Part 54 (1/2)

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.