129a. Flowers in dense cottony heads; plants more or less white-woolly 79, in =COMPOSITAE=, p. 120.

129b. Pistillate flowers in an ovoid spiny involucre, ripening into a bur 3a, in =COMPOSITAE=, p. 114.

129c. Flowers minute, subtended by palmately cleft axillary bracts 1a, in =EUPHORBIACEAE=, p. 66.

129d. Plants without any of the preceding characters --130.

130a. Plants with milky or colored juice 10, in =EUPHORBIACEAE=, p. 67.

130b. Plants with tendrils, at least on the upper leaves 4a, in =LILIACEAE=, p. 11.

130c. Plants of nettle-like character, with stinging hairs 8b, in =URTICACEAE=, p. 24.

130d. Plants with sheathing stipules, surrounding the stem above the base of each leaf =POLYGONACEAE=, p. 25.

130e. Plants with smooth, pale, juicy, almost translucent stems 12a, in =URTICACEAE=, p. 24.

130f. Plants without any of the preceding structures or habits --131.

131a. Flowers axillary, solitary or in few-flowered cl.u.s.ters --132.

131b. Flowers in terminal, or terminal and axillary cl.u.s.ters --138.

132a. Leaves linear =CHENOPODIACEAE=, p. 28.

132b. Leaves of a broader shape than linear --133.

133a. Flower-cl.u.s.ters with bracts as long as or longer than the flowers --134.

133b. Flowers without conspicuous bracts --135.

134a. Leaves broadest below the middle 8a, in =URTICACEAE=, p. 24.

134b. Leaves broadest above the middle 2, in =AMARANTHACEAE=, p. 30.

135a. Princ.i.p.al leaves 3 cm. long or more --136.

135b. Princ.i.p.al leaves 2.5 cm. long or less --137.

136a. Flowers nodding in the axils of the leaves 1a, in =VIOLACEAE=, p. 75.

136b. Flowers erect in the axils 2a, in =ONAGRACEAE=, p. 78.

137a. Leaves narrowly oblong 1a, in =HALORAGIDACEAE=, p. 79.

137b. Leaves roundish and somewhat heart-shape 12a, in =SAXIFRAGACEAE=, p. 50.

138a. Flowers in racemes or simple spikes --139.

138b. Flowers in panicles or other branched cl.u.s.ters --141.

139a. Leaves toothed or lobed 52b, in =CRUCIFERAE=, p. 46.

139b. Leaves entire --140.

140a. Flowers sessile; leaves heart-shape =PIPERACEAE=, p. 19.

140b. Flowers pedicelled; leaves obovate 8b, in =PRIMULACEAE=, p. 87.

141a. Individual flowers distinct from each other, on pedicels --142.

141b. Individual flowers crowded in close cl.u.s.ters, or separate and sessile --143.

142a. Leaves finely serrate 3b, in =CRa.s.sULACEAE=, p. 49.

142b. Leaves entire 1b, in =CISTACEAE=, p. 74.

143a. Flower-cl.u.s.ters mingled with sharp-pointed bracts =AMARANTHACEAE=, p. 30.

143b. Flower-cl.u.s.ters without bracts, or (rarely) with bracts which are not sharp-pointed =CHENOPODIACEAE=, p. 28.

--144--

144a. Juice not milky --145.

144b. Juice milky; apparent flowers consisting of a few white or colored petal-like bracts, inclosing a few inconspicuous flowers without petals. In some of them a 3-lobed ovary with 3 styles may be plainly seen =EUPHORBIACEAE=, p. 66.

145a. Plants of the composite type, with several or many small flowerets closely aggregated into a dense head subtended by a calyx-like involucre of small bracts --146.

145b. Flowers solitary or in cl.u.s.ters, but not in involucred heads --147.

146a. Leaves compound with 3 leaflets; stipules present =LEGUMINOSAE=, p. 58.

146b. Stipules none =COMPOSITAE=, p. 113.

147a. Leaves compound or deeply lobed --148.

147b. Leaves simple and not deeply lobed --154.

148a. Flowers irregular =LEGUMINOSAE=, p. 58.

148b. Flowers regular --149.

149a. Petals 3 =LIMNANTHACEAE=, p. 68.

149b. Petals 4 --150.

149c. Petals 5 or more --151.