GROUP V. ANGIOSPERM.E : MOXOCOTYLEDDXES. 



483 



irrespectively of the numerous intermediate forms which are to be 

 found, such a view is untenable when it is barne in mind that here 

 the ovaries are invariably situated below 

 the stamens, while in a flower they are 

 invariably above them. 



The usually sympodial stem may be un- 

 derground, a tuber, or a rhizome, or it may 

 be aerial ; in the latter case it often climbs, 

 clinging to trees by means of aerial roots. 

 The leaves are either alternate and dis- 

 tichous or, more often, spiral with a diver- 

 gence of f . They are rarely narrow, linear, 

 or ensiform, and commonly consist of leaf- 

 base, petiole, and blade ; the venation is 

 reticulate, and the leaf often exhibits a 

 more or less complicated segmentation. 

 Laticiferous sacs or cells (see p. 99) occur 

 in some families of the order, as do also 

 sclerotic cells (see Fig. 98 A, p. 120). 



The principal families are : 



FIG. 295.-Spadixof ,4 runt 

 maculatum (nat. size) : / 

 macrosporangiate, a micro- 

 sporangiate, and b rudi- 

 mentary flowers ; c the up- 

 per club-shaped end of the 

 spadix. 



Fam. 1. Pothoidece : without either laticiferous 

 or sclerotic cells : flowers usually $ , with or 

 without a perianth. This family includes a 



number of genera, such as Pothos, Anthurium, Acorus. The only member 

 which occurs in Britain is Acorus Calamus, the Sweet Flag, which grows 

 on the margins of ponds and rivers : its subterranean rhizome bears long 

 ensiform alternate leaves, crimped at the edges ; its flowering-shoot is 

 triquetrous, bearing a terminal spadix which is, however, displaced to one 

 side by the spathe which developes so as to form a continuation of the 

 long axis of the flowering-shoot : the spadix is densely covered with 

 flowers (Fig. 294). 



Fam. 2. Caltoidece: with straight rows of laticiferous cells: fli>\v.-r> 

 usually $ , with or without a perianth : leaves never sagittate. No 

 member is indigenous in Britain : Calla palustris occurs in the marshes of 

 Northern Europe; it has a white spathe and parallel- veined leaves. 



Fam. 3. Philodendroidece : with straight rows of laticiferous cells: 

 flowers diclinous, without a perianth : stamens usually connate : leaves 

 generally parallel-veined. Zantedeschia (Calla or Richardia) cdhiopica, 

 with a white spathe, is commonly cultivated under the name of the 

 Trumpet Lily. 



Fam 4. Aroidece: with straight rows of laticiferous cells: flowers 

 diclinous: usually without perianth. Arum maculatum, the Cuckoo-pint 

 or Lords and Ladies, is a British plant, common in wood and hedges : the 



