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, or 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. SALICACE.^. 'Willow Family 



DioBcious 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-like or often small and soon deciduous. 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 \yillow are found growing wild in the 

 northeastern and north central states, but they are very hard, even 

 for botanists, to identify.] 



