468 PATAGONIAN EXPEDITIONS I BOTANY. 



c. Carpels 2-ovuled, becoming a mass of drupelets. No outer calyx. 



4. Rubus, p. 469. 



C2. Carpels i-ovuled, becoming achenes. Mostly an outer calyx. 

 d. Seeds pendulous. Achenes nut-like ; style deciduous. 



e. Carpel-bearing receptacle becoming large and juicy. 5. Fragaria, p. 470. 

 <?2. Carpel-bearing receptacle little enlarged in fruit, dry and colorless. 



6. Potentilla, p. 470. 

 d2. Seeds erect. Style usually persisting. Flowers 5-merous. Receptacle flat. 



7. Geum, p. 471. 



b2. Floral axis goblet-shaped, completely enclosing the 2-more carpels, usually hardening in 

 fruit. Filaments with slender base, not narrowing above. Sepals 4, rarely 3 or 5. Petals 

 none. Stamens sometimes few or 1-2 ; carpels few. 

 c. Outer calyx leaves 4-5, alternating with the sepals. Style basal. Carpels 1-4. 



Leaves broad, simple, usually lobed. 8. Alchemilla, p. 472. 



c2. No outer calyx, nor petals. Floral axis spiniferous in fruit, but not a circle of spines. 



Leaves often pinnately divided. 



d. Spines small and short, i under each sepal. Carpel I. Flowers small, solitary, 

 axillary. Fruit a white berry. Small shrubs. 9. Margyricarpus, p. 473. 



d2. As Margyricarpus, but fruit dry, 4-winged. 10. Tetraglochin, p. 474. 



d$. Spines on the angles of the fruit, or only I strong barbed spine under each sepal. 

 Carpels 2. Flowers in erect spikes or heads. Mostly herbs. 



1 1. Acczna, p. 475. 



A^. Carpels solitary, not adnate to the hollowed receptacle. Styles terminal. Ovary with 2 

 pendulous ovules, becoming a drupe. Trees or shrubs, with simple stipulate leaves. 



12. Prunus, p. 485. 



i. SPIRAEA Linn. 



Shrubs or herbs, usually with pinnately divided leaves, and racemose 

 or paniculate, perigynous fawers, 4 5-lobed calyx, 45 petals, and 2060 

 stamens, with didymous anthers. Carpels 1-8, mostly 5, not united. 

 Ovules 2-many. Follicles usually dehiscing by one suture. 



Species 60, chiefly in N. Temperate parts of Old World ; a few in W. 

 Amer. 



S. MAGELLANICA Poir. 



Leaves petiolate, exstipulate, lanceolate, unequally serrate, nervose. 

 Racemes terminal, subsimple. Flowers white. 



Magellan. 



(The only representative of the genus in the S. Hemisphere. S. ar- 

 gentea is in New Granada.) 



2. CYDONIA Tourn. Quince. 



Beautiful shrubs, with simple, deciduous leaves and large, scarcely ped- 

 unded flowers. Stamens 20 or more. Carpels 5, with numerous seeds 



