XAi 



XATURAL niSTORY OF PLANTS. 



reeeptacli' like :i very Hat cup with a circular rim, and the bottom 

 pushed up in the middle like that of a wine-bottle. On this central 

 projection, the true ori,^^nic apex of the receptacle, are borne the 

 carpels, while the perianth and androceum are inserted on the edges. 

 The calvx consists of five sepals, valvate and slightly reduplicate in 

 the bud, or rarely a little imbricated. Outside the calyx are five 

 leaves alternating with the sepals, and forming what is called the 

 calycle.' The petals, alternate with the sepals, are shortly unguicu- 

 late, imbricated in the bud. The stamens are usually twenty in 

 numl)er. and are in this case arranged in three whorls ; there are five, 

 each in front of the median line of a sepal, then as many in front 

 of the petals, and lastly, ten others, one on either side of each of the 

 latter.'- Each consists of a free filament and an introrse or sublateral 

 two-celled anther, dehiscing longitudinally.^ A glandular disk, more 

 or less marked, lines the inside of the receptacle from the insertion of 

 the stamens to the central prominence, which is covered by the in- 

 definite carpels. These last are free, each consisting of a one-celled 

 ovary, surmounted by a style which is inserted at a variable height on 

 the ventral angle of the ovar}^, and gradually widens out towards its 

 truncate stigmatiferous summit. Inside the ovary, about half-way 

 up the ventral angle,* is inserted a descending subanatropous ovule, 

 whose micropyle looks upwards and outwards^ (fig. 418). The fruit 

 is multiple, composed of a large number of achenes," borne on the 

 prominent part of the receptacle, now much thickened/ fleshy, and 

 succulent.*' The calyx and involucre persist at the base of this 



' TLese are of stipular nature, each being 

 formed Ly the fusion of two adjaceut stipules. 

 I ndced, very frequently this fusion does not take 

 place, and the calycle consists of ten leaves, in 

 free or coherinfr pairs alternate with the sepals 

 (see Patkr, El<^m. de Bot., 90. figs. 143, 144). 

 In one yellow-flowered species, F. indica DC. 

 {Prodr., ii. 571), which Smith {Trans. Linn. 

 Soc, X. 372 ; — Walp., Ann., iv. 663) proposed 

 to make the ty])e of a distinct section under the 

 name of Duchesnea, the leaves of the calycle 

 are broad and with incised edges, and are far 

 larger than the sejials themselves. 



^ When there are more than twenty stamens 

 it is due to the occurrence of more or less nume- 

 rous deduplications, so that in several whorls 

 two or three of these organs may occujiy the 

 place of a single one. 



•' The pollen is ellipsoidal with three longi- 

 tudinal grooves, which in water become as many 



bauds, sometimes smooth, sometimes papillose. 

 We meet with neai-ly the same organization in 

 nearly all the genera of this series — Potentilla, 

 Geum, Dri/as. 



* The insertion of the ovule is lower down 

 according as that of the style (the true organic 

 apex of the ovary) approaches the base. Thus, 

 in F. indica the style is attached at the junction 

 of the superior and middle thirds of the ovary ; 

 the ovule is here very distinctly descending, and 

 its anatropy is far more perfect than where the 

 style is inserted lower down. 



■'' The ovule has a single coat. 



^ More frequently they are true drupes ; but 

 the mesocarp is very thin. 



' Usually it rises up in the intervals between 

 the fruits, so that they are inserted in little pits. 

 But sometimes, as in F. indica, this insertion is 

 on slight prominences of the receptacle. 



* It may be harder and almost fibrous, of a 



