3tf NATURAL HISTORY OF PLANTS. 



ment, and an anther with two sublateral cells independent of each 

 other towards the two extremities, and dehiscing towards the edges 

 or a little outwards by two longitudinal clefts. The gynrcceum is 



inserted at the bottom of the receptacle, in the 

 Petiveria aiiiacea. concav ity of which it is partly lodged ; it is com- 

 posed of a unilocular ovary, the short eccentric 

 style having a tendency to become gynobasic, and 

 being crowned by a stigmatiferous penicillate apex. 

 In the interior is a single ovule, subbasilar, erect 

 " and amphitropous, with the micropyle turned 



downwards and from the side of the back of the 

 carpel. 1 The fruit is an unsymmetrical achene, narrow and elongated, 

 accompanied at its base by the erect perianth and the persistent fila- 

 ments of the stamens, while on the side are found the remnants of the 

 style. 2 It is surmounted by from four to six prickles inserted in its 

 upper part, and which existed upon the ovary where they were ascen- 

 dent, while here they are, in hardening, reflexed upon the pericarp. The 

 seed is suberect, narrow, folded upon itself towards the middle of its 

 length in the same way as the embryo, 3 whose cotyledons have their 

 apex turned back towards the radicle, which is inferior. These 

 cotyledons are very unequal ; that which touches the radicle being 

 longer and narrower and having reflexed edges, while the other, by 

 which it is enveloped, and whose edges are in flexed, is much thicker 

 and shorter. A little mass of albumen accompanies the embryo, placed 

 towards the edges and in the intervals of the two folded parts. The 

 Petiverias are undershrubs of tropical America. There are two or 

 three species 4 of them. All their parts have an alliaceous odour. 

 Their leaves are alternate, simple, entire, petiolate, accompanied by 

 two small lateral stipules. Their flowers are in terminal or axillary 

 racemes, but which seem at first to be spikes, so short and thick are 

 their pedicels ; each is placed in the axil of a bract, and bears at a 

 variable height two sterile bractlets. 



1 It has two coats, and its eudostome of the fruit, which is found where the remain* of 

 forms a long opening which penetrates across the the style is seen. 



exostome to the outside, and presents a narrow 3 Described wrongly by Moquin (Prodr., xiii. 



aperture at its swollen apex. sect. ii. 4) as straight; it is folded upon itself more 



2 Its form is comparable to that of a grain of tightly still than that of other plants of the same 

 oats; it bears also on one side a longitudinal group. 



mesial groove, finished above by a slope; but 4 Gom., Obs„ (1803), 13. — Fiscn. et Met., 



this does not correspond to the organic apex Ind. Sem. Rort. Petrop. (1835), 35. 



