POLLEN-GRAINS AS SOURCE-INDICATORS OF HONEY.

New Zealand Journal of Agriculture, Volume XII, Issue 4, 20 April 1916, Page 279

POLLEN-GRAINS AS SOURCE-INDICATORS OF HONEY.

CONTINUED.

R. WATERS,

Biological Assistant.

The first account of the work under the above head done by the writer appeared in the Journal for September last. A further account, with illustrations and descriptions of some of the more important ellipsoid pollens, was published in the November issue. Reference to these two articles will afford those interested such details concerning the objects of the investigation, the methods employed, and the system of classification as will give a better understanding of the following notes in continuation of the subject.

ELLIPSOID POLLENS.

Type. II (Gorse Type}

Similar to gorse are, — , Broom (Sarothamnus scoparius) figured and described in Journal for November, 1915, p. 387. Apple (Pyrus mains). ..

Apple differs from gorse and broom in its noticeably greater length and breadth. In transmitted light the yellowish-green shade of fresh specimens is readily distinguished from the golden-yellow and very pale watery yellow of fresh broom and gorse respectively. This. pale-yellowish-green shade of apple is similar to that of wild turnip, from which, however, it clearly differs in its greater length and breadth, in its polish due to its capacity for transmitting light, and in its smoothness of surface. The shape of apple is often less regular than that of the other two. Magnified 465 diameters, the surface sculpturing appears as of ■ minute striations, sometimes composed of straight lines, sometimes of curved. Again, the sculpturing may appear as granular. In' these surface characters the appearance of apple differs from the reticulated sculpturing of broom and the still finer one of gorse. Sculpturings are often more clearly shown when the grains have been crushed flat on a glass slide.

Type. IV (Red Clover Type).

Red clover (Trifolium pratense) is a type easily distinguished from types I' (white clover),' II (gorse) and 111 (wild turnip) by reason of its noticeably greater breadth and length. In cubic capacity red clover appears two .or more times greater than gorse, the largest of types I, 11, and 111. Unlike II and 111, the ends of red clover are bluntly rounded—not pointed. Moreover, in proportion to its size, the grooves of red clover are relatively ' notice.ably shallower and narrower than I and 11. Red clover is most

distinct in surface sculpturing, the very coarse and bold reticulation of which alone justified its classification as a separate type of ellipsoid pollen.

Type. V (Escallonia, Type).

Escallonia (Escallonia macrantha), the common dark-foliaged pinkflowered hedge-plant, differs sufficiently in the size and shape of its pollen-grains from previously mentioned types to justify its classification as a separate type. Of the other . types, it resembles type 111 (wild turnip) most, mainly in its colour, which in transmitted light is of slightly paler yellowish-green than the shade common to both type 111. and apple. . It is, however, noticeably broader in proportion to its length than wild turnip, . and its ends are more broadly rounded. Moreover, it is not opaque like type 111, but highly transmissive of light; this character lends . a highly polished appearance to its surface, which , under a magnification of 465 diameters appears also as almost imperceptibly reticulated. Some of the grains of Escallonia approach more or less a spheroidal shape—these are probably immature pollens.