APPENDIX. No. V. 439 



nearly related to them as Erythrospermum, well described and figured by the 

 same excellent botanist.* 



The increased number of stamina in Homalium, and particularly in the 

 genus from Congo, instead of presenting an objection to this affinity, appears 

 to me to confirm it. It may be observed also that there are two genera 

 referable to Passiflorese, though they -svill form a separate section of the 

 order, which have a much greater, and even an indefinite, number of perfect 

 stamina, namely, Smeathmania, an unpublished genus of equinoctial Africa, 

 agreeing in habit, in perianthium, and in fruit, with Paropsia ; and Ryanra 

 of Vahl,-f- whicli appears to me to belong to the same family. 



In Passifloreas the stamina, when their number is definite, which is the case in 

 all the genera hitJierto considered as belonging to them, are opposite to the outer 

 series of the perianthium ; a character, which, though of general importance, 

 and here of practical utility in distinguishing them from Homalinae, is not 

 expressed in any of the numerous figiu-cs or descriptions that have been pub- 

 Ushed of the plants of this order. 



Passifloreae and Cucurbitaceae, though now admitted as distinct families, are 

 still placed together by M. de Jussieu ; and be considers the floral envelope 

 in both orders as a perianthium or calyx, whose segments are disposed in a 

 double series.} 



These views of affinity and structure are in some degree confirmed by 

 IlomaUnae, in which both ovarium inferum and superum occur ; and in one 

 genus of which, namely, BlacJcicelUa, the segments of the perianthium, though 

 the complete number, in relation to the other genera of the order, be present, 

 are all of similar textvu-e and form, and are disposed nearly in a simple series. 

 If the approximation of these three families be admitted, they may be consi- 

 dered as forming a class intermediate between Polypetalae and Apetalse, whose 

 principal characters would consist in the segments of the calyx being disposed 

 in a double series, and in the absence of petals ; the different orders nearly 

 agreelno- with each other in the structure of their seeds, and to a considerable 

 deoree in that of the ovarium. 



Tlie formation of this class, however, connected on the one hand with 



* Op. (Hal. 65. + Eclog. 1, p. 51, t. 0. 



+ /tnnal. dtt Miis. iTHisl. Nat. 6, p. 108. 



