GERMINATION OF TREES AND SHRUBS 307 



P^AGALES 



BETULACE^. 



The literature of the order was cited by us last year.^^ 



Corylus amerkana Walt. Hazelnut. Seeds collected alojig 

 Cedar river, Henry county, September 28, 1917. Stratified out of 

 doors. Placed March 19, in greenhouse, germinated May 1, 25 

 per cent. Germination hypog"a?ous, several brown roots, a few 

 small scales on the stem, leaving soars. Seedling studied has 

 ]nultiple stems, green in color, stem glandular-pubescent. Lower 

 leaves small, ovate, lanceolate, bright green aoove, pale beneath, 

 conspicuously reticulately-veined, slightly pubescent on both sur- 

 faces, margins dentate; teeth glandular tipped. Stipules small, 

 pointed, pale in color, soon falling. Trichomas long, occurring 

 singly, slender, colorless, acute-pointed. Each dentation of leaf 

 tipped with a reddish gland. 



Lubboek^^ describes germination of Corylus Avellana. 



Ostrya virgiuana (]\rill) K. Koch. Hornbeam or Ironwood. 

 Lubbock^'* describes the germination of the related genus Carpi- 

 nus. 



Seeds collected on Cedar river, Henry county, Iowa, fall of 



1917. Wintered out of doors, planted in greenhouse, March 14, 



1918, germinated April 10, 1918. Germination is not uncommon 

 in the field, especially in leaf mould under trees. Germination 

 epigffious. Hyix)cotyl (the stem below the cotyledons) terete, 

 reddish, glandular-pubescent, the roots delicate broAvnish, giving 

 off numerous roots. Cotyledons oval, auricled at the base, 

 shortly petiolate, fleshy, yellowish below. Leaves alternate. First 

 leaf oval, coarsely dentate, nearly smooth above, a few hairs 

 along the midrib, scattered hairs elsewhere, on both surfaces. 

 Stipule® green, pointed, bearing trichomevS. Stem above the cot- 

 yledons with scattered hairs. Trichomes simple, slender, vary- 

 ing from short to long, straight or slightly curved, pointed. The 

 walls thin, smooth. Basal portion somewhat enlarged. 



Betida lutea ]M'iclix f. Yellow or Gray Birch. Stratified outside 

 for wintering. Removed to greenhouse March 14, 1918, germi- 

 nated April 13, 1918. Hypocotyl smooth, cotyledons small, about 

 3 mm. by 4 mm., oval, entire, flesh.y, surface granular in appear- 

 ance. Under surface pale. First leaves not distinguishable in 

 appearance from those of B. papyrifera. Leaves alternate, broad 



i-Pammel, L. H., and King, C. M., the germination and juvenile forms of 

 some oaks: Proc. Iowa Acad. Science, 2}, pp. 367-391. 



'°A contribution to our knowledge of seetilings, 2, pp. 53^-539. 

 "A contribution to our khowledge of seedlings, 2, pp. 532, f. 667. 



