SPRING FLORA OF MANHATTAN. 13 



S cwiygdaloides, Anders. Leaves pale beneath, closely and sharply 

 serrate. Catkins terminating small leafy branches of the season. 

 Stamens 8 or more. Wet places, becoming a large tree, common. 



S longifoUa, Muhl. Leaves narrow, remotely denticulate. Stamens 

 2. A shrub or tree, common in low places especially along streams. 



<S. cordaUi, Muhl. Leaves glaucous beneath, closely serrate. 

 Flowers appearing before the leaves. Stamens 2. A tall shrub. Rocky 

 ravines, not common. 



11. BETULACEAE. 



Flowers monoecious, the staminate in catkins. Ovary 2-celled, 

 2-ovuled. Fruit a 1 -seeded nut. Woody plants with alternate, simple 

 leaves. 



OSTRYA, Scop. 



Staminate flowers in close, cylindrical, bracted catkins, from the 

 previous season's wood. The pistillate in short catkins terminating the 

 growth of the season. Fruit an achene, enclosed in an inflated, 

 flattened sac. Leaves 2- ranked. 



O Viryiniana, (Mill ) K. S. P. Leaves oblong, doubly serrate, 

 pinnately veined. Bark twisted. Bluffs, frequent. 



12. FAGACEAE. 



Ditt'ers from Betnlacere in having the ovary 3-celled and 3 or 6 ovuled. 



QUERCUS, L. 



Staminate catkins very slender, interrupted, bractless, from the old 

 wood. Pistillate flowers in little clusters along the new growth. Fruit 

 an acorn. Leaves o-ranked. 



Q. macrocarpa, Michx. J3ark light colored; twigs corky ridged. 

 Leaves sinuate-pinnatifid and lobed. Acorns nearly covered by the large 

 mossy fringed cup. Common. 



Q. prinoides, Willd. Bark light, twigs smooth. Leaves irregularly 

 sinuate-toothed and pinnately veined. Acorns small. Upland woods, 

 common. 



Q. nigra, L. Bark dark, twigs brown. Leaves thickish, 3-lobed at 

 apex, or often lobed along the sides; lobes bristle pointed. Acorn small, 

 about half enclosed in the hemispherical, coarsely scaly cup. Dry hills, 

 from Manhattan eastward. 



Q Rubra, L. Bark dark and smooth, twigs smooth. Leaves lobed, 

 the lobes bristle pointed. Acorn large with a very flat, shallow cup. 

 Hills east of Manhattan, frequent. 



Q tinctoria, Bartr. Resembles Q. rubm but acorn with a top-shaped 

 or hemispherical cup covering the lower half of the acorn. Hills ea.st of 

 Manhattan. 



13. ULMACEAE. 



Flowers moi-e or less polygamous, in umbels or racemes, not in 

 catkins. Trees with alternate, 2-ranked, pinnately veined leaves. Calyx 

 free from the 1-2-celled ovary. 



ULMUS, L. 



Flowers often perfect. Fruit a 1-2-celled samara, winged all around, 



