480 



ELATINACE^. 



[Hypogvnous Exogens. 



Order CLXXXI. ELATINACE^.— Water-Peppers. 



Elatineae, Cambessddes in Mdm. Mus. 18. 225. (1829) ; Aug. de St. H. Fl. Bras. 2. 159. (1830) ; Fl. Seneg. 

 1.42. (1832); Fischer and Meyer in Linncea, x. 69.11835); Wight lUustr. 1. t. 25; Endl. Gen. 

 ccxix. ; Meisner Gen. p. 131; Fenzl Darstellung, Sjc., p. 30. 



Diagnosis. — Rutal Exogens, with a many-seeded fruit which is finally apocarpous, and 



polypetalous flowers. 

 Little annuals, growing in marshy places, with fistular rooting stems. Leaves oppo- 

 site, with stipules between the petioles. Sepals 3-5, imbricated, distinct, or slightly con- 

 nate at the base. Petals of the same num- 

 ber as the sepals, imbricated, hypogjTious. 

 Stamens hypogynous, usually twice as 

 numerous as the petals. Ovary with from 

 3 to 5 cells, an equal number of styles, and 

 capitate stigmas ; o\'ules 00, anatropal. 

 Fruit capsular, 3-5-celled, opening at the 

 sutm'es, crowned by the styles ; the valves 

 either flat at the edge, or rolled inwards 

 and alternating with the angles of a central 

 placenta. Seeds 00, without albumen, 

 wrinkled transversely, cylmdrical, with a 

 straight embryo, whose radicle is turned 

 to the hilum, which is at one end of the 

 seed. 



This little Order was estabUshed by Cam- 

 bess^des, who distinguished it from Alsin- 

 aceae, with which a part had been con- 

 founded, by its capitate stigmas, the 

 dehiscence of its fruit, the small quantity 

 of albumen, and the straight, not curved, 

 embryo. It does not, however, appear 

 that the Water-peppers have any imme- 

 diate relation to the Silenal Alhance, of 

 which Alsinacese fonn a part. On the contrary, the species agree much better with 

 Tutsans (Hypericacese) even in the presence in the leaves of receptacles of resinous 

 secretions ; but they differ in having a persistent central axis in the fruit, and definite 

 stamens, on which latter account they fall into the ranks of the Rutal rather than the 

 Guttiferal Alliance. This view of their affinity seems confirmed by the curious genus 

 TetradicUs, a Syrian plant, with the habit of a Tillsea, on which account it has been even 

 referred to the Order of Houseleeks by Bunge {Linncea, xiv. 177). It is remarkable 

 for having in each cell of its fruit two seeds enveloped in the laminated sides of the dis- 

 sepiments, which sides adliere to the seeds, and seem as if they were really a part of 

 them ; the other seeds, however, are naked, and he in the space between the lateral 

 seeds. If it were not for this singular breaking up of the tissue of the dissepiments, 

 Elatine would be very near Tetradiclis. Now, there can be no doubt of the latter genus 

 being a member of the Rutal Alhance ; but its numerous seeds attached to two arm-like 

 free placentae forbid its being stationed in Rueworts, whither Mr. Fenzl has referi'ed it 

 {lAnnaa, xv. 295), or in Bean Capers, among which I had assigned it a doubtful place 

 in the Botany (still unpubhshed) of Col. Chesney's Expedition to the Euphrates. It 

 falls, however, well into the Order of Water-peppers, and contributes to confirm the 

 importance of that httle Order. 



Found in marshes in the fom' quarters of the globe. The Elatines are natives of 

 Europe and Asia, Bergias of the Cape of Good Hope and the East Indies, Merimea of 

 South America, and TetradicHs of the Syrian region. 



Dr. Wight says that in India the httle Bergia ammannioides bears the Tamool name 

 of Neer-mel-neripoo, or Water-fire, which seems a cmnous coincidence with the word 

 Water-pepper, given in EngHsh to Elatine, and seems to indicate a popular belief in 

 these plants possessing some acridity. 



Fig. CCCXXXII.— Elatine hydropiper. 

 placenta ; 4. and 5. seeds. 



^^^^ 



Fig. CCCXXXII. 



-Bowerhy. 1. a flower ; 2. a capsule after splitting ; 3. the 



