48 KEY AND FLORA 
few grains, held together in masses by cobweb-like threads. 
Ovary 1-celled, containing many (sometimes more than a mil- 
lion) very minute ovules. 
The family is a difficult one, and most of the genera are so 
rare that specimens should not be collected in large numbers 
for class study. Two of the most familiar genera are Cypri- 
pedium, ov Lady’s Slipper, and Spiranthes, or Lady’s Tresses. 
Many of the genera are tropical air plants. 
SUBCLASS II. DICOTYLEDONOUS PLANTS 
Stems composed of bark, wood, and pith; the fibro-vascular 
bundles in rings; in woody stems which live over from year 
to year, the wood generally in annual rings, traversed at right 
angles by medullary rays. Leaves netted-veined. Parts of the 
flower usually in fours or fives. Cotyledons 2 (rarely none). 
14. SALICACER. Wirttow Famity 
Dicecious trees or shrubs, with flowers in catkins, destitute 
of floral envelopes. Fruit a 1-celled pod, with numerous seeds, 
provided with rather long and silky down, by means of which 
they are transported by the wind. 
I. SALIX L. 
Shrubs or trees, branches usually very slender. Buds with 
single scales. Leaves usually long and narrow; stipules some- 
times leaf-hke or often small and soon deciduons. Bracts of 
the catkins entire. Staminate catkins erect or drooping 
(Fig. 10); staminate flowers with 2-10, mostly 2, distinct or 
united stamens. Pistillate catkins usually erect (Fig. 10); 
flowers with a small gland on the inner side of the bract; 
stigmas short, 2-lobed. Capsule 2-valved.* 
[Thirty or more species of willow are found growing wild in the 
northeastern and north central states, but they are very hard, even 
for botanists, to identify.] 
