10 



NATURAL HISTORY OF PLANTS. 



Centraden ia Jlorihunda. 



and a variable foliage, sometimes that of Chcetostoma, sometimes 

 that nearly of Microlicia, In those called Pijramia the ovary has 

 four or five cells, and the hairs with which the various parts are 

 covered are starred. 



Lithohium, Castratclla, and Eriocnema, with the floral organization 

 of the preceding types, are herbaceous 

 plants, all from tropical America. A com- 

 mon shaft bears at its summit flowers soli- 

 tary or more generally collected in umbelli- 

 form few-flowered cymes. In the former 

 case the flower is trimerous, with six sta- 

 mens, anthers shortly claviform, emarginate, 

 with connective a little prolonged at the 

 base and destitute of appendage. In Castra- 

 tella the tetramerous flower has eight stamens 

 equally claviform, rounded and enlarged at 

 the summit, with two scarcely marked pro- 

 minences near the contracted base. The 

 ovary is half adherent ; it is free in Erioc- 

 nema, which has 4, 5-merous flowers with 

 pointed petals and twice as many stamens 

 with narrow elongate anther surmounting an 

 inflexed filament. 



In their habit the latter genera closely 

 resemble Bertolonia (fig. 14-16), one tribe 

 of which has received the name {Bertoloniece). The receptacle, in 

 the form of a reversed cone, more or less accrescent around the 

 fruit, is often furnished externally with angular prominences or 

 wings (in number 3-9). The calyx is short, formed of five sepals 

 with which alternate as many obtuse contorted petals. There are 

 ten stamens with undulated anthers without appendage ; and the 

 ovary, adherent to a variable extent, has three cells surmounted by 

 an equal number of superposed scales, forming an epigynous cupule. 

 The flowers are grouped, at the end of a common shaft, in a scorpioid 

 cyme, often much elongated. From Bertolonia we do not separate 

 generically Salpinga, having 4, 5-merous flowers and a spur-like 

 prominence below and behind the connective ; Macrocentum, whose 

 sepals, five in number, are dentelate instead of entire at margin; 

 Diplarpea, covered with coarse hairs and having five dentiform 



Fi:?. 13. Stamens. 



