THE ANDHCECIUII OF MENIZELIA. 213 
separating them, as Payer has done, into a distinct Order from the 
Louses, The researches of Payer have shown that in these latter the 
androecium consists of five compound stamens superposed to the sepals. 
Thus far, therefore, the analogy between the andrcecia of the two groups 
would hold good. In the Loasece, however, the evolution of the sta- 
ininal lobes is centrifugal as regards the axis, while that in the Meui^ 
zeliece is centripetal. This difference is certainly a very striking one, 
but it may fairly be doubted if it is sufBcient to separate into distinct 
Orders two groups of genera so closely allied in all other respects. The 
centripetal development of lobes in the compound stamens of the Mp'- 
iacece, to which I have compared that of the Me?itzeliece, was considered 
by Payer analogous to the basifugal evolution of leaMobes in ordinary 
leaves, wliile the commoner centrifugal development of staminal lobes 
such as tliat in Hypericum^ Tilia^ etc., he compared to the basipetal 
evolution of leaf-lobes. In a note, however, to my paper "On Diplo- 
stemonons Flowers " in last year's volume of the Society's Transactions, 
I ventured to question the correctness of the distinction which Payer 
has sought to draw between the two cases, as follows, — " Payer has 
somewhat hastily, I think, compared the componnd stamens in the 
Myrtaccm to leaves with lobes developed from base to apex, or basifu- 
gally (' Organogenic,' p. 718). His figures, however, distinctly ludi- 
eate that here, as in the ordinary form of compound stamens, there is 
a mesial stamen or lobe of the compound stamen, from which, as" a 
point of departure, the evolution of the other stamens extends; and it 
appears to me improbable that a basifugal succession of lobes should 
be initiated by the development of a lobe in the middle line at the bf 
of the compound stamen- The phenomenon seems more naturally ex- 
plained by supposing that the first-developed lobe of the Myrtaceous 
compound stamen corresponds to the first- developed or terminal lobe in 
the ordinary form, in which case the evolution in both cases would be 
basipetal; the only difference between the two being that, while in tlie 
Hypericacece, etc., the lobes are developed on the back or outer face of the 
rachis of the compound stamen (the staminal cushion), in the Myrtacece 
they appear on its front or inner face. In confirmation of this opinion, 
T may refer to the highly-developed staminal groups in Melaleuca pur - 
purea^ where, in each phalanx, the stamens evidently proceed from the 
inner face of the flattened and elongated rachis."* If this explanation 
» Transact. Bot. Soc. Edin., roL viii. part 1, p. 100. 
