344 PATAGONIAN EXPEDITIONS : BOTANY. 



Ph. and Q. linarioides Ph., but distinguished by its free crustaceous calyx 

 enclosing the fruit. 



Family 29. OLACACE.E. 



Trees or shrubs with mostly alternate, simple, entire exstipulate leaves, 

 and perfect, regular, 4-6-merous flowers, having a double perianth, the 

 outer being small, cup-like, adnate to the hypogynous disk. Inner peri- 

 anth-leaves distinct or united, and bearing 1-3 (mostly 2) times as many 

 stamens. Ovary i -celled, rarely partially 2-4-celled ; the cells mostly 

 with i pendulous ovule. Fruit a i -seeded drupe or nut, with large 

 endosperm and no testa. 



Species 140, tropical. Two genera occur only in S. Amer. and W. 

 Afr., one, Heisteria, with 20 sp. in S. Amer. and i sp. in Afr., the other 

 Ptychopetalum, with 2 sp. in W. Afr. and i in Guiana and N. Brazil. It 

 is uncertain whether the outer floral cup is a true calyx, or an involucre. 



XIMENIA Plum. 



Flowers 4-merous ; inner perianth of 4 (rarely 5) linear, white leaves, 

 hairy inside, apically revolute. Stamens 8-10. Ovary long-conical, 4- 

 celled, 4-ovuled. Drupe ovoid, globular. Often with thorny branches. 



Species 5, in S. Amer., Africa, Asia, and N. Caledon. Its hard wood 

 is used as sandal-wood in the East Indies, and its fruit is eaten. 



X. AMERICANA Linn. 



Leaves oblong. Peduncles several-flowered, the lower often changed 

 into spines. 



(Guiana, Brazil, etc.) (Fig. in Eng. and Prantl, iii, i, p. 237.) N. 

 Patagon. 



Family 30. HYDNORACE.E. 



Succulent, parasitical herbs, with branching, leafless creeping rhizoids, 

 which radiate from the insertion of the nutritive root, and produce here 

 and there large flowers emerging from the ground. Flowers hermaphro- 

 dite, with single, 3-4-lobed, regular perianth, and inferior ovary. Stamens 

 sessile within the tubes, isomerous and alternating, with many anthers 

 having linear pollen sacs. Ovary i -celled, with many parietal placentce, 



