40 Transactions of the South African Philosophical Society. 



which, however, through the study of the development of the 

 flower, becomes an absolute fact, and thus justifies us in uniting 

 Mesembrianthemum with other truly apetalous plants, such as 

 Aizoon, Galenia, &c, into one natural order, the Aizoacece. 



c. The inflorescence of Galenia spathulata, Fenzl. 



Galenia spathulata is a more or less prostrate herb which is also 

 a common weed in Grahamstown gardens. When examining its 

 flowering region, it appears at first sight as if here the universal 

 axillary branching of flowering plants did not obtain. If we examine 

 a strongly developed shoot, it appears as if its branches arise by 

 the side of the leaves, and that, therefore, they are without bracts. 

 But by comparing it with the inflorescence of Mesembrianthemum 

 angulatum, we find that we have to deal here with a similar 

 inflorescence, although it is different in some details. In M. 

 angulatum we may assume that the /3 leaf adheres to its axillary 

 shoot for some distance, and that in this way the ordinary decussate 

 arrangement of leaves in the species of Mesembrianthemum is 

 altered into the alternate arrangement which we meet with in 

 its inflorescence. We may further assume that the axis of its 

 axillary shoot adheres to the axis of its parent shoot up to 

 this point. If, on the other hand, both a and fi adhered to 

 the axis of their axillary shoots for some distance while the 

 axis of the parent shoot (bearing flower I) remained short, we 

 should have an inflorescence exactly the same as that of Galenia 

 spathulata. Here again the shoot in the axil of ft is favoured in 

 growth, and, throwing the terminal flower aside, places itself into 

 the prolongation of the parent shoot. It will now be seen why the free 

 shoot in the axil of «' is found by the side of /3 and separated from 

 it by a angle of 90°, while «' is found as the first leaf on this free 

 shoot. The ground plan of this inflorescence is exactly the same as 

 in M. angulatum, and even the further complication in the latter, 

 namely, the formation of accessory shoots in the axils of both « and 

 P occurs not infrequently. Thus we find a further common feature 

 between Galenia and Mesembrianthemum in the fact that even in 

 these highly complicated inflorescences the design, so to speak, is 

 exactly the same. 



Explanation of Figures : — 



Plate I. — 



Fig. 1. — Disa (D. patula T). 



A. Peloric flower (magnified), all parts spread out. s = sepal, 

 p = petal, st = stamen, st' = staminode, stg = stigma. 



