171b. Stamens attached at the very base of the corolla =CAMPANULACEAE=, p. 112.

172a. Plants of the composite type, with several or many small flowerets closely aggregated into dense heads subtended by a calyx-like involucre of small bracts --173.

172b. Flowers solitary or cl.u.s.tered, but not in involucred heads --174.

173a. True composites, without a normal calyx =COMPOSITAE=, p. 113.

173b. A normal calyx with each floweret; leaves compound with 3 leaflets =LEGUMINOSAE=, p. 58.

174a. Flowers irregular, i. e., the conspicuous lobes of the perianth unlike in size or shape --175.

174b. Flowers regular --185.

175a. Stamens 2 or 4 =SCROPHULARIACEAE=, p. 101.

175b. Stamens 5 --176.

175c. Stamens 6 --181.

175d. Stamens 8; leaves simple =POLYGALACEAE=, p. 65.

175e. Stamens 10; leaves usually compound =LEGUMINOSAE=, p. 58.

175f. Stamens more than 10 --183.

176a. Petals separate --177.

176b. Petals united --179.

177a. Flowers greenish or purplish, in a panicle =SAXIFRAGACEAE=, p. 49.

177b. Flowers white or purplish, in compound umbels =UMBELLIFERAE=, p. 80.

177c. Flowers solitary, or in few-flowered cl.u.s.ters --178.

178a. Flowers blue, yellow, or white, in spring =VIOLACEAE=, p. 75.

178b. Flowers red-orange or yellow, in summer =BALSAMINACEAE=, p. 71.

178c. Flowers small and greenish, in spring 1a, in =VIOLACEAE=, p. 75.

179a. Anthers united; stamens protruding from the very irregular corolla =LOBELIACEAE=, p. 113.

179b. Anthers separate; corolla almost regular --180.

180a. Corolla rotate; some or all filaments hairy 2, in =SCROPHULARIACEAE=, p. 101.

180b. Corolla funnel-form, dull yellow and purple; filaments not hairy 12a, in =SOLANACEAE=, p. 101.

180c. Corolla funnel-form, blue or violet; filaments not hairy 7b, in =BORAGINACEAE=, p. 94.

181a. Leaves compound or dissected =FUMARIACEAE=, p. 41.

181b. Leaves simple --182.

182a. Flowers solitary =ARISTOLOCHIACEAE=, p. 25.

182b. Flowers in spikes, heads, or racemes =POLYGALACEAE=, p. 65.

183a. Leaves truly compound --184.

183b. Leaves palmately cleft; flowers 15 mm. wide or larger 6a, in =RANUNCULACEAE=, p. 36.

183c. Leaves irregularly cleft; flowers about 5 mm. wide =RESEDACEAE=, p. 48.

184a. Petals prolonged backward into hollow spurs 6b, in =RANUNCULACEAE=, p. 36.

184b. Petals not prolonged into spurs =CAPPARIDACEAE=, p. 47.

--185--

185a. Perianth consisting of one circle of parts only (usually considered to be the calyx) --186.

185b. Perianth consisting of both calyx and corolla --192.

186a. Leaves with sheathing stipules encircling the stem above the base of every leaf =POLYGONACEAE=, p. 25.

186b. Leaves without sheathing stipules --187.

187a. Leaves entire --188.

187b. Leaves toothed, lobed, or compound --190.

188a. Stamens 5 =SANTALACEAE=, p. 24.

188b. Stamens 6 --189.

188c. Stamens 10 =PHYTOLACCACEAE=, p. 30.

189a. Perianth-lobes 3; perianth-tube curved =ARISTOLOCHIACEAE=, p. 25.

189b. Perianth-lobes 6, spreading 4a, in =LILIACEAE=, p. 11.

190a. Stamens 5 =UMBELLIFERAE=, p. 80.

190b. Stamens 6 --191.

190c. Stamens more than 6 =RANUNCULACEAE=, p. 35.