116. Liliaceæ (p. 517). Flowers perfect, 6-androus, the regular perianth corolla-like (diœcious in Smilax, dimerous in Maianthemum, the outer divisions herbaceous in Trillium). Fruit a 3-celled capsule or berry. 117. Pontederiaceæ (p. 535). Aquatic, with more or less irregular perfect flowers from a spathe; perianth corolla-like. Stamens 3 or 6, mostly unequal or dissimilar. Capsule 1-celled or imperfectly 3-celled. 118. Xyridaceæ (p. 536). Rush-like, scapose. Flowers capitate, perfect, 3-androus, the calyx glumaceous. Capsule 1-celled. 119. Mayaceæ (p. 537). Moss-like aquatic. Flowers perfect, axillary, solitary, 3-androus; calyx herbaceous. Capsule 1-celled. 120. Commelinaceæ (p. 538). Flowers perfect, regular or somewhat irregular, with 3 more or less herbaceous persistent sepals and 3 fugacious petals. Stamens 6 or some sterile. Capsule 2--3-celled. 127. Eriocauleæ (p. 566). Scapose aquatic or marsh plants, with linear leaves and dense heads of monœcious (rarely diœcious) minute flowers. Corolla tubular or none. Capsule 2--3-celled, 2--3-seeded. [+] 2. Perianth small, of 6 equal persistent glumaceous segments; flowers perfect; ovary compound. 121. Juncaceæ (p. 539). Rush-like. Stamens 3 or 6. Capsule 1- or 3-celled, 3-valved. [+] 3. Flowers without chaffy glumes, the perianth none or reduced to bristles or sepal-like scales; flowers often monœcious or diœcious; carpels solitary or united. [++] Flowers capitate or upon a spike or spadix, with or without a spathe. 122. Typhaceæ (p. 547). Marsh or aquatic plants, with linear leaves, and monœcious flowers without proper perianth, in heads or a naked spike. 123. Araceæ (p. 548). Flowers perfect or monœcious upon the same spadix, rarely diœcious, with 4 or 6 scale-like sepals or none. [++][++] Flowers very minute, one or few from the margin of a floating disk-like frond. 124. Lemnaceæ (p. 551). Plants very small, green, mostly lenticular or globose. [+] 4. Perianth of 4 or 6 segments, the inner often petaloid, or none; carpels solitary or distinct (coherent in Triglochin); seeds without albumen; aquatic or marsh plants, often monœcious or diœcious. 125. Alismaceæ (p. 553). Perianth of 6 segments, the inner petal-like. 126. Naiadaceæ (p. 557). Perianth-segments herbaceous or none. [+] 5. Flowers in the axils of chaffy scales or glumes arranged in spikes or spikelets, without evident perianth; stamens 1--3; ovary 1-celled, 1-seeded; seed albuminous. 128. Cyperaceæ (p. 567). Scales single. Perianth none or replaced by bristles. Anthers basifixed. Fruit a triangular or lenticular achene. Stem solid, often triangular, with closed sheaths. 129. Gramineæ (p. 623). Glumes in pairs. Perianth replaced by minute scales. Anthers versatile. Fruit a caryopsis. Culm usually hollow, terete; sheaths split to the base. SERIES II. CRYPTOGAMOUS OR FLOWERLESS PLANTS; destitute of stamens and pistils, in fructification producing _spores_ instead of seeds. CLASS III. ACROGENOUS PLANTS.