252 



plants; in the temperate zone, between 36° and 52° latitude, l-4th ; and 

 towards the polar circle, nearly l-3d. 



The most important substance that they produce is amylaceous matter, 

 which exists in great quantity in some of them, which hence become of 

 incalculable value as aliment for man : such are all the Corn tribe, Plantains, 

 and some Palms, which contain it in their fruit; the Sago and other Palms, 

 in which it occupies the trunk ; and the eatable Aroideous plants, Orchises, 

 Yams, &c., in which it is found in the root. Sugar, gluten, oil, and aromatic 

 principles, are also frequently met with in Monocotyledons ; but, as Hum- 

 boldt well remarks, acids, bitters, resins, camphor, tannin, milk, or poisonous 

 matter, are either wholly wanting or very uncommon. The latter chiefly 

 exists in Aroidese, some Amaryllidese, and Melanthacese. 



The orders of Monocotyledons are given in the state in which they now 

 exist; but it must be confessed that the characters and limits of many of 

 them are far from satisfactory. The whole of those which border upon 

 Asphodeleee require to be reconsidered by some botanist who is in possession 

 of the means of examining them in great detail ; their actual condition is, no 

 doubt, attributable to the partial view that has hitherto been taken of them. 

 Some one should do that for Asphodelese which the late M. Richard so 

 admirably executed for Alismacese and their affinities. 



Endogenous plants are conveniently divided into those in which the floral 

 envelopes are verticillate (Petaloidece), and those in which the flowers consist 

 of imbricated bractese (^Glumacece). 



TRIBE I. PETALOIDE^. 



These comprehend all Monocotyledons except Grasses and Sedges, They 

 are known by their flowers being fully and normally developed ; or, if there 

 is no proper floral envelope, by the sexual apparatus being in that case 

 naked, and not covered by imbricated bractese. Some of them have both 

 the calyx and corolla equally formed, and coloured so as to be undistinguish- 

 able, unless by the manner in which those parts originate : these constitute 

 the Hexapetaloideous form. Others have the calyx and corolla distinct, as 

 in Dicotyledons, to which, in fact, they nearly approach in Butomeae, which 

 have a strong analogy with Nymphaeaceee, and in Alismacete, which cannot 

 be considered widely apart from Ranunculaceae : these are named Tripe- 

 taloideous. Lastly, there is a group of orders in which the floral envelopes 

 have a manifest tendency to abortion, being always small, and of a herba- 

 ceous colour, if present ; often altogether wanting ; and frequently less than 

 6, the normal number of Monocotyledons : as many of them are arranged 

 in a spadix, and as most of them have a distinct tendency to that kind of 

 inflorescence, the form is called Spadiceorts. 



LIST OF THE ORDERS. 



