254 



embryo on the outside of the albumen, and at the end most remote from the hilum.— Herbal 

 ceous plants with fibrous roots. Leaves radical, ensiform, with dilated equitant ecarious bases. 

 Flowers in terminal, naked, imbricated heads. 



Affinities. United with Restiaceae by Mr. Brown and others, separated 

 as a distinct order by Agardh and Desvaux, this appears to me to be essentially 

 distinguished by the higher development of its floral envelopes, a character 

 which I cannot but regard as more important than the mere accordance in the 

 structure of the seed, in consequence of which chiefly it has been retained in 

 Restiaceae. Those who have distinguished this order have referred to it seve- 

 ral genera which by no means enter into the idea I have of the limits that 

 should be prescribed to it, particularly Aphyllanthes, which is surely a Juncea. 

 Mr. Brown remarks, that the anomalous genus Philydrum, and even Burman- 

 nia, are related to Xyris ; and that these plants agree in some respects with 

 Orchideae in the structure of the seed and stamen (Prodr. 264). To me it 

 seems that the relation of Xyrideae is very great with Commelineae. 



Geography. All natives of the hotter parts of the world, chiefly in the 

 tropics of America, Asia, and Africa. Two or three species of Xyris are found 

 in the southern states of North America. 



Properties. The leaves and root of Xyris indica are employed against 

 itch and leprosy. Jlgardh. 



Examples. Xyris, Abolboda. 



CCXXXIV. BROMELIACEAE. The Pine-Apple Tribe. 



BrOmeli^:, Juss. Gen. 49. (1789); Diet. Sc. Nat. 5. 347. (1817).— Bromeliaceje, LA.ndl.in Bot. 

 Reg.foL 1068. (1827); Dec. and Duby, 412. (1828.) 



Diagnosis. Tripe taloideous hexandrous monocotyledons, with an inferior 

 ovarium, and an albuminous embryo. 



Anomalies. Some, as Tillandsia, have a superior ovarium. 



Essential Character. — Calyx 3-parted or tubular, persistent, more or less cohering - with 

 the ovarium. Petals 3, coloured, withering- or deciduous, equal or unequal. Stamens 6, in- 

 serted into the base of the calyx and corolla. Ovarium 3-celled, many-seeded ; style single ; 

 stigma 3-lobed, often twisted. Fruit capsular or succulent, 3-celled, many-seeded. Seeds nu- 

 merous ; embryo taper, recurved, lying - in the base of mealy albumen. — Stemless or short-stem- 

 med plants, with rigid channelled leaves, often covered with cuticular scales, and spiny at the 

 edge or point. Fruit sometimes eatable. 



Affinities. Stratiotes among Hydrocharideae has so much the foliage of 

 this order as to render it probable, taking the fructification also into account, 

 that the nearest affinity of the Pine-Apple tribe is with the former. It is dis- 

 tinguished from other tripetaloideous orders, when its ovarium is inferior, by its 

 albuminous seeds and hexandrous flowers, while, in those cases in which the 

 ovarium is superior, it is recognised by its polyspermous trilocular fruit ; Com- 

 melineae and Xyrideae, with which alone it can be confounded, differing in this 

 respect. The habit of Bromeliaceae is peculiar; they are hard dry-leaved plants, 

 generally with a mealy surface, and having a calyx the rigidity of which is 

 strongly contrasted with the delicate texture of the petals. The habit of 

 Agave is that of Aloe in Asphodeleae, to which Bromeliaceae approach ; it was 

 probably this consideration which induced M. Desfontaines to place Pitcairnia 

 with the latter order. 



Geography. All, without exception, natives of the continent or islands of 

 America, whence they have migrated eastward in such numbers, as to have 



