20. Rosaceous Plants. Rosaceae

* Petals four Jive or more.

Fruit consisting of one or more follicles, containing 2-6 seeds, and invested by a dry calyx.

(81) Spiraea - calyx five-cleft; stamens numerous, inserted along with the petals on a disk adhering to the calyx; follicles usually distinct.

†† Fruit composed of numerous (rarely 1-2) small nuts or drupes (one-seeded) invested by a dry calyx.

‡ Fruit and receptacle both dry.

§ Calyx with external bracts, i.e. in two rows.

(82) Potentilla - calyx 8-10-parted, in two rows; stamens numerous; styles withering; fruits numerous, placed upon a flattish receptacle.

(83) Sibbaldia - calyx ten-parted, in two rows; stamens five; styles withering; fruits five to ten.

(84) Geum - calyx ten-cleft, in two rows; stamens numerous; fruits numerous, tipped with the persistent jointed styles, hooked at the joint.

§§ Calyx without external bracts.

(85) Dryas - calyx 8-9-cleft, in one row; stamens numerous; fruits numerous, tipped with the persistent hairy styles, which are straight at the extremity.

(86) Agrimonia - calyx five-cleft, the tube turbinate, armed with hooked bristles above, and contracted at the throat; stamens fifteen, inserted with the petals into a glandular ring in the throat of the calyx; nuts two, included in the dry tube of the calyx; style terminal.

‡‡ Fruit dry, receptacle succulent.

(87) Fragaria - calyx ten-parted, in two rows; stamens numerous; receptacle large, succulent, pulpy, deciduous; style lateral near the base of the nut.

‡‡‡ Fruit succulent, receptacle dry or spongy.

(88) Rubus - calyx concave or flattish, five-parted; stamens numerous; styles nearly terminal; carpels numerous, succulent, drupaceous, placed upon a spongy receptacle.

††† Fruit formed of numerous small dry nuts enclosed in the fleshy tube of the calyx, ivhich is contracted at the orifice.

(89) Rosa - calyx urceolate, contracted at the mouth, ultimately fleshy, five-cleft; stamens numerous, inserted with the petals on the rim of the tube of the calyx.

** Petals none. † Stamens four.

(90) Sanguisorba - calyx four-cleft, with two or three external scales at its base, the tube quadrangular; stamens four, opposite to the segments of the calyx.

†† Stamens from twenty to thirty.

(91) Poterium - flowers monoecious or polygamous; calyx fourcleft, with three external scales at its base, the tube quadrangular.

21. Crassulaceous Plants. Crassulaceae

* Stamens as many as the petals, alternating with them.

(92) Tillaea - sepals, petals, stamens, and carpels three or four.

** Stamens twice as many as the petals, and opposite to them.

(93) Cotyledon - sepals five; petals cohering in a tubular fivecleft corolla; stamens ten, inserted on the corolla; hypogynous scales concave.

(94) Sedum - sepals and petals five, rarely four, distinct; stamens ten, rarely eight; hypogynous scales entire.

(95) Sempervivum - sepals and petals 6-20, usually 10-12; stamens twice as many; hypogynous scales laciniated.