ORDER 33. ROSaCEae. (ROSE FAMILY.)

_Plants with regular flowers, numerous (rarely few) distinct stamens inserted on the calyx, and 1--many pistils, which are quite distinct, or (in the last tribe) united and combined with the calyx tube. Seeds (anatropous) 1--few in each ovary, almost always without alb.u.men. Embryo straight, with large and thick cotyledons. Leaves alternate, with stipules_, these sometimes caducous, rarely obsolete or wanting.--Calyx of 5 or rarely 3--4--8 sepals (the odd one superior), united at the base, often appearing double by a row of bractlets outside. Petals as many as the sepals (rarely wanting), mostly imbricated in the bud, and inserted with the stamens on the edge of a disk that lines the calyx tube. Trees, shrubs, or herbs.--A large and important order, almost dest.i.tute of noxious qualities, and producing the most valuable fruits.

Very intimately connected with Leguminosae on one hand, and with Saxifragaceae on the other.

I. Ovary superior and not enclosed in the calyx tube at maturity.

[*] Calyx deciduous, without bractlets, pistil solitary, becoming a drupe.

Tribe I. PRUNEae. Trees or shrubs, with simple mostly serrate leaves.

Ovules 2, pendulous, but seed almost always solitary. Style terminal.

1. Prunus. Flowers perfect. Lobes of calyx and corolla 5. Stone of the drupe bony.

[*][*] Calyx mostly persistent; pistils few to many (rarely solitary).

[+] Calyx without bractlets; ovules 2--many.

Tribe II. SPIRaeEae. Pistils mostly 5, becoming 2--several seeded follicles. Shrubs or perennial herbs.

[a.] Calyx short, 5 cleft. Petals obovate, equal.

2. Spiraea. Flowers perfect or dicious. Pods 1-valved. Herbs or shrubs; leaves simple or pinnate.

3. Physocarpus. Pods inflated, 2-valved. Shrub; leaves palmately lobed.

[b.] Calyx elongated, 5-toothed. Petals slender, unequal.

4. Gillenia. Herbs; leaves 3-foliolate.

Tribe III. RUBEae. Pistils several or numerous, becoming drupelets in fruit. Ovules 2 and pendulous, but seed solitary. Perennials, herbaceous or with biennial soft-woody stems.

5. Rubus. Pistils numerous, fleshy in fruit, crowded upon a spongy receptacle.

6. Dalibarda. Pistils 5--10 in the bottom of the calyx, nearly dry in fruit.

[+][+] Calyx lobes mostly with bractlets; ovule solitary.

Tribe IV. POTENTILLEae. Pistils few--many, 1-ovuled, becoming dry achenes. Herbs.

[a.] Styles persistent and elongated after anthesis, often plumose or jointed.

7. Geum. Calyx lobes usually with 5 alternating small bractlets. Stamens and carpels numerous, styles becoming plumose or hairy tails, or naked and straight or jointed.

[b.] Styles not elongated after anthesis, mostly deciduous.

8. Waldsteinia. Petals and calyx lobes 5; small or no bractlets. Stamens numerous. Achenes 2--6; styles deciduous from the base.

9. Fragaria. Flower as in Potentilla. Receptacle much enlarged and pulpy in fruit.

10. Potentilla. Petals 5 (rarely 4) conspicuous. Calyx lobes as many, with an alternating set of bractlets. Stamens and achenes numerous; the latter heaped on a dry receptacle. Styles commonly more or less lateral, deciduous or not enlarging in fruit.

11. Sibbaldia. Petals minute; stamens and achenes 5--10; otherwise as Potentilla.

II. Ovaries inferior or enclosed in the calyx-tube.

Tribe V. POTERIEae. Pistils 1--4, becoming achenes, completely enclosed in the dry and firm calyx-tube, which is constricted or nearly closed at the throat. Herbs with compound or lobed leaves. Petals often none.

12. Alchemilla. Calyx urceolate, bracteolate. Petals none. Stamens 1--4.

Flowers minute, cl.u.s.tered.

13. Agrimonia. Calyx turbinate, with a margin of hooked p.r.i.c.kles.

Stamens 5--12. Flowers yellow, in long racemes.

14. Poterium. Calyx lobes petaloid; tube 4-angled, naked. Petals none.

Flowers densely capitate or spicate.

Tribe VI. ROSEae. Pistils many, becoming bony achenes, enclosed in the globose or urn-shaped fleshy calyx-tube, which resembles a pome. Petals conspicuous. Stamens numerous.

15. Rosa. The only genus. p.r.i.c.kly shrubs with pinnate leaves.

Tribe VII. POMEae. Carpels 2--5, enclosed in and coalescent with the fleshy or berry-like calyx, in fruit becoming a 2--several-celled pome.

Trees or shrubs, with stipules free from the petiole.

[a.] Cells of the compound ovary as many as the styles (2--5), each 2- (rarely several-) ovuled.

16. Pyrus. Pome containing 2--5 papery or cartilaginous carpels.

17. Crataegus. Pome drupe-like, with 1--5 bony stones or kernels. Usually th.o.r.n.y.

[b.] Cells of the compound ovary becoming twice as many as the styles, each 1-ovuled.

18. Amelanchier. Pome usually of 5 carpels; each becomes incompletely 2-celled by a projection from its back; otherwise as Pyrus.

1. PRuNUS, Tourn. PLUM, CHERRY, ETC.

Calyx 5-cleft, the tube bell-shaped, urn-shaped, or tubular-obconical, deciduous after flowering. Petals 5, spreading. Stamens 15--20. Pistil solitary, with 2 pendulous ovules. Drupe fleshy, with a bony stone.--Small trees or shrubs, with mostly edible fruit. (The ancient Latin name.)

-- 1. PRUNUS proper (and CERASUS). _Drupe smooth, and the stone smooth or somewhat rugged; flowers (usually white) from separate lateral scaly buds in early spring, preceding or coetaneous with the leaves; the pedicels few or several in simple umbel-like cl.u.s.ters._

1. P. Americana, Marshall. (WILD YELLOW or RED PLUM.) Tree th.o.r.n.y, 8--20 high; _leaves ovate_ or somewhat obovate, _conspicuously pointed, coa.r.s.ely or doubly serrate; very veiny, glabrous when mature_; fruit nearly dest.i.tute of bloom, roundish oval, yellow, orange, or red, --{2/3}' in diameter, with the turgid stone more or less acute on both margins, or in cultivated states 1' or more in diameter, the flattened stone with broader margins; pleasant-tasted, but with a tough and acerb skin.--Woodlands and river banks, common.

2. P. maritima, w.a.n.g. (BEACH PLUM.) Low and straggling (1--5); _leaves ovate or oval, finely serrate, softly p.u.b.escent underneath_; pedicels short, p.u.b.escent; fruit globular, purple or crimson with a bloom (--1'

in diameter); the stone very turgid, _acute on one edge_, rounded and minutely grooved on the other.--Sea beaches and the vicinity, N. Brunswick to Va. It varies, when at some distance from the coast (N. J. and southward), with the leaves smoother and thinner and the fruit smaller.

3. P. Alleghaniensis, Porter. A low straggling shrub or small tree (3--15 high), seldom th.o.r.n.y; _leaves lanceolate to oblong-ovate, often long-ac.u.minate, finely and sharply serrate_, softly p.u.b.escent when young, glabrate with age; _fruit globose-ovoid, very dark purple with a bloom_ (less than ' in diameter); stone turgid, a shallow groove on one side and a broad flat ridge on the other.--Bluffs of the Alleghany Mts., Penn.