Filaments distinct............................ 179

Asclepiadaceae. - Plants with milky juice. Anthers adhering to the stigmas. Filaments monadelphous. Flowers in umbels............................ 179

+ + Ovary 4 -lobed around the base of the style. Mentha, in Labiatae. - Stamens 4. Leaves opposite, aromatic..... 160

Borraginaceae. - Stamens 5. Leaves alternate......... 167

+ + + Ovary 1-celled; the seeds on the walls.

Hydrophyllaceae. - Stamens 5, usually exserted. Style 2-cleft. Leaves lobed and sometimes cut-toothed. 171

Gentianaceae. - Leaves entire and opposite; or (in Menyanthes) of 3 leaflets......................... 176

+ + + + Ovary with 2 or more cells.

Aquifoliaceae. - Shrubs. Corolla almost polypetalous.

Calyx minute. Fruit a red berry-like drupe.

Parts of the flower chiefly in fours or sixes..... 145

Plantaginaceae. - Stamens 4. Pod 2-celled. Flowers in a close spike.................................. 148

Verbascum, inCorolla nearly regular. Flowers in a long terminal spike. Stamens 5; the filaments, or some of them, woolly....................... 151

Polemoniaceae. - Style 3-cleft. Corolla salver-shaped, with a long tube. Pod 3-celled, few-seeded; seeds small. .,..,..,...,,........ ,.,,,..,... 172

Convolvulaceae. - Style 2-cleft. Pod 2-celled, generally 4-seeded; seeds large. Chiefly twining or trailing plants.................................... 173

Solanaceae. - Style single. Pod or berry 2-celled, many-seeded ....................................... 174

* * * * Stamens fewer than the lobes of the corolla; the corolla mostly irregular or 2-lipped.

Labiatae. - Ovary 4-lobed around the base of the style. Stamens 4 and didynamous, or occasionally only 2 with anthers. Stem square................. 160

Ovary 4-celled, but not lobed; the style rising from the apex. Or, Ovary 1-celled and 1-seeded. Stamens didynamous................. 158

Lentibulariaceae. - Aquatics. Stamens 2. Ovary 1celled, with a free central placenta............. 149

Orobanchaceae - Parasitic herbs, without green foliage. Ovary 1-celled, with many seeds on the walls. Stamens didynamous.......................... 150

Scrophulariaceae. - Ovary 2-celled, with many seeds.

Stamens didynamous, or only 2................ 151

Stamens 2, the anther-cells separated.

Ovary flat, 2-celled, 4-seeded. Aquatics........ 159

Corolla (and sometimes calyx also) wanting.

A. Flowers not in catkins.

* Calyx and corolla both wanting.

Piperaceae. - Flowers white, in a dense terminal spike, nodding at the end. Carpels 6 or 4, nearly separate.......................................... 182

Ceratophyllaceae. - Immersed aquatics, with whorled finely dissected leaves. Flowers monoecious___ 213

* * Calyx superior (i.e., adherent to the ovary).

Saxifragaceae. - Small, smooth herbs, with inconspicuous greenish-yellow flowers. Stamens twice as many as the calyx-lobes, on a conspicuous disk........ 75

Halorageae. - Aquatics. Leaves finely dissected or linear.

Stamens 1-8. Ovary3-4-lobed or (Hippuris)l-celled. 79

Onagraceae. - Herbs, in ditches. Stamens 4. Ovary 4celled, 4-sided................................ 81

Ahistolochiaceae. - Calyx 3-lobed, dull purple inside.

Ovary 6-celled.......... ............... 182

Low plants with greenish-white flowers in terminal clusters. Calyx-tube prolonged, and forming a neck to the 1-celled nut-like fruit..... 195

Elaeagnaceae. - Shrubs with scurfy leaves. Flowers perfect or dioecious. Calyx 4-parted, in the fertile flowers apparently adherent to the ovary, and becoming fleshy in fruit........................ 194

* * * Calyx inferior (plainly free from the ovary).

+ Ovaries more than one and separate from each other.

Ranttncttlaceae. - Calyx present, coloured and petal-like.

Achenes containing several seeds, or only one.... 2

Rutaceae. - Prickly shrubs, with compound transparent-dotted leaves, and dioecious flowers............. 43

+ + Ovary only one, but with more than one cell (except in Glaux).

Crassulaceae. - Herbs, in wet places. Pod 5-celled and 5-horned..................................... 78

Phytolaccaceae. - Herbs. Ovary 10-celled and 10-seeded 183

Herbs. Ovary 3-celled, 3-lobed, protruded on a long pedicel. Juice milky.......... 195

Sapindaceae. - Trees. Ovary 2-celled and 2-lobed. Fruit two 1-seeded samaras joined together. Flowers polygamous................................. 47

Rhamnaceae. - Shrubs. Ovary 3-celled and 3-seeded; forming a berry............................... 45

Ficoideae. - Prostrate herbs with whorled leaves. Ovary 3-celled, many-seeded........................ 86

Urticaceae. - Trees. Leaves simple. Ovary 2-celled, but fruit a 1-seeded samara winged all round. Stigmas 2......................................... 198

Empetraceae. - Low shrubby evergreens with heath-like leaves....................................... 213

Glaux, in Primulaceae. - Herbs. Ovary 1-celled, the placenta central.......................................... 145

+ + + Ovary only one, 1-celled and 1-seeded.

Polygonaceae. - Herbs. Stipules sheathing the stem & the nodes.................................... 183

Urticace.e. - Herbs. Stigma 1. Flowers monoecious or dioecious, in spikes or racemes. No chaff-like bracts among the flowers. Or, Stigmas 2; leaves pal-mately-compound............................. 198

Illecebraceae. - Herbs, small, tufted. Flowers greenish or whitish, terminal. Stamens as many as the divisions of the 5-parted calyx and opposite them, or fewer, perigynous. Sepals hooded at the top and bristle-pointed. Style 2-cleft............. 183

Amarantacae:. - Herbs. Flowers greenish or reddish, in spikea,with chaff-like bracts interspersed. Stigmas 2. 187

Chenopodiacee. - Herbs. Flowers greenish, in spikes.