LINN^JAN CLASS XVIII., XIX. 187 



CLASS XVIIL— GYNANDRIA. 

 Orders I. and II— MONANDRIA and DIANDRIA. 



The genera of these orders form the Natural Order Orchidacece, No. 

 122. 



Order V.— PENTANDRIA. 



Asclepias. Sepals small, 5-parted. Corolla 5-parted, reflexed. Sta- 

 minal crown 5-leaved, each with a subulated, averte process. Pollen 

 in 10 masses, arranged in pairs. Follicles 2. Seeds comose. Asclepi- 

 adacece, 79. 



Gonofobus. Calyx small. Corolla rotate, 5-parted. Staminal crown 

 shield-form, lobed. Pollen masses in 5 pairs. Follicles 2. Asclepiada- 

 cecc, 79. 



Apocynum. Calyx persistent, 5-cleft. Corolla 5-lobed, regular. 

 ./Estivation twisted. Stamens 5. Anthers sagittate. Follicles long, 

 linear. Apocynacece, 80. 



Amsonia. Calyx 5-parted. Corolla funnel-shaped, with the throat 

 closed. Follicles 2, erect. Seed terete. Apocynacece, 80. 



Ec/iites. Calyx 5-parted, with acute segments. Corolla funnel- 

 shnped. Throat miked. Anthers adhering to the stigma. Follicles 2, 

 long, slender. Apocynacece, 80. 



Orders VI. and X.— I1EXAXDRIA and DECANDRIA. 

 These genera form the Natural Order Aristolochia, No. 106. 



CLASS XIX.— MONCECIA. 

 Order I— MONANDRIA. 



Zontcra. Perianth none. Stamens and pistils separated in two rows 

 upon one side of the spadix. Drupe 1 -seeded. Naiadacece, 139. 



Cauliva. Nojas. Perianth none. Anther 1, sessile. Style filiform. 

 Stigma 2 cleft. Capsule 1-seeded. Naladaccce, 139. 



Euphorbia. Involucre campanulate, 5 — 10-toothed. the inner seg- 

 ments erect. Stamens attached to the inside of the involucre. Fila- 

 ments articulated. Pistil central. Fruit stiped, 3-angled, 3-celled. 

 Euphorbiacece, 108. 



Order II. 



Podoatemum. Flowers naked, bursting through an irregularly laeer 

 ated spa the. Stamens monadtlphous. Ovary 2-celled, capsular. 

 Seeds numerous. Podostemacecc, 112. 



Lemna. Spirodela. Sterile and fertile flowers collateral. Perianth 

 1-leaved. Stigma funnel-form. Capsule 1-celled, 1 — 5-seeded. Ara> 

 cece, 138. 



Order III— TRIANDRIA. 



Typha. Flowers collected into a long, dense, cylindric spike. Sta- 

 minate florets above. Pistillate florets below, on the same axis. Fruit 

 very small, oblong, stipitate. Aracex, 138. 



Sparganum. Flowers in dense, spherical heads, the sterile ones 

 above. Perianth 3-leaved. Fruit dry, 1-seeded. Aracect, 138. 



