270 SYSTEMATIC BOTANY. 



are very hy groin etric, the valves opening when wet and closing when dry. 

 It is a rather large Order, of which the majority belong to the sandy tracts 

 of the Cape, but a few are found in South Europe, America, China, and the 

 South Seas. The foliage of M. edule (Hottentots' fig) is eaten at the 

 Cape ; M. emarcidwn acquires narcotic properties when fermented. 

 Several are burnt for the soda-ash in Egypt, Spain, &c. The seeds of 

 some yield a kind of flour. 



PAPAYACE^E are trees or shrubs, sometimes with an acrid milky 

 juice, alternate, lobed, long-stalked leaves, and diclinous, sometimes herma- 

 phrodite, dichlamydeous flowers. Male fl. : calyx free, minute, with 

 o teeth j corolla sympetalous, with 5 lobes ; stamens definite, epipetalous. 

 Female fl. : Petals 5 ; corona filamentous or fimbriate, sometimes none ; 

 ovary free, 1-celled, with 3-5 many-seeded parietal placentas ; fruit suc- 

 culent or dehiscent j embryo in the axis of fleshy perisperm. Illustrative 

 Geneva : Carica, L. ; Modecca, L. ; Ceratosicyos, Nees. The present Order 

 stands near to Cucurbitacese and to Passifloraceae, differing, however, in 

 important respects from both, since the former have an inferior ovary 

 and aperispermic seeds ; the latter, hermaphrodite flowers and a charac- 

 teristic coronet arising from the tube of the flower, of a different nature 

 to the staminodes or sterile stamens of the present group. Bentham and 

 Hooker include it under Passifloraceee. The Papaw-tree, Carica Papaya, 

 has a succulent fruit, edible when cooked, but the juice of the unripe fruit 

 and the seeds appear to be very acrid. C. digitata (Brazil) is regarded 

 as a deadly poison, and its juice blisters the skin. The species of 

 Carica are natives of South America, the other genera are East-Indian or 

 African. 



PANGIACEJE are an Order of arborescent plants closely related to 

 Papayaceae, differing chiefly in being polypetalous, and by the female 

 flowers having scales in the throat; the number of parts in the floral 

 circles also appears more variable. They constitute a Tribe of Bixaceae 

 in the ' Genera Plantarum ' of Bentham and Hooker. They are poisonous 

 plants found in the hotter parts of India. Hydnocarpus venenatus is a 

 native of Ceylon ; its fruit produces dangerous intoxication. The seeds 

 of Pangium are sometimes used, after boiling and extraction with water, 

 as a spice, but even then have cathartic properties. Genera : Pangium, 

 Reinw. j Gymnocarpea, K. Br. ; Hydnocarptis, Gaertn. 



PASSIELOEACE^E. PASSION-FLOWERS. 

 Coh. Passiflorales, Benth. et Hook. 



Diagnosis. Climbing plants, rarely erect trees, with tendrils andfoliace- 

 ous stipules ; leaves and leaf-stalks often glandular ; flowers perfect ; calyx 

 5-parted, with numerous filamentous processes springing from the tube 

 of the flower (receptacle), inside the 5 petals; stamens 5, monadelphous, 

 adherent to the stalk of the 1-celled ovary, which latter is free from the 

 calyx, and has 3 or 4 parietal placentas and as many clavate styles ; fruit 

 mostly succulent, stalked; seeds numerous, aril late: embryo straight, 

 iu thin fleshy perisperm. Illustrative Genera : timeathmannia, Soland. ; 

 Passiflora, Juss. j Tetrapathcea, DC. ; Dilkea, Mast. 



Affinities, &c. This Order is generally associated with the Cucurbita- 



