Jones: Flora of Illinois, 83. Rosaceae 155 



Mountain-ash. Often mistaken for the following species 



S. aucuparm L. 



1. Winter buds glabrous, glutinous, 1-2 cm. long; leaflets lanceolate, acumi- 

 nate, finely serrate, 5-9 cm. long; flowers 5-6 mm. broad; fruits 4-6 mm. 

 in diameter; rocky woods, rare; near Oregon, Ogle Co., June 2, 1888, M. 

 B. Wake. American Mountain-ash S. amerkana Marsh. 



15. Aronia Medic. — Chokeberry 



A. melanocarpa (Michx.) Ell. Moist sandy woods, and bogs, n. 111. May- 

 June. Other species have been recorded from 111., but all specimens we have 

 seen are of this species. 



16. Pyrus L. — Pear 



P. communis L. Cult, and found occasionally as an escape in woods or 

 along roads; native of Eur. May. 



17. Malus Mill.— Apple 



1 Calyx glabrous outside (rarely somewhat villous) ; leaves glabrous or nearly 

 so; mature fruit 1-3 cm. in diameter; woods. Apr.-May. [Pyrus coronaria 

 L.; M. glance scens Rehd.; M. lancifolia Rehd.} Wild Sweet Crab-apple 

 M. coronaria (L.) Mill. 



1. Calyx tomentose; leaves pubescent beneath, at least along the veins. 



2. Leaves irregularly toothed, notched, or lobed, narrowed at the base; calyx- 

 lobes erect or spreading; fruit 2-4 cm. in diameter; woods, common. 



May. [Pyrus loensis (Wood) Bailey} Iowa Crab-apple 



M. ioensis (Wood) Britt. 



2. Leaves crenate-serrate, rounded or cordate at base; calyx-lobes usually 

 reflexed at anthesis; fruit larger; cult., and not infrequently wild; native 

 of Eur. and w. Asia. Apr.-May. [Pyrus malus L.; M. sylvestris of 

 auth., not Mill.] Apple M. pumila Mill. 



18. Crataegus L. — Hawthorn 



1 . Leaves cuneate at the base, widest near the middle or toward the apex. 

 2. Blades usually widest above the middle, mostly obovate or spatulate, the 

 margins merely serrate or only obscurely lobed; calyx-lobes entire. 

 3. Leaves firm, glabrous, glossy above, not impressed-veined. 



4. Pedicels glabrous; nutlets 8-9 mm. long; pastures and open woods, 

 especially near streams, common. May-June. [C. arduennae Sarg.; 

 C. attenuata Ashe; C. strongylophylla Sarg.; C. trahax Ashe} 

 Cockspur Thorn C. crusgalli L. 



4. Pedicels pubescent; nutlets 4-5 mm. long; low ground. Type loc. : 



Wady Petra, Stark Co.; known also from Peoria and Marion 



counties. [C. palmeri Sarg.} C. pratensis Sarg. 



3. Leaves thinner, dull, impressed-veined above. 



5. Pedicels and leaves glabrous; open woods, usually along streams, n.- 



centr. 111. May-June. [C. dispersa Ashe; C. pausiaca Ashe; C. 



peoriensis Sarg.; C. praestans Sarg.} 



.C. cujieiformis (Marsh.) Egglest. 



