode of expelling this and many other obnoxious

weeds.

77. Euphorbia hypericifolia, Eye-bright, spurge, (a.) This is a common weed in dry pasture fields, especially in thinnish sandy soils, and has been suspected (how justly has not been determined) as the cause of the disagreeable salivation or slabbering with which horses are sometimes affected in the latter part of summer. There is another flatty, prostrate, bunching little species, E. maculate, (L.,) often abundant in Indian cornfields and other cultivated grounds.

78. Urtica dioica, (L.,) Nettle, stinging nettle, (p.) An exotic rather frequent in waste places about farm houses, well known to those who have come in contact with them.

CLASS II.-ENDOGENOUS PLANTS; Inside Growers.

79. Symplocarpus fœtidus, (Salish,) Swamp Cabbage, skunk weed, (p.) A worthless native weed in wet and swampy meadows, readily known by its skunklike odor when wounded.

80. Sagittaria variabilis, (Englin,) Arrow-head, (p.) A common native plant of no value, found in sluggish ditches and swampy meadows. The roots, or base of stem, often produce large oval tubers in autumn, which tempt hogs to root for them, and thus disfigure the grounds in which they occur.

81. Anacharsis canadensis, (Planchon, Udora, Nutt,) Water-reed, (p.) This slender aquatic is supposed to be indigenous in our sluggish streams, where it often abounds, and may possibly become troublesome in our canals. It has been introduced into England, where its presence impedes the navigation of the canals to a serious extent.

82. Smilax rotundifolia, (L.,) Green Brier, rough bindweed, (p.) This is common in thickets, and a variety of it, S. Caduca, (L.,) often abounds in poor, neglected old fields.

83. Ornithogalum umbellatum, (L.,) Ten O'clock, (b.) This exotic from the gardens in many places multiplies its bulbs so rapidly as to alarm the farmer,▾ if neglected. The bulbs are exceedingly tenacious of life, and when once in possession of the soil, it is an almost hopeless task to get rid of them.

84. Allium vineale, (L.,) Field Garlic, crow garlic, (p.) Tradition says this species was introduced by the first Welsh immigrants to Pennsylvania for the purpose of affording an early pasture, particularly for sheep. It was formerly so abundant in some districts as to be quite an annoyance, by imparting a disgusting flavor to milk and butter, and injuring the manufacture of wheat flour. By good farming and a judicious rotation of crops the evil has been much

abated.

85. Juncus effusus, (L.,) Common or Soft Rush, (p.) There are numerous species of this worthless native weed, but this is the best known, and perhaps the most objectionable, as it has a constant tendency to form unsightly bunches, or tussocks, in moist low grounds. Mr. Elliott, an eminent botanist, says that in South Carolina this Rush occupies and almost covers rice fields as soon as they are thrown out of cultivation.

86. Cyperus phymatodes, (Muhl., Nut.,) Grass of Florida, (p.) This species is fortunately somewhat rare, as yet, in the northern and middle States, but it is a great pest to the agriculture of the South.

87. Cyperus hydra, (Mx.,) Coco grass, nut grass of South Carolina, (p) This is regarded by the southern planters as the most intolerable pest of their agriculture. Mr. Elliot says: 'It shoots from the base of its stem a threadlike fibre, which descends perpendicularly eight to eighteen inches, and then produces a small tuber. From this horizontal fibres extend in every direction, producing new tubers at intervals of six or eight inches; and these immediately shoot up stems to the surface of the earth, and throw out lateral fibres to form a new progeny. This process is interminable, and it is curious to see what a chain or net-work of plants and tubers can, with some care, be dug up in a loose soil. The only process yet discovered by which this grass can be extirpated is to plough or hoe the spots in which it grows every day through the whole season. In their perpetual efforts to throw their leaves to the light the roots become exhausted and perish; or, if a few appear the next spring, they can easily be dug up."

