KNAWEL TRIBE PERSICARIA TRIBE 247 



Natural Order LXVI 



SCLERANTHACE.E. The Knawel Tribe 



Perianth tubular, 4- or 5-cleft ; stamens 5-10, inserted into th- 

 mouth of the tube ; ovary 1, superior, i-celled ; styles 2 or 1, 

 notched at the summit ; fruit enclosed within the hardened tube 

 of the perianth. Only one British genus belongs to this Order, 

 containing but two species, which are small, inconspicuous weeds, 

 with wiry, much-branched stems, scanty foliage, and small, greenish 

 flowers, remarkable only for the chaffy edge of the perianth. 



I. Scleranthus (Knawel). Calyx 5-cleft, contracted at the 

 mouth of the tube ; petals o ; stamens 10, rarely 5 ; styles 2 ; fruit 

 i-seeded, covered by the hardened calyx. (Name from the Greek, 

 scleros, hard, and anthos, a flower, from the hardness of the calyx.) 



1. Scleranthus {Knawel) 



1. S. annua (Annual Knawel). Calyx, when in 

 fruit, spreading, acute, with a narrow, whitish 

 margin ; root annual. A small plant, 2-4 inches 

 high, with numerous tangled stems, awl - shaped 

 leaves, and green flowers, which grow either in 

 the forks of the stems or in terminal tufts. 

 Cornfields, especially on gravelly soil ; common. 

 Fl. July to November. Annual. 



2. 5. perennis (Perennial Knawel). Stems pros- 

 trate ; calyx-leaves blunt, with a broad margin. 

 Dry, sandy fields in the south and east of Eng- 

 land ; very rare. Perennial. Scleranthus Annua 



(Annual Knawel) 



Natural Order LXVII 



POLYGONACE.E. The Persicaria Tribe 



Flowers often bearing stamens only, or pistils only. Perianth 

 deeply 3-6 parted, often in two rows ; stamens 5-8, from the base 

 of the perianth ; ovary 1, not attached to the perianth ; styles 2 

 or 3 ; fruit, a flattened or triangular nut. Herbaceous plants, 

 distinguished by the above characters and by bearing alternate 

 leaves, furnished at the base with membranous stipules, which 

 encircle the stalk. The perianth is often coloured ; and as the 

 flowers, though not large, are numerous, and grow in spikes or 

 panicles, many of them are handsome plants. Others, as the 

 Dock, are unsightly weeds ; they are found in all parts of the 

 world, from the Tropics to the Poles, and at all altitudes. The 

 properties residing in the leaves and roots are very different, the 

 former being acid and astringent, and sometimes of an agreeable 



