LINN^CAN CLASS IV. 169 



CLASS IV.— TETRANDRIA. 



Order I.— MONOGYNIA. 



A. Flowers superior. a. \-petaled. 



Cephalanthus. Flowers in a dense globose head. Calyx 4-toothedL 

 Corolla 4-toothed. Style exserted. (Button-bush.) Rubiacece, 66. 



Galium. Calyx teeth obsolete. Corolla rotate, 4-cleft. Styles 2. 

 Fruit twin-carpeled, each 1-seeded. (Bed-straw, cleavers.) Rubiacect, 

 66. 



Spermacoce. Calyx 4-leaved, or 4-parted. Corolla 4-parted. Cap- 

 sule 2-celled, with 1 seed in each cell. Rubiacece, 66. 



Diodia. Calyx 2-cleft. Corolla funnel-shaped, 4-cleft. Capsule 2 

 celled, 1 seed in each cell. (Button-weed.) Rubiacece, 66. 



HedyotU. Houdonia. Calyx 4-parted, persistent. Corolla 4-cleft, 

 shorter than the calyx. Capsule 2-celled, 2-valved, many-seeded. 

 (Venus' pride.) (Dwarf-pink.) (Bluets.) Rubiacece, 66. 



Milchella. Flowers in pairs. Calyx 4-toothed. Corolla 4-lobed, 

 funnel-form, bearded inside. Stigmas 4. Fruit a double drupe. 

 (Partridge-berry.) Rubiacece, 66. 



Polypremum. Calyx 4-parted, persistent. Corolla 4-cleft, rotate, 

 throat hairy, capsule compressed, many-seeded. Rubiacece, 82. 



Allionia. Involucre oblong, simple, 3 flowered. Perianth longer 

 than the involucre, irregular. Nyctaginacece, 98. 



Rubia. Calyx 4-toothed. Corolla 4 — 5-cleft, bell-form. Berries 2, 

 one-seeded. (Madder.) Rubiacece, 66. 



b. k-petaled. 



Cornus. Calyx 4-toothed, minute. Petals 4, distinct. Fruit a 

 drupe, berry-like. (Dog- wood.) Cornacece, 63. 



Ludwigia. Calyx 4-parted, united to the ovary. Ovary quadrangu- 

 lar, 4-celled, many-seeded. (False Loose-strife.) Onagracece, 50. 



B. Flowers inferior. a. l-petaled. 



Plantago. Calyx 4-cleft. Corolla 4-cleft. Pod 2-celled, 2-several- 

 seeded. (Rib-grass.) (Plantain.) Plantaginacece, 97. 



Centaurella. Burtonia. Calyx 4-parted, persistent, glabrous. Co- 

 rolla 4-cleft. Capsule 1 -celled, 2-valved, many-seeded. Gentianacece, 

 82. 



Sanguisorba. Calyx tubular, quadrangular. Limb 4-parted. Petals 

 none. Carpels 1 — 2. Fruit an achenium, included in the calyx (Her- 

 baceous.) Rosacece, 44. 



Frasera. Calyx 4-parted. Corolla 4-parted, segments with bearded 

 glands. Capsule oval, flattened, 1-celled, 2-valved, few-seeded. (Wild 

 Colombo.) Gentianacece, 82. 



Scopa*ia. Calyx 4 — 5-parted. Corolla rotate, 4-cleft, pilose in 

 the throat. Stamens 4. Anthers sub-sagittate. Seeds numerous, 

 angular, minutely reticulated. (Herbaceous.) Scrophulariacece, 90. 



LyMnm. Calyx 4-toothed, short. Corolla tubular. Stamens some- 

 times 5. Fruit 2-celled, many-seeded. (Matrimony.) Solanactat, 8ft. 



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