282 



APETALOTTS OEDERS. 



Sl-T. Calliteichace^, the Water-Starwort Tribe. — Small 

 aquatic hei'ls. Leaves opposite, entire. Flowers axillar}^, naked, 

 with a 2-leaved involucre. Stamen single, with a slender fila- 

 ment. Ovary 4-celled, 4-seeded, indehiscent in fruit. Seeds 

 albuminous ; embryo inverted. 



Genus. — Callitriclie. 



518. PoDOSTEMACE^, tlw River-weecl Tribe. — Aquatic herbs 

 with the habit of liverworts or mosses. Lea/oes capillary, 

 linear, or irregularly lacerated ; or minute and densely imbri- 

 cated. Flowers small, arising from a kind of spatha. Stamens 

 definite or indefinite, distinct or monadelphous. Ovary 2-3- 

 celled ; ovules numerous, attached to a fleshy central placenta. 

 Fruit a ribbed capsule. Seeds numerous, minute, exalbumi- 

 nous. 



Gents. — Podostemum. 



519. EuPHORBiACEJE, the Spurge Tribe. — Trees^ shrubs^ or 

 herl)S.^ often with a milky juice. Leaves simple, opposite or al- 

 ternate. Floioers monoecious or dicecious^ axillary or terminal, 

 sometimes inclosed in an involucre. Calyx inferior, lobed, or 

 w^anting. Corolla consisting of petals or scales equal in num- 

 ber to the divisions of the calyx, or pj^ 204. 

 wanting. Omcry free, 1, 2, 3, or more 

 celled. Fruit mostly capsular, the ele- 

 mentary carpels or cocci separating 

 from their common axis. Seed sus- 

 pended ; embryo inclosed in fleshy al- 

 bumen. 



a. Properties : acrid and poisonous. 



Genera.— Euphorbia, Stillingia, Tragia, Acaly- 

 plia, Jatropha, Ricinus, Croton, Buxus, Pachy- 

 sandra, Phyllanthus, 



Fig. 204, Euphorbia corollata (spurge ipecacu- 

 anha). Root very long, yellowish ; stem simple, 

 erect ; leaves oblong, obtuse, crowded ; fioioers in 

 a large terminal umbel, rays fii'st trifid, then di- 

 chotomous. 



520. Empretace^, the Crowberry Tribe. — Low shrubs. Leaves 

 opposite, or somewhat verticillate, evergreen. Flowen^ dioe- 

 cious or polygamous, in the axils of the uppermost leaves. 

 Perianth consisting of persistent, imbricated scales, the inner- 

 most often petaloid. Stamens 2-3, equal in number to the 

 scales in each row, alternate with the inner. Ovary 3-9-celled ; 

 ovules solitary, ascending. Fruit a drupe, with 3-9 bony nu- 

 cules. Seeds albuminous. 



Genera. — Empetrum, Ceratiola. 



621. JuGLANDAGEiE, the WaUut Tribe.— Trees. Leaves alter- 



