132 THE FLORA OF THE ALPS 



ceolate, stipules ovate-lanceolate, deciduous. S. Caprea, 

 L., Sallow; leaves elliptic, tomentose beneath; a small 

 tree. vS. aurita, L. ; leaves obovate-oblong, catkins short, 

 dense-flowered. S. viminalis, L., Osier; leaves linear- 

 lanceolate, catkins sessile, branches very flexible. 5. 

 purpurea, L. ; leaves linear-lanceolate, catkins with purple- 

 black scales. 



DIVISION II. MONOCOTYLEDONES OR ENDOGENS. 



Stem, when perennial, with irregularly dispersed woody 

 bundles, not in concentric circles, with no central pith 

 or separable bark ; leaves usually parallel-veined ; sepals, 

 petals, and stamens usually in threes ; embryo with one 

 cotyledon. 



CLASS V.PETALOID^E. 



Calyx and corolla usually both present and coloured. 

 (Orders LXXXIV.-XCIX.) 



Order LXXXIV. HYDROCHARIDEyE. 



Aquatic herbs with floating or submerged opposite or 

 whorled leaves; flowers usually unisexual and dioecious, 

 buds enclosed in spathes ; perianth 6-parted, coloured or 

 inconspicuous; stamens 3-12; ovary i-6-celled. A very 

 small order, widely distributed ; not alpine. 



i. HYDROCHARIS, L. 



Dioecious ; sepals 3, green ; petals 3, white ; stamens 

 1 2, some of them imperfect ; ovary 6-celled ; styles 6 ; 

 leaves orbicular, entire. 



