PODOSTEMIACEJE. 334 PODOSTEMOM. 



Stem floating or prostrate, 8—16 inches long, filiform, with numerous whorls 

 of leaves. These are dichotomously divided into 2 or more filiform segments. 

 Flowers minute, axillary, sessile, with sessile anthers. Fiuit an oblong, 

 beaked capsule, with 1 seed. July— Sept. Hornicurt. 



ORDER CXXl. CALLITRICACE^. 



FIs. — Mostly moncEcious, achlamycleous, with an involucre of 2 bracts. 

 ,S7a.—l (rarely 2). i?'(7a??ien< slender. j4n!/i. 1-celled, 2-valved. 

 Ova. — 4-cellert, 4-lobed. Styles 2. Stigmas simple points, 

 i^r.— 4-celIecl, 4-seeded, indehiscent. Seeds peltate, albuminous. 



An order consisting of a single genus, Callitriche, which is both European and Ameri- 

 can. Small, aquatic herbs, with opposite, simple, entire leaves. Flowers axillary, 

 solitary, very minute. 



C ALLITRI'CHE. 

 Character the same as that of the order. 



Gr. K.a.'koi, beautiful, &gi|, Tgix;o«, hair; alluding to the numerous, slender 

 stems or leaves. Root annual. 



C. VERNA. Muh. C. intermedia. Willd. C. aquatica. Bic. 



Floating ; upper leaves oblong-spathulate, lower ones linear, obtuse or emar- 

 ginate; capsule with the lobes obtusely margined. This little polymorphous 

 plant is common in shallow streams and muddy ])Iaces. Stem floating, 1 — 2 

 feet long, composed of 2 tubes, simple or branched. Leaves 2 at each node, 

 becoming crowded above into a starlike tuft upon the surface of the water, 

 the lower ones becoming gradually narrower, and the lowest quite linear. 

 Flowers wliite, axillary, 1 or 2 together, often monoecious. Anther a little 

 exserted, yellow. May — Sept. ll'ater SUnwort. 



p. autuinnnUs. (Dar!. C. autumnalis, L. C. linearis. P.) ; floating; haves 

 nearly all linear, I-nerved, truncate or emarginate, the upper ones a little 

 dilated towards the end. In similar situations with, and generally accom- 

 panying the former. 



y'. tcrrestris. {Darl. C. terrestris. Raf. C. brevifolia. P.) ; procumbent and 

 dift'use ; le.ives all oblong, obtuse, crowded, fleshy. Grows on soft mud, 

 overspreading the surface. This form evidently depends on the locality. 



ORDER CXXII. PODOSTEMIACE.^. 



f /^,._Mono5cious, achlamydeous, bursting through an irregularly lacerated spathe. 

 Sta.— Ollen reduced to 1 or 2, and monadelphous. 

 Ora.— Free, 2— :3-celled. Styles 2 or 0. Stigmas 2—3. 

 fr.— Capsule subpedicellate, opening by 2 valves. 

 ,5(/j(._Xumi.rous, without albumen, aUached to a central column. 



A small order of aquatic, moss-like herbs. Flowers inconspicuous. They are natives 

 of America and Asia. 



PODOSTE'MUM. 

 Stamens 2, with the tilamenls united below; ovary oblong- 

 ovoid ; stigmas 2, sessile, recurved ; capsule 2-ce!led 5 seeds 

 minute. 



Gr. (Trovi) -TTohoi. a foot, a-Trif^ov, a stamen ; in allusion to the stamens 

 being supported apparently on a common footstalk. Small, submersed 

 aquatics, adhering to rocks and pebbles. Leaves alternate, dissected. 



