216. QUEKCUS MACDOXALDI MAcDoNALD OAK. 39 



yellow-brown color, conspicuously tuberculate, pub^cent, and the thin pointed 

 tips of the scales closely appressed. 



The specific name, macdonaldi, is given in compliment to Hon. James M. Mac- 

 Donald, a promoter of botanical research in California. 



The ^lacDonald Oak is generally considered a small tree and rarely 

 surpassing L>O ff. (6 m.) in height or 1 ft. (0.30m.) in diameter of 

 trunk and such we understand to be its habit on the island of Santa 

 Cruz where it was discovered, but on the island of Santa Catalina I 

 have seen a tree of the species 5 ft. (1.50 m.) in diameter of trunk 

 with wide top of long horizontal branches shading an area 75 ft. 

 across. It is the largest tree on the island. 



HABITAT. The islands of Santa Cruz and Santa Catalina, off the 

 coast of southern California, with a variety (elengantula) of rather 

 doubtful tenure on the adjacent mainland. 



PHYSICAL PROPERTIES. Wood of the MacDonald Oak is heavy, 

 hard, strong, with large medullary rays and annual rings well defined 

 by the arrangement of large open ducts. The heart-wood is of a rich 

 brown color, but only found in trunks of considerable age, and the 

 abundant sap-wood is creamy white. 



TSES. This oak is too rare and local to be applied to any particu- 

 lar use. 



NOTE. There is a disposition with some botanists to consider this 

 tree as merely a form of the Quercus dumosa, but after a careful 

 study of the tree on Santa Catalina island I cannot agree with that 

 opinion 1 . Its deciduous nature and stately form, as there seen, with 

 larger leaves, some almost suggesting the leaves of the eastern White 

 Oak, at once impress you with its distinctness from the humble per-, 

 sistent-leaved and shrub-like Q. dumosa which covers the neighboring 

 slopes. It is true that some of its smallest leaves do approximate in 

 appearance some of the larger leaves of the Q. dumosa, but the 

 resemblance is no more marked here than we see between the leaves 

 of various other trees known to be distinct. 



ORDER BETULACEJE : BIRCH FAMILY. 



Leaves simple, alternate, straight-veined and furnished with stipules which 

 fall away early. Flowers mostly nak:ed. monoecious, both kinds in catkins 2 or 3 

 together under a 3-lobed bract or scale. Sterile flowers with distinct stamens 

 and 2-celled anthers. Fertile flowers with two thread-like stigmas, and a 2-celled 

 ovary, each cell containing 2 pendulous ovules, becoming by abortion in Fruit, a 

 small, 1-celled, 1-seeded nutlet, often with membranous wings; seed anatropous, 

 albumenless, with flattish, oblong cotyledons which become foliaceous in 

 germination. 



Trees or shrubs, with bark whicli separates more or less easily into thin layers. 



GENUS ALNUS, TOURNEFORT. 



Leaves deciduous, alternate, generally serrate, pinnately veined, furnished with 

 caducous stipules which inclose them in the bud, fall in autumn while still green 



