382 



CORYLUS 



AA. Husk tubular, of connate 

 bracts. 



B. Involucre campanulate, with 



large, dentate, spreading lobes. 



Pontica, Koch. Shrub: Ivs. cor- 

 date, roundish ovate or broad-oval, 

 doubly serrate : involucre finely 

 pubescent, with few glandular hairs 

 at the base: nut large, broad -ovate. 

 W. Asia. P.S. 21:2223-4 as C. 

 Column. From this species the 

 Cob Nuts seem to have originated; 

 also the Spanish Nuts are probably 

 mostly cross-breeds between this 

 species and C. Avellana or C. 

 maxima, or between the two latter 

 species. 



BB. Involucre narrowed above 

 the nut into a beak. 



maxima, Mill. (C. tubulbsa, 

 Willd.). Shrub, sometimes small 

 tree, to 30 ft. : Ivs. cordate, round- 

 ish-ovate, slightly lobed and doubly 

 serrate, 3-6 in. long : involucre 

 finely pubescent outside: nut ob- 

 long, large ; kernel with thin red or 

 white skin. S. Eu.-Var. pur- 

 purea, Hort. (C. Avellana pur - 

 purea, Hort.). Lvs. deep pur- 

 plish red. Many varieties, with 

 large nuts, known as Filberts 

 or Lambert's Filberts. 



rostrata, Ait. Figs. 561, 562. 

 Shrub, 2-6 ft. : Ivs. rounded or 

 slightly cordate at the base, oval 

 or obovate, densely serrate and 

 sometimes slightly lobed, nearly 

 glabrous at length, except spar- 

 ingly pubescent on the veins be- 

 neath, 2>-4 in. long : involucre 

 densely beset with bristly 

 hairs, beak long and narrow : 

 nut ovoid, % in. long. East- 

 ern N. Amer., west to Minn, 

 and Colo. G.F. 8:345. B.B. 

 1:508. 



Calif 6rnica, Rose. Fig. 

 562. Allied to G. rostrata. 

 Shrub, to 20 ft. : Ivs. more 

 villous beneath : involucre 

 with a short beak, which is 

 often flaring and sometimes 

 torn. 



C. heterophylla, Fisch. Allied 

 to C. Avellana. Lvs. more lobed: 

 involucre large, spreading, longer than the 

 fr., with large, triangular, nearly entire 

 teeth. N. China, Jap. (Offered by import- 

 ers.) O.Mandsfttirica.Maxim. Allied toC. 

 rostrata. Lvs. large and broad: involucre thickly 

 beset with strong brown bristles ; tube slightly 

 enlarged at the apex, and laciniately divided into 

 narrow, entire segments. Amurland, Jap. C. 

 Sieboldi, Blume. Allied to C. rostrata. Lvs. nar- 

 rower: involucre densely coated with loosely ap- 

 pressed, less bristly hairs; beak long and nar- 

 rowed toward the end. A.G. 12:267. ALFRED REHDER. 



CULTURE FOR THE NUTS. Hazel, Filbert, Cobnut. 

 The three native Hazels, C. Americana, C. Califor- 

 nica and C. rostrata, have been sparingly introduced 

 to cultivation, but have not developed varieties 

 worthy of naming or propagating. The foreign species, 



C. Avellana, C. Pontica and C. maxima, were intro- 

 duced along the Atlantic seaboard at an early day, and 

 are maintained in gardens throughout the New England 

 and Middle Atlantic states. Efforts to make extensive 

 culture profitable in the eastern United States have 

 hitherto failed, probably from attacks of a fungous dis- 

 ease, Cryptospora anomala, common on C. Americana, 

 but not specially injurious to that species. It attacks 

 and destroys the young branches, and later the older 

 branches and trunk, without killing the root. Bordeaux 



562. 



Filberts and 

 Hazels. 



Natural size. 



1, American-grown 

 Filbert; 2, Cory- 

 lus Americana, 

 form with open invo- 

 lucre; 3, (7. Americana, 

 closed involucre; 4.C. 

 Califomica; 5, C. ros- 

 trata. 



CORYLUS 



mixture has been suggested as a 

 preventive, but recorded success- 

 ful experiments are lacking. Ex- 

 perimental plantings on the Pacific 

 slope indicate greater success with 

 imported Hazels there than in the 

 east, but they have not developed 

 commercial importance. 



The requirements of the Hazel in 

 America, so far as known, are: 

 moderately rich, well-drained soil; 

 absence of C. Americana from vi- 

 cinity ; freedom from mild periods 

 in winter and late frosts in 

 spring. It is specially subject 

 to frost injury, as both stami- 

 nate and pistillate catkins de- 

 velop in fall and quickly swell 

 and open under the influence of 

 mild weather in winter. The 

 staminate catkins commonly 

 bloom first. If they are de- 

 stroyed by frost, fertilization 

 can be accomplished by sus- 

 pending branches from trees 

 from other localities, even of 

 other species of Corylus. 



Propagation by seeds is easily 

 done by stratifying in fall and 

 planting in nursery rows in 

 early spring. Seedlings vary 

 exceedingly, and varieties are 

 perpetuated by budding, graft- 

 ing, suckers or layers ; com- 

 monly by the last two methods. 

 A considerable supply of well 

 rooted suckers can be obtained 

 from fruiting trees by banking 

 in summer with rich soil or 

 stable manure to promote root 

 formation. Stools for layering 

 should be heavily manured to force 

 long and slender shoots suitable 

 for bending. These should be 

 staked down in winter or spring 

 and covered wifh earth. They may 

 be removed to nursery rows or 

 orchard at end of first season. 



Planting should be at a distance 

 of 10 to 20 feet in well prepared soil, 

 in fall or spring. Ground may be 

 cropped with low growing, culti- 

 vated plants while trees are young, 

 but should be maintained in good 

 tilth and fertility. 



Pruning is of special importance 

 with this nut. Trees are usually 

 headed at height of 1 or 2 feet, 

 though often permitted to take nat- 

 ural form, which is that of a many- 

 stemmed bush, designated a"stool." 

 Trees are classified according to 

 height of clear trunk into "stan- 

 dard, ""half standard," and "dwarf 

 standard." A short trunk, with 

 vase-form head of six or more 

 branches, is preferred. Suckers 

 should be kept down, unless desired 

 for propagation. Both sexes of blos- 

 soms are borne on 1-year-old lateral 

 twigs or spurs. March or April, 

 after flowers of both sexes have 

 bloomed, is considered best 

 time for pruning, as unneces- 

 sary sacrifice of pollen 

 can thus be avoided. 

 Strong shoots should 

 be headed back to 

 promote spur forma- 

 tion, and old wood 

 that has borne fruit 

 should be removed 

 annually. 



