722 



HALORAGACEyE. 



[Epigynous Exoge>>. 



an 



Order CCLXXVII. HALORAGACE^.— Hippurids. 



Ilalorageae, R. Brown in Flinders, 17. (1814) ; DC. Prodr. 3. 65 ; Bartl. Ord. Nat. 314. j Endl. Gen. 

 cclxvi. ; Wight lllustr. 2. 23. — Hygrobiese, Rich. Anal. Fr. (1808). — Ilippurideae, Link. Enum.l. 

 5. (1821).— Cercodiana?, Just. I><e~t. ^V. Nat (1817). — Hydrocaryes, Link Enum. Hort. Ber. 1. 14!. 

 (1821).— Onagrari.-p, § Hydrocaryes, DC. Prodr. 3. 63. 11828). 



Diagnosis.— Myrtal Exoycns, with a plurilondar ovary, polypetalov* or apetalous flowers, 

 ■ open minute calyx, definite stamens, pendulous ovules, and minute cotyledons. 



Herbaceous plants or uuder-shrubs, often growing in wet places. Leaves cither 

 alternate, opposite, or whorled. Flowers axillary, small, either in terminal panicles or 



( sessile, occasionally 



ti WlD'^^ ■ monoecious or dioe- 



LlJ ij/J ■i^s^Jrs^'X j\ g^ cious by abortion. 



Calyx adherent, with 

 a minute limb, which 

 is 2- 4 -toothed, or 

 perfectly undivided. 

 Petals inserted into 

 the summit of the 

 calyx, or 0. Stamens 

 inserted in the same 

 place, equal in num- 

 ber to the petals, or 

 occasionally fewer. 

 Ovary adhering inse- 

 parably to the calyx, 

 with 1 or more cells ; 

 style none ; stigmas 

 Y> equal in number to 

 the cells, papulose, 

 or pencil-formed ; 

 ovules pendulous, 

 anatropal. Fruit dry, 

 ndehiscent, mem- 

 branous, or bony, 

 with 1 or more cells. 

 Seeds solitary, pen- 

 dulous ; albumen 

 fleshy or ; embryo 

 straight ; radicle su- 

 perior, large ; coty- 

 ledons much smaller. 

 These plants may 

 be regarded either 

 as a distinct Order, 

 or as a mere degene- 

 ration or imperfect 

 ft >rm of Onagrads, 

 from which their mi- 

 nute calyx and soli- 

 tary pendulous seeds 

 distinguish them ; to 



which may be added an evident tendency on the part of Hippurids to lose their petals 

 altogether. In Hippuris itself the flower is in the simplest possible form ; for it is re- 

 duced to a calyx of the smallest size, it has no petals, but one stamen and but one carpel. 

 It therefore furnishes an instance of the approach of Myrtals to the Asteral Alliance. 

 This reduction of the fruit to one carpel only, seems however to lie very different in Hip- 

 puris from that of Fringe-myrtles : for the latter have a multiplication and excessive deve- 

 lopment of every other organ, to which the pistil forms the exception ; but in Hippuris 



Fig. CCCCLXXXII.— Loudonia aurea. 1. a complete flower: 2. a section of the ovary. 



Fig. CCCCLXXXII. 



