504 ORDER CXIII. CALLITRICHACE.E. 



Genus II.— MACLU'RIA. Nutt. 20—4. 

 (In honor of Wm. Maclure.) 



Flowers dioecious. Fertile flowers collected into a dense 

 head ; style 1, long, villous ; achenia obovate, compressed, im- 

 bedded in a pulp, all forming a fruit the size of an orange, with 

 an irregular surface. A small tree, with straggling branches. 



1. M. aurantia'cea, (Nutt.) A tree ; branches flexuous, terete. Leaves 

 alternate, entire, with supra-axillary spines. Flowers axillary. — ^ . In 

 the Southwest, on the banks of streams. Osage Orange. Bow-wood. 



Used in forming hedges, and promises to be the best plant for the Southern States. 

 It is attacked by no animal, and in a few years forms an impenetrable hedge. The 

 Fig, Ficus carica, belongs to this Order. Its fruit consists of a succulent hollow re- 

 ceptacle, inclosing numerous single-seeded carpels, forming a syconus. 



Order CXIL— PODOSTEMA'CE^E. 



Flowers naked, monoecious, bursting through an irregularly 

 lacerated spathe. Stamens hypogynous, monadelphous, 2 or 

 more, alternately sterile and shorter. Ovary 2-celled, with nu- 

 merous ovules. Stigmas 2 — 3. Fruit capsular. Seed nu- 

 merous, minute. Flowers minute. Aquatic plants, with capil- 

 lary leaves. 



Genus L— PODOSTE'MUM. Rich, 19—2. 

 (From the Greek pous, foot, and stemon, a stamen, from their standing on a foot) 



Genus the same as the Order. 



1. P. ceratophyl'lum, (Mich.) Stem floating, filiform, stiff, horn-like. 

 Leaves alternate, pinnate, many-cleft. Flowers axillary, solitary. Sta- 

 mens 2, afiixed to a common pedicel. Stig7nas 2, sessile. Capsule ovate, 

 2-valved, 2-celled, many-seeded. — If. July. In the beds of rivers. 



River-ioeed, 



Order CXIIL— CALLITRICHA'CEJS. 



Flowers perfect or imperfect, with 2 opposite colored bracts. 

 Stamen 1. Anthers reniform, 1 -celled. Ovary solitary, 4- 

 cornered, 4-celled. Ovules solitary. Styles 2, subulate. Stig- 

 mas simple points. Fruit indehiscent, 4-celled, 4-seeded. Seed 

 peltate. Flowers axillary, solitary, very minute. Small aqua- 

 tic, herbaceous plants. 



Genus I.— CALLIT'RICHE. L. 1—2. 



(From the Greek kallos, beauty, and trix, hair 



Genus the same as the Order. 



1. 0. heterophyl'la, (I'ursh.) Stem floating, creeping, round. Float- 

 ing leaves spatulate, immersed ones Linear, all opposite, sessile, entire. 

 Perianth persistent, lanceolate, white. Filament subulate. Styles 2, 

 subulate. — %. Mav — June. Still waters. 



