172 NATURAL UISTOBY OF PLANTS. 



all MaqnolUicca; are more or less so, But this character, practically 

 useful though it be, is certainly of no great importance in itself; 

 and it has ceased to be absolute since the Euptelea, which lack all 

 aroma, have been classed among MagnoUacea. Nor is the direction 

 of the ovule of fundamental value in separating the two orders, 

 because a descending ovule with the micropyle exterior, as in 

 M(u/no/in, answers really to an ascending ovule with the micropyle 

 interior, as seen in the uni or pauci-ovulate BUleniacea. But here 

 again, in practice, as we as yet know no Dilleniacece with definite and 

 suspended ovules, we may assert that the ovules of Magnoliacece, 

 solitary and few in number, have the micropyle always external, 

 whether they be descending, as in the true Magnolias and Scldzan- 

 clra, or ascending, as in lUic'mm. In Billeniacece with pauciovulate 

 carpels the micropyle, on the contrary, looks inwards. 



Moreover we must give up the attempt to distinguish Billeniacece 

 and MagiioliacecB by the presence or absence of stipules, since the 

 Schizandrece, llliciece, and Canellece have no stipules, while certain 

 IFonnias, Bavillas, &c., as we have said,' possess petiolar expansions 

 which behave exactly like the organs called stipules in Magnoliacece. 

 Nor is the symmetry of the flower sufficient to separate the two 

 orders absolutely ; for if it is true that the flower of Billeniacece is 

 often on a quinary type, it is equally true that that of Magnoliacece 

 is far from being constantl}" composed of trimerous verticils. The 

 Dillenias are almost Magnoliacece, as no one can fail to see on an 

 exact analysis of their flowers. The quinary symmetry of the 

 perianth, the verticillate arrangement of the carpels, the spiral 

 insertion of the androceum,- the stipuliforin dilatations of the petioles, 

 are facts which are all met with in one or other of the types of the 

 Magnoliacece? These too are very near the Calgcantliece. It is true that 

 as yet we have found none of the Magnoliacece with a receptacle 



' Seep. 120, and Adansonia, vi. 271. though much less evidently (see Adansonia, vii. 



^ As in the case of the Eanunculacea;, we shall be 361 ;" viii. 12). 



able to take into account the develoi)nient of the •'' We shall not here speak of the aril, which is 



flowers iu distinguishing MagnoliacecE from said to be highly developed in DilleniacecB and 



Dilleniaceft, as soon as the organogeny of the absent in MagnoliacecB, considering that the aril, 



former has been more completely studied. We as seen from tmr stand-point, is not of the same 



may now say that in all the MagnoliacecB we conformation in the two groups, but is really 



have as yet studied, the androceum is developed, more generalized in Magnolia than in Candollea, 



not centrifugally as in Dilleniacea, but iu a Mibberlia, &c., all the superficial cells of the 



spiral order and cenlripetally. This peculiarity former genus entering into its formation by their 



is very marked in Magnolia nn(\ Drimgs ; it also hypertrophy (see p. 132, note 7). 

 exists in lUicium anisaluni and parvlflorum, 



