14 SPRING FLORA OF MANHATTAN. 



which ripens in early spring. Flowers appearing before the leaves, in 

 clusters on the old wood. 



U. Americana, L. Flowers slender pedicelled. Fruit hairy 

 margined. Leaves smooth above. Twigs brown, smooth or nearly so. 

 Woods, common. 



U. pubescens, Walt. Flowers nearly sessile. Fruit smooth. Leaves 

 rough above. Twigs gray, scabrous. Woods, common. 



CELTIS, L 



Flowers racemose from the growth of the season. Fruit a drupe. 



V. occidentalism L. Leaves taper-pointed, nearly smooth, veiny. 

 Bark gray and rough-warty. Low woods, frequent. 

 14. MORACEAE. 



Flowers unisexual. Calyx becoming fleshy in fruit, enclosing the 

 achene. Woody plants with milky juice. 



MORUS, L. 



Flowers in eatkin-like spikes; the fertile spike resembling in fruit a 

 blackberry. 



M. rubra, L. Leaves cordate, serrate, often deeply lobed Twigs 

 smooth, light gray. Low woods, frequent. 



15. URTICACEAE. 



Flowers unisexual. Ovary 1-celled. Fruit an achene. Herbs. 

 PARIETARIA, L. 



Flowers in bracted cymose clusters in the axils of the alternate, 

 entire, 3-ribbed leaves. 



P Pennsylvanica, Muhl. A low, simple stemmed, inconspicuous 

 annual, with thin, roughish leaves. Moist, shady places, common. 



16. SANTALACEAE. 



Flowers apetalous. Calyx 4-5-cleft, adherent to the 1-celled ovary. 

 Stamens as many, inserted opposite the lobes. Fruit 1 seeded. Style 

 one. Leaves entire. 



COMANDRA, Nutt. 



Low perennials with alternate, sessile leaves and whitish (lowers in 

 terminal clusters. 



C. umbellata, (L.) Nutt Stem erect (1-2 dm). Leaves oblong. 

 Prairie, common. 



17. POLYOGONACEAE. 



Flowers apetalous. Calyx mostly 5 6-cleft, persistent. Stamens 

 several. Ovary 1-celled, 1-ovuled, forming in fruit an achene. Styles 

 2-3. Herbs with alternate, entire leaves and sheathing stipules. 



RUMEX, L. 



Sepals 6. the 3 outer refiexed in fruit, the inner enlarging and 

 enclosing the achene, then called valves. Stamens 0. Achene 3-angled. 

 Flowers small, green, in close whorls, forming a terminal panicle. 



R. Acetosella, L Low and slender, dioecious. Leaves halberd- 

 shaped or the upper linear. Valves small. Meadows, infrequent. 



/?. altissimus, Wood. Taller (-i-1 m). Leaves oblong-lanceolate, not 