88. Carex tentaculata, (Muhl.,) Many-beaked Sedge, (p.) A very common species, in swampy low ground, of the large and unprofitable genus of sedges. 89. Carex stricta, (Lam.,) Tussock Sedge, (p.) This is one of the most common, and most difficult to manage, of all our sedges. Its roots are apt to form large dense tufts or "tussocks" in swamps. The careful farmers sometimes get rid of those tussocks by digging them out, and, when dry, collecting them in large heaps, burning them, and using the ashes as a manure. Of this remarkable and very numerous genus, (Carex,) Dr. F. Boott, an accomplished botanist of London, has now in hand one of the noblest and most elaborately illustrated monographs ever issued from the press.

90. Panicum sanguinale, (L.,) Crab grass, finger grass, (a.) In the middle States this troublesome grass abounds in gardens in the latter part of summer, and is frequent also in Indian corn fields, but may be kept in tolerable subjec tion by the early and faithful use of the instrument known as the "cultivator." The crab-grass is regarded as a serious pest in the plantations along the lower Mississippi.

91. Panicum capillare, (L.,) Hair-like Panicum, "Old Witch" grass, (a) This worthless species flourishes best in a light sandy soil, but is usually more or less abundant in corn-fields. In autumn the dry culms break off and the light-spreading panicles are rolled over the field by the winds, until they accumulate in great quantities along fence and hedge rows.

92. Panicum crus-galli, (L.,) Cock-foot Panicum, barn-yard grass, (a) This coarse homely grass is said to be an inhabitant of all quarters of the globe. It is usually found in the latter part of summer, rather abundant along drains of barn-yards and other waste places.

93. Sitaria glauca, (Beauv.,) Bristly Fox-tail grass, (a.) All our weed-like species of this genus are believed to be naturalized strangers here. This one usually makes its appearance in abundance among the stubble, after a wheat crop, and is frequent in pastures, orchards, &c., when not kept down by a more valuable growth. The S. viridis, (Beauv.,) called green fox-tail or bottle grass, is about equally worthless, but not quite so prevalent.

94. Sitaria virticellata, (Beauv.,) (a.) The adhesive bristles of this species,

frequenting gardens and neglected lots, are calculated to make it something of a nuisance if permitted to become abundant.

95. Cenchrus tribuloides, (L.,) Bur grass, hedge-hog grass, (a.) This pestilent nuisance is quite abundant in the sandy districts of New Jersey and along the great northern lakes.

this

96. Cynodon dactylon, (Pers.,) Dog's-tooth grass, Bermuda grass, (p.) Of grass, which has found its way from Europe into Virginia and other southern States, Mr. Elliot remarks: "The cultivation of it on the poor and extensive sand-hills of our middle country," (viz., in South Carolina,) "would probably convert them into sheep-walks of great value; but it grows in every soil, and no grass, in close rich land, is more formidable to the cultivator. It must, therefore, be introduced with caution."

97. Bromus secalinus, (L.,) Cheat, chess, broom grass, (a.) This is a wellknown intruder among our crops of wheat and rye, and often appears in the same fields for a year or two after those crops, but it is soon choked out by the perennial grasses.

This plant is an annual, and easy to overcome by care in sowing clean wheat, by keeping fence corners and field borders clear, and in establishing a proper rotation in cropping. The vulgar error, that this grass is merely transmuted wheat, came to us with the earliest immigrants, and, notwithstanding the boasted "march of mind," it yet prevails among a certain class of farmers to a consid

erable extent.

98. Triticum repens, (L.,) Couch grass, Quitch grass, (p.) This species of triticum, which is quite distinct in habit from the cultivated wheat, has found its way into some districts of our country, and is a pernicious intruder, when fully introduced, by reason of the exceeding tenacity of life in its rhizomas, or creeping subterranean stems.

99. Andropogon nutans, (L.,) Wood grass, Indian grass, (p.) This and two or three other species of native Indian grasses are common in our sterile grounds, and are no better than mere weeds.

