Differing essentially from both of these, Arachis hypogaca has but one form of flower which is sessile and remains so. It is a growth from the base of the ovary itself which is prolonged until the ovary is pushed into the ground. This growth is technically known as a gynophore. Ovaries which are hindered by any circumstance from reaching the ground do not produce fruit.

Seven species of Arachis are now recognized. These are: A. pusilla, A. prostrata, A. villosa, A. glabrata, A. marginata, A. tuberosa and Arachis hypogaea, all perennial with the exceptions of A. hypogaca and A. pusilla. Of these species six are found only in Brazil. The remaining one, Arachis hypogaea is cultivated at the present time throughout the warmer regions of the globe.

Little is known with certainty concerning the earlier history of Arachis. The fact that all but one of its species are confined to Brazil would seem an indication that it is a native of that country, and in fact De Candolle ascribes its origin to that place. Other authors think it to be a native of Africa, as its importance there as food is so great and its cultivation so general. Still others hold the opinion that it has a Japanese or Chinese origin. Opposing this opinion are the facts that no allusion is made to this plant in the older literature of those countries and that the fruit is not produced there in any great quantities.

Sloan, writing in the latter part of the sixteenth century, speaks of it as having been carried to the West Indies from Guinea in slave ships as food for the slaves, and says it was taken to Guinea from Peru. Oviedo, writing in 1547, describes Arachis under the name Mani and states that it is very common in the gardens of the West Indies. From the name Mani is derived the name which the plant now bears in Cuba, Mandubi or Mandobi. Jean de Lery, in 1578, writing a history of travel in Brazil, speaks of Arachis as Manobi. The author of the Noticia do Brasil (1589) speaks of the plant under the name Amandao (large Mandel). Rumph described the plant, giving it the name Chamaebalanus Japonicus. Parkinson, writing about 1648, described the American Arachis and called it Arachis hypogais Americanus.

It is estimated that the yearly production of peanuts in this country is about 4,000,000 bushels and that this constitutes about one-sixth of the production of the entire world. This amount is con

tributed almost entirely by Virginia, Georgia, Tennessee and North Carolina, Virginia ranking first in its production. Notwithstanding this large amount supplied to our market and the high nutritient value of the seed, the peanut is nowhere used in the United States as an article of food-as it is used in other countries. Some effort has been made, however, to show how valuable it would prove if so utilized. In Germany experiments have been made with reference to adopting it as an article of diet for the army; and it is said to be already in use there as a dietetic treatment for diabetes.

The following analysis is taken from statistics furnished by German authorities and will serve to show what valuable propererties it posesses as a food constituent:

The oil of this fruit is used as a substitute for olive oil, which it much resembles, and to which it is even sometimes preferred. It is also used as a lubricant and in the manufacturing of toilet soap.

Notwithstanding the fact that the fruit of Arachis formed so important an article of commerce and that, on account of its utilitarian value, it was so widely cultivated, it has been correctly described only in comparatively recent times.

Piso, writing in 1658, says only of the flower that it is small and yellow, and states that the fruit originates on the root-fibres. The later botanists up to the year 1805 all described the structure of the flower erroneously. The long stem-like calyx was assumed to be a flower stalk even by those botanists who had access to the living plants. In 1805 Poiteau published the first correct description of the structure of the flower. Robert Brown afterward confirmed Poiteau's description in the appendix to Tuckey's Narration of an Expedition to the Zaire, in 1816. Notwithstanding the work of Poiteau, Bentham as late as 1839 writes of Arachis as a plant with dimorphous flowers. One form, with calyx and corolla, which are always sterile, the fertile flowers having "neither calyx, corolla nor stamens, but from between two bracteolae, similar to those which are found at the base of the sterile flowers proceeds a stiff rigid stipe or torus, which is speedily reflexed and elongated,

and is terminated by what appears to the naked eye a short point. Examined under a glass this point discloses at its extremity a truncated, somewhat concave and dilated stigma."

Hugh M. Neisler, acting upon the supposition that Bentham's statements were correct, made some observations upon the fructification of Arachis which convinced him that, in his own words, "The flowers of Arachis are all petal-bearing and all fertile." (Silliman's Am. Journal of Science and Art, 2d series, 19: 1855). Bentham remained unconvinced and published a reply in Hooker's Journal of Botany and Kew Garden Miscellany, 7: 1855. It is difficult to understand how Bentham could have persisted in his mistake, as he did, in the face of so much evidence.

It requires no very expert examination of the plant to be convinced that what he mistook for a cleistogamic flower is the naked ovary after the flower parts have fallen away; and that what he describes as the sessile stigma of the barren ovary is the scar left by the deciduous style.

