404 
GINALLOA 
Ginalloa Korth. Loranthaceae (n). 4 sp. Indo-mal. Shrubby 
parasites like Viscum. 
Ginkgo Linn. Ginkgoaceae (formerly placed in Coniferae, and still 
mentioned there in this book). 1 sp. G. biloba L. {Salisburia adian- 
tifolia Sm.), the maidenhair tree, perhaps found wild in Western 
China, but carefully preserved as sacred in temple gardens. It is 
a comparatively hardy tree, growing in the open in Europe, reaching 
100 feet in height, with leaves deciduous in autumn, resembling those 
of the maidenhair fern, and very often with a deep median division. 
The leaves are forked in venation (cf. ferns and cycads). The leaves 
are scattered on long shoots, or crowded at the apex of short shoots, 
which sometimes elongate into long shoots. Below the leaves on the 
short shoot are a few scale leaves. Firs, dioecious, in the axils of the 
uppermost scales or lowest green leaves on a short shoot (so that their 
position differs from that usual in Coniferae with long and short 
shoots). The <? consists of a stalked central axis, bearing scattered 
rather loosely disposed sta., each of which is a slender filament ending 
in an apical scale and two or more pollen-sacs with longitudinal 
opening. The pollen grain forms a rudimentary prothallus of a few 
cells, and the generative nuclei produce two large spirally coiled 
spermatozoids (cf. cycads). The ? flr. has the form of a long stalk 
with two terminal elliptical ovules enclosed at the base by a collar- 
like envelope representing a reduced carpellary leaf. Each ovule 
consists of a nucellus surrounded by one integument, which in the 
ripe seed forms a thick fleshy aril-like covering round a hard woody 
shell. In the mature ovule the greater part of the nucellus tissue is 
reduced to a thin papery layer enclosing a large embryo-sac with 
usually 2 archegonia. Fertilisation occurs before or after the ovule 
has fallen from the tree. The embryo has 2 cotyledons. 
The seed is edible, and yields an oil, and the timber is useful. 
Ginkgo thus represents, or rather is, a very old type, with re- 
lationships to the Cycadeae and the Filicineae. The genus is “in 
all probability a very ancient type, which may have been merged 
into the Cordaitales in the palaeozoic era.” Fossil species of G. are 
found in the Carboniferous, the Permian, the Triassic, and Jurassic. 
Species occur in the Tertiary strata of England. 
For details see Fujii on floral morphology in Bot. Mag. Tokio, 
1895 ; Seward and Gowan in Ann. Bot. 1900, p. 108 ; Ikeno on 
fertilisation in Ann. Sci. Nat ., Bot. xm. 1901, p. 303 ; Lyon on 
embryology in Minn. Bot . Stud. ill. p. 275, and other literature 
referred to in these papers. 
Ginkgoaceae. The only order of Ginkgoales (see p. 124), comprising 
the one very ancient and isolated genus Ginkgo (q.v -) , formerly placed 
in Coniferae. 
Ginkgoales. The 2nd class of Gymnosperms (p. 124). 
Ginora Linn. Lythraceae. 7 sp. Mex., W, Ind. 
