ræa, Antholyza, Gladiolus, Ixia, Dilatris, Wachendor. fia, Commelina, Hippocratea, Loeflingia, Willichia, Tamarindus, Callisia, Rumphia, Cneorum, Xyris, Comocladia, Olax, Rotala, Ortegia, Polycnemum, Schoenus, Cyperus, Scirpus, Eriophorum, Nardus, Lygeum, Kyllingia, Fuirennia, and Pommereulla.

***
**

NARCISSUS triandrus belongs to this order.

DIGYNIA.

TWO FEMALES.

To this order belong the following genera, viz. Bobartia, Panicum, Cornucopiæ, Aristida, Alopecurus, Phleum, Muhlenbergia, Phalaris, Paspalum, Milium, Agrostis, Dactylis, Stipa, Lagurus, Saccharum, Aira, Melica, Uniola, Briza, Poa, Festuca, Bromus, Avena, Arundo, Anthistiria, Secale, Triticum, Rottboellia, Hordeum, Elymus, Lolium, and Cynosurus.

TRIGYNIA.

THREE FEMALES.

THIS order contains the following genera, viz. Holosteum, Polycarpon, Lechea, Eriocaulon, Montia, Mol

lugo, Minuartia, Queria, Koenigia, Triplaris, and Proserpinaca.

CHARACTER.

THIS is, in various respects, a natural class. The first order is less natural than the second. The genus Valeriana, or Valerian, is an irregular one, some of the species having only one, while others have three, and some four stamens. Iris, Crocus, Moræa, Antholyza, Gladiolus, Ixia, and some others, have considerable affinities to each other. They, together with Commelina, Tradescantia, Pontederia, &c. constitute Linnæus's sixth order, called Ensata; a name given to them, by the Swedish naturalist, on account of the form of their leaves, which is thought to resemble that of a sword*. This order likewise contains some grasses, such as Schoenus, Cyperus, &c. But the second order is almost entirely made up of plants of this family, many of which are highly important to mankind. The Sugar-cane is the Saccharum officinarum. The Avena, or Oat, the Secale, or Rye, the Triticum, or Wheat, the Hordeum, or Barley, not to mention others, are among the number of the most important vegetables with which we are acquainted. I have taken notice of some of the most essential characters of the grasses, in former parts this workt.

SEVERAL of the plants of the third order of this class, are arranged by Linnæus in his twenty-second natural order, the order Caryophyllei.

In a medical point of view, the class Triandria is much less important to mankind than several of the other classes of the system. Nevertheless, this class contains some useful articles of the materia medica (properly so called), such as the Valeriana officinalis, or Valeri. an; the Crocus sativus, or Saffron; different species of Iris, or Flag; the "fever-cooling" Tamarind*, &c.

MANY of the genera of this class are natives of the United-States.

FOR an illustration of the class Triandria, see Plate X.

CLASS IV.

TETRANDRIA.

FOUR MALES.

THE fourth class is denominated TETRANDRIA†. This class contains hermaphrodite flowers, which are furnished with four stamens, or male organs, which are all of an uniform length. By this latter circumstance, the plants of the class Tetrandria are distinguished from those of the XIVth class, or Didynamia: for this last class comprehends plants that have also four stamens,

• Thomson.

+ From Toσages, four,

two of which are long, and two short. See DIDYNA

MIA.

THE class Tetrandria is subdivided into three orders, viz. MONOGYNIA, DIGYNIA, and TETRAGYNIA.

MONOGYNIA.

ONE FEMALE.

THIS order contains the following genera, viz. Protea, Globularia, Hydrophylax, Cephalanthus, Dipsacus, Scabiosa, Knautia, Allionia, Aquartia, Callicarpa, Scoparia, Bartonia*, Centunculus, Plantago, Polypremum, Buddleia, Exacum, Penaea, Blaeria, Pavetta, Ixora, Petesia, Catesbaca, Mitchella, Hedyotis, Oldenlandia, Mannettia, Sanguisorba, Houstonia, Scabrita, Rubia, Galium, Asperula, Sherardia, Spermacoce, Knoxia, Diodia, Crucianella, Siphonanthus, Epimedium, Rhacoma, Ptelea, Samara, Fagara, Ammannia, Banksia, Hartogia, Trapa, Cissus, Cornus, Ludvigia, Santalum, Rivina, Camphorosma, Alchemilla, Dorstenia, Cometes, Sirium, Isnardia, and Elæagnus.

***
**

To this order belong various species of plants, the genera of which are placed by Linnæus, in other classes

Bartonia of Professor Willdenow.

of his system. I shall mention the following, viz. Valeriana sibirica, Swertia corniculata, S. dichotoma, some species of Gentian and Euonymus, Coffea occidentalis, Peplis tetrandra, Cardamine hirsuta, Corchorus Coreta, Convallaria bifolia, Thesium alpinum, Melastoma tetrandrum, Hillia tetrandra, &c. &c.

DIGYNIA.

TWO FEMALES.

THIS order contains the following genera, viz. Buffonia, Hypecoum, Hamamelis, Cuscuta, Aphanes, Cruzita, and Gomozia.

TETRAGYNIA.

FOUR FEMALES.

THIS order contains the following genera, viz. Ilex, Coldenia, Sagina, Tillæa, Myginda, Potamogeton, and Ruppia.

CHARACTER.

THE class Tetrandria has some claim to the character of a natural class of plants. Several of the genera of the first order, such as Protea, Banksia, Globularia, Cephalanthus, Dipsacus, Scabiosa, &c. &c. form a part of Linnæus's forty-eighth order, the order Aggregata.