As to the affinities of Arachis no satisfactory conclusion is yet attained. Linnaeus placed it next to Cicer; Persoon, nearer Anthyllis; Jussieu, between Ononis and Anthyllis. De Candolle, classifying it according to the character of its embryo, place it among his Geoffroyae, but at the same time recognizing how little it conforms in other respects to these plants, suggested its forming together with Voandzeia a distinct tribe. Robert Brown says that Arachis and Cercis possess straight embryos in common with the Caesalpinieae and Mimoseae and in which respect they differ from all of the Papilionaceae. Bentham, adhering to his opinion that Arachis possessed dimorphous flowers, points out a resemblance to Stylosanthes, but finds an important difference from the group Hedysareae, of which Stylosanthes is a member, in the unarticulated legume. He finds Arachis not at all similar to Voandzeia. Pending a harmonizing of these conflicting opinions Arachis is usually accepted among the Papilionaceae.

General Description of the Plant.

Arachis hypogaca is a low annual plant, with one upright flowerless branch surrounded by decumbent spreading branches, upon which the flowers are borne. The stem is cylindrical and smooth,

at the base becoming angular and slightly hairy above. The leaves are alternate and pinnate with two pairs of nearly sessile leaflets, the inferior pair of which are nearly elliptical and the superior pair are cuneate and noticeably larger. The leaflets are furnished with pulvini which comprise the entire stalklet (about 1 mm. in length). The primary petiole is also furnished with a pulvinus and with two adnate stipules which partly clasp the stem. The straight tap root gives off numerous lateral roots.

Nearly all of the roots examined bore quantities of the small tuber-like swellings which are a much discussed characteristic of the roots of the Leguminosae. These occur indifferently on the main and lateral roots.

The flowers develop in the axils of the leaves. They are sessile, but with a long calyx, which may easily be mistaken for a peduncle. This calyx varies from 3 to 14 mm. in length, is cylindrical, two-lipped, hairy and with two bracts at its base. The upper lip is two-toothed. The corolla is papilionaceous and yellow. The stamens are monadelphous and inserted in the calyx. They are ten in number and of two kinds, one with long two-celled anthers dehiscing laterally, and one with nearly spherical one-celled anthers.

The ovary is superior, small, conical and one-celled. The style is inserted a little to one side of the apex of the ovary. It is long, cylindrical, exceedingly slender, hairy for a short distance along one side from the stigma, and is terminated by a flat stigmatic surface. After fertilization the gynophore begins its growth. The flower parts fall off; sometimes the style may be seen as a brown hair-like appendage to the ovary after the flower falls. More frequently it is thrown off with the flower.

The ovary

becomes tipped with a hardened and brown point. The gynophore curves so that it points towards the earth. The growth of the gynophore continues until the ovary has penetrated the earth for some distance. The ovary then begins to swell to form the pod. The part of the gynophore under ground thickens and. develops hairs from its epidermal cells which are in every way similar to root hairs.

The fruit develops only under ground. It is a one-celled pod bearing from one to three, or according to Kurtz, sometimes as many as seven seeds. The number is usually two. The pod is inde

hiscent. The seeds have a purplish brown membrane and no albumen. The embryo is straight. The large, fleshy cotyledons are furnished with pulvini and are exceedingly rich in oil.

General Observations on the Plants Studied,

The following study was made with plants raised during two successive summers in Englewood, N. J.; Lawrence, L. I., and in Potsdam and Buffalo, N. Y. In New Jersey and on Long Island the plants thrived and produced fruit. The seeds planted in richer soil in northern New York produced healthy looking, well-grown plants with flowers but no fruit developed. The plants grow best in a dry sandy soil, and a warm, at least temperate, climate. Under favorable conditions of weather fruit was obtained from seeds planted in Lawrence within two months. From two to three months is usually required. Plants of a crop raised in Lawrence when pulled up during the early part of October were found to bear a quantity of tubers on their roots. On other plants of the same crop examined in November no tubers were found.

In the nyctotropic movement of the leaves, which has already been described by Darwin in his "Power of Movement in Plants," the main petiole sinks downward; the leaflets twist downward and backward so that the lower surfaces of each pair are applied to each other. In this position they form a little packet shutting around the petiole, with the superior pair closed over the inferior and the tips pointing upward. The leaves vary their positions. on the stem during the day in such a way as to keep their upper surfaces inclined toward the sun. When a leaf was separated from the stem so that the water supply was cut off while evaporation was going on it was discovered that the loss of water made itself apparent first in the upper half of the pulvinus of the leaflets.

When cut at night or at four p. m. the movement was quicker, probably because the water in the cells of the upper half of the pulvini had already begun to lessen in quantity. The leaves of some stems cut in the morning slept after about one-half hour; others slept at once. The leaves of stems cut on a hot day slept more quickly than those cut on a cool day; those cut at about four in the afternoon more quickly than those cut in the morning.