DICOTYLEDONOUS PLANTS 107 



(b) Carpels 2-seeded (except in some cultivated varieties) ; 



seeds without pulp. Fruit 5-celled. Pyi'us, IV. 



(c) Carpels 2-seeded ; fruit 10-celled. Amelanchier, V. 



2. Fruit not evidently a pome or not at all so. 



(a) Trees or shrubs. Fruit appearing like a stone-fruit, with 



a stone usually of 2-5 bony 1-seeded carpels united. 



Crataegus, VI. 



(b) Herbs. Fruit consisting of numerous very small akenes 



collected on a fleshy, eatable receptacle. Fragaria, IX. 



(c) Trees or shrubs. Fruit a simple stone-fruit (plum or 



cherry). Prunus, XIII. 



I. PHYSOCARPUS, Maxim. 



Shrubs. Leaves simple, palmately veined and lobed, pet- 

 ioled. Flowers white, in terminal corymbs. Calyx spreading, 

 5-lobed. Petals 5. Stamens numerous. Pistils 1-5, short- 

 stalked, stigma terminal ; ovaries becoming inflated at matu- 

 rity, 2-4-seeded, splitting open.* 



1. P. opulifolius, Maxim. Ninebark. A spreading shrub 3-6 ft. 

 high, the old bark separating into thin strips. Leaves petioled, 

 broadly ovate or rounded, often heart-shaped, 3-lobed, the lobes doubly 

 crenate-serrate ; stipules deciduous. Corymbs terminal, peduncled, 

 nearly globose, downy, many-flowered. Pedicels and caly:s. nearly 

 smooth. Follicles 3-5, much longer than the calyx, smooth and 

 shining, obliquely tipped by the persistent style. Banks of streams, 

 and often cultivated.* 



n. SPIREA, L. 



Shrubs with simple leaves. Flowers perfect, in terminal 

 or axillary racemes or panicles. Calyx 5-cleft, persistent. 

 Petals 5. Stamens numerous. Pistils usually o, free from 

 the calyx and alternate with its lobes. Follicles not inflated, 

 2-several-seeded.'* 



1. S. salicifolia, L. Willow-leafed Spirea. Shrubs 2-5 ft. 

 high, branches smooth ; leaves lanceolate to oblong-ovate, smooth 

 or nearly so, sharply serrate, base usually wedge-shaped, pale beneath ; 

 stipules deciduous ; flowers white or pink, panicle dense-flowered ; 

 follicles smooth. On low ground.* 



