256 



with the embryo on the outside of the albumen, and at the end most remote from the 

 hilum — Herbaceous plants with fibrous roots. Leaves radical, ensifomi, with dilated equi- 

 tant scarious bases. Flowers in terminal, naked, imbricated heads. 



Affinities. United with Restiaceae by Mr. Brown and others, sepa- 

 rated 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 several 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 Burmannia, are related to Xyris ; and that these plants 

 agree in some respects with Orohideoe in the structure of the seed and stamen 

 (Prodr. 264). To me it seems that the relation of Xyridese is very great 

 with Commelineae. 



GEOGRAniY. 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. Agardh. 



Examples. Xyris, Abolboda. 



CCXXXIV. BROMELIACE^. The Pine-Apple Tri«e. 



Bromeli^, Juss. Gen. 49. (1789); Diet. Sc. Nat. 5. .347. (1817) BuomeliacEjE, 



Lindl. in Bot. Reg. fol. 1068. (1827); Dec. and Dubtj, 472. (1828.) 



Diagnosis. Tripetaloideous hexandrous monocotyledons, with an infe- 

 rior 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 G, inserted into the base of the calyx and corolla. Ovarium 3-celled, niany- 

 seeded ; style single ; sliyma H-lobed, often twisted. Fruit cajjsular or succulent, ;{-celle(J, 

 many-seeded. Seeds numerous ; embryo taper, recurved, lying in the base of mealy ali)u- 

 men — Stemless or short-stemmed ^plants, with rigid channelled leaves, oi'teii 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 distinguished 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 

 Irilocular fruit ; Commelinea) and Xyrideu', with which alone it can be con- 

 founded, diftcring in this respect. The habit of Bromeliaceoc is peculiar; 

 they are hard dry-leaved plants, generally with a mealy surface, and hav- 

 ing a calyx the rigidity of which is !^t^ongly contrasted with the delicate 

 texture of the petals. The habit of Agave is that of Aloe in Asphodelecc, 

 to which Bromeliaceai approach : it was probably this consideration which 

 induced M. Desfontaincs 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 



