*94 



Fam. 21. Aizoaceae. 



(Plates 48—54 and 56.) 



Herbs, half-shrubs or shrubs of various habit. In- 

 florescence generally cymose; occasionally flowers solitary. 

 Flowers bisexual, regular. Perianth simple (pseudopetals 

 in Limeum^ 0?ygia, MesembrianthemufnS^ 4 — 5 -parted; 

 segments free or joined into a tube, often coloured on the 

 inner side. Stamens 5 or by "dedoublement" more nu- 

 merous, the groups alternating with the perianth- or calvx- 



groups alternating witn tne penantn- or caiy; 



segments. Ovary 2- or more-celled (exc. Adenogrammd)\ 

 ovules 2 or more in each cell (exc. genera 4, 5 and 6). 

 Fruit a capsule or nut or nutlets, rarely pulpy as in a few- 

 species of Mesej?ibria?ithemum. Seeds with a peripheric 

 embryo and central farinaceous perisperm. 



The family' is not easily defined, as some of its 

 members approach Phytolaccaceae so closely, that certain 

 authors* refer the connecting genera Adcnogramma, 

 Polpoda, Limeiwi^ Psammot7~opha and Giesekia to that 

 family, while Sonder'J~ places them together with other 

 Mollugineae in Caryophyllaceae. Whichever course 

 is adopted, some genera will appear to occupy an abnormal 

 position. 



The genus Mescmbriaiithei?iuvi^ at first sight, would not 

 be called monochlamydeous, as its flowers possess numerous 

 and very conspicuous petaloid organs [pseudo-petals). 

 It has been shown, however, that these petaloid organs are 

 genetically of the same origin as the stamens, having been 

 derived from the same tissue which in other genera forms 

 5 or more stamens. The two sub-families are very different 

 in habit, but show a gradual transition in their floral 

 structure from a simple to a highly complex organisation. 



* Pax, in Engl. Pflanzenfam. in, i //, p. 37. 

 + Sonder, Flor. Cap. i, 121. 