SERIES II.-CRYPTOGAMUS, or Flowerless Plants.

100. Pteris aquilina, (L.,) Brake, bracken of the Scotch, (p.) This large fern is often abundant in moist woodlands and borders of thickets, and in our wild forests it affords a favorite shelter, or hiding-place, for deer and other game, but it is little better than a weed on the farm.

Having thus disposed of the most prominent weeds in our agriculture, it remains merely to mention, very briefly, three or four of the injurious cryptogams, among the lower order of the fungi, viz:

Merulius lachrymans, (Schum.,) Dry-rot. This fungus, with some others which infest timber in places where a damp air is confined, as in houses and ships, is very injurious. It is said to be remedied by a wash of diluted sulphuric acid.

Ascophora mucedo, (Link.,) Mould, bread-mould. This minute fungus usually abounds on moist decaying substances, and is well known to housewives as growing plentifully on bread and pastry which have begun to "spoil;" yet it is probable that many of them have never suspected it of being as genuine a plant as any weed that grows on the farm.

Uredo segetum, (Pers.,) Blight, smut, brand. This is usually found within the glumes and fruit of wheat, barley, and other grasses, speedily filling the whole with a profuse black dust.

Puccinia graminis, (Pers.,) Mildew, rust. This often operates injuriously on wheat crops in warm, close, foggy weather, near harvest time; especially where the crop is a little backward and mingled with grass or herbage.

OBSERVATIONS ON ATMOSPHERIC HUMIDITY.

BY J. S. LIPPINCOTT, HAddonfield, N. J.

To a large and intelligent class of readers of the Agricultural Department reports, grape-growing has become an object of absorbing interest. Those of this class who may have read a paper on "The Climatology of American Grape Vines," in the report for 1862, and its continuation under the title of "Geography of Plants," in that for 1863, will have observed that success was promised in certain zones of summer temperature, provided the atmospheric humidity were not there deficient, either permanently or for the season. This element, so variable, seems scarcely less important than that of the mean temperature of the growing season. Experience derived from the failure of the grape crop of 1864 and 1865, over wide regions deficient in humidity, and its success in others where this element must have been abundant, have set its value in a clearer light than heretofore.

In seasons not marked by extreme fluctuations of atmospheric humidity, and accompanying reductions of temperature in midsummer, the isotherms which bound the grape-growing belts, as heretofore described, limiting the regions adapted to certain varieties of grapes, may still be esteemed as normally correct and reliable; but in seasons of exceptional character, when extremes of humidity occur, and, with them, extreme high temperatures followed by great reduction of atmospheric moisture, (and oftentimes accompanying sudden de cline during the night to near the freezing point,) such isotherms cease to be the guiding clews to the regions adapted to any special variety of grape, or, indeed, to indicate that any grape can be therein successfully cultivated. There are few physical laws which can be realized with mathematical exactness, but they are generally approximations, more or less false, in each particular case. "These laws are ideal truths towards which nature tends, but which are never fully reached. Even as respects the law of gravitation, there always have been residual phenomena unexplained by the law; and so, probably, there always will be as our generalizations widen towards the great Presence of which all natural phenomena are the direct manifestation."

We have hitherto regarded the conditions of temperature as of primary importance. Though the amount of moisture in the atmosphere of each locality may be of nearly equal value, we have not the data for determining the propor tions of this ingredient demanded for the successful culture of many of our garden and field products.

With regard to the grape, we are better prepared to discuss the question of the climatic value of excessive or diminished relative humidity. The very favor able reception awarded our former efforts, encourages the hope that the present will prove suggestive, if not instructive.

As a necessary consequence of the evaporation continually going on over the entire surface of the earth, the atmosphere at all times contains a proportion of vapor of water, the amount of which is perpetually varying. This amount is almost always below the proportion which experiment has shown to be the greatest degree possible at the observed temperature. It is owing to this circum