long, roundish, two ranked; awn from below the top of the valves.

32. ARUNDO. Calyx two valved; corolla woolly at the base, awnless.

C. Flowers spiked on a long slender receptacle.

33. LOLIUM. Calyx one valved, many flowered. 34. TRITICUM. Calyx two valved, many flowered.

35. ELYMUS. Involucre four leaved, two flowered; flower compound.

36. HORDEum. Involucre six leaved, three flowered; flowers simple.

37. LECHEA. Corolla three petalled; calyx three leaved; capsule three celled, three valved. 38. MOLLUGO. Corolla none; calyx five leaved; capsule three celled.

B. Flowers superior.

39. PROSERPINACA. Corolla none; calyx three parted; seed one, three celled.

32

IRIS VIRGINICA. L.

40

TRIANDRIA.

MONOGYNIA.

13. IRIS.

Virginian Iris. Common blue flag or flower de luce.

Flowers beardless; leaves ensiform; stem acute on one side; segments of the stigma turned backward.

A principal ornament of meadows and wet grounds, its large blue flowers appearing in June. Stem from one to three feet high, compressed, with one side sharper than the other. Leaves sword shaped, a little curved at the point. Germs obtusely three cornered with flat sides. Outer petals revolute, more than twice the size of the inner.-Perennial,

IRIS GRACILIS. (mihi).

Boston Iris.

Iris imberbis ; foliis linearibus; caule tereti, plurifloro; germinibus trigonis, lateribus bisulcis. Flowers beardless; leaves linear; stem round, many flowered; germs triangular, twice grooved on the sides,

Root fleshy, sending out short runners from which new plants arise; stem round, smooth, slender, from one to two feet high, branching at top, bearing several alternate leaves, and from two to eight flowers. Leaves linear, erect, sheathing at their base. Bractes or involucres close, becoming dry. Peduncles flattened on the inside, varying in their proportions to the bractes, but commonly longer. Outer petals slender, spreading, purple at the edge, yellow and veined in the middle, the yellow portion much greater than in the last species. Inner

petals lanceolate, slightly emarginate. Germs oblong, three sided; sides with two deep parallel grooves, the whole representing a cylinder with three smaller ones attached to its sides. As the germ enlarges the distance between the two furrows does not increase, and they are nearly obliterated in the capsule, which is triangular and turgid with its three row of seeds.

Found at South Boston and Cambridge in the same places with Iris Virginica, but much less frequent.-June-Perennial.

14. XYRIS.

XYRIS JUPICAI. Mich.

Fellow eyed grass.

Leaves linear, somewhat obtuse; scape near the head dilated, two edged; scales rounded. Mich. abr.

Root bulbous; leaves grassy, shorter than the scape; scape erect, two edged, twisted, a little widened at top. Heads roundish, rather acute, supporting a number of small yellow florets projecting out of the scales, hairy within, and consisting of three ovate, crenate petals.-Meadows.-July, August.-Perennial.

15. SCHOENUS.

SCHOENUS ALBUS. L.

White headed bog rush.

Culm three sided, leafy; flowers fascicled; leaves setaceous.

A smooth, grassy plant, with white heads of flowers. Stem half a foot or more in height, three sided, mostly smooth. Leaves mostly belonging to the stem, alternate, sheathing, the sheaths tubular or entire. Flowers in fascicles on footstalks, terminal and axillary, erect. Glumes white, afterward becoming brownish. Seeds surrounded with short hairs.-In low woods and swamps. Brighton.-July.-Perennial.

16. CYPERUS.

CYPERUS SPATHACEUS. L.

Sheathed Cyperus.

Culm round, leafy; leaves alternate, with entire sheaths; racemes axillary and terminal.

The lower

A tall leafy grass. Stem smooth, hardly three sided, covered with numerous short, flat, smooth, spreading leaves, proceeding from sheaths which are perfectly entire or tubular, the part opposite the leaf ending in a rounded point. leaves, not the sheaths, are deciduous. Racemes mostly axillary. Peduncle compressed, bearing from five to eight alternate, sessile, narrow spikelets of about six flowers. Glumes two ranked. Seeds surrounded with hairs.-Borders of ponds and rivers.-August.-Perennial.

17. SCIRPUS.

SCIRPUS TRIQUETER.

Mich.

Triangular club rush.

Culm leafless, three sided; spikelets lateral, shorter than the point, sessile, conglomerate, oblongovate. Mich. abr.

A naked, triangular rush, two or three feet in height. Culm straight, smooth, acute angled and sharp pointed. Spikes few, in a lateral bunch near the top, mostly sessile, crowded, reddish. Glumes carinate pointed, with a dilated, lacerated

margin. Salt marshes.-July, August.-Perennial.

In this variety, the spikes are few in number, mostly sessile, and generally two inches or more below the top of the stem. It corresponds with the figure of Plukenet, but hardly with that of Sowerby.

SCIRPUS MARITIMUS. L.

Sea club rush.

Culm triangular, panicle clustered, leafy, terminal; glumes pointed, torn into three segments. Sm. Syn. SCIRPUS MACROSTACHYUS. Lam. Muhl.

Culm erect, smooth, one or two feet high, leafy at base. Leaves linear, acute, rough on the margin. Bractes or floral leaves several, very unequal in length. Panicle resting on these, crowded, consisting of large sessile and pedunculated spikes, ovate, conspicuous by their dull chesnut colour and yellow anthers. The glumes are ovate, shining, slightly carinated, divided into three small segments at tip, the middle one of which is prolonged into a short, setaceous awn.-Salt marshes and ditches.-July.-Perennial.

SCIRPUS RETROFRACTUS. L.

Burr rush.

Culm triangular; umbel simple; spikelets divaricated.

A conspicuous grass in meadows and low grounds. Stem erect, with three acute angles. Leaves smooth, with a rough edge. Floral leaves several, very long, unequal. Rays of the umbel unequal, with terminal spikes. Spikelets numerous, linear-subulate, closely imbricate, sessile, surrounding their common stalk, and inserted nearly at a right angle with it.-July, August.-Perennial.

SCIRPUS ACUTUS. Muhl.

Pointed bullrush.

Culm round, leafless, equal; spikes several, below the top, oblong, somewhat umbelled.

ހ

This nearly resembles the large bullrush, (Scirpus lacustris,) but differs in its fructification, which is lateral, never terminal. Culm erect, round, smooth, naked, filled with light, spongy pith, often spotted, five or six feet high, uniform in size for the greater part of its length, ending in an acute point.