SHASTA ROUTE — SEATTLE TO SAN FRANCISCO. 



45 



or maidenhair treCj so called because its leaves resemble m sbape 

 those of the maidenhair fern. The ginkgo no longer grows wild on 



Oregon give so impressive an air of per- 

 manence and solidity that it seems as 

 if the conditions now found there muet 

 have been unchanged from the beginning 

 of time, yet we have but to turn to the 

 study of the vegetation entombed in the 

 wayside rocks to prove conclusively that 

 during Jurassic time the land was clothed 

 with a flora totally unlike that which now 

 covers it. In the Jurassic period, whose 

 antiquity can be measured only in mil- 

 lions of years, the dominant types of 

 vegetation were ferns and cycads, which 

 were accompanied by smaller numbers of 

 conifers, horsetails, and the curious 

 ginkgo. The types dominant in the flora 

 of to-day are the monocotyledons (grasses, 

 sedges, lilies, palms, etc.) and the still 

 more abundant dicotyledons (oaks, elms, 

 maples, etc.), but so far as we know no 

 plants belonging to either of these great 



iated in Jurassic time. 



groups 



A few miles southwest of Riddle there 

 has been found a flora of about 70 species, 

 making this one of the richest localities in 

 the world for plants of Jurassic age. Of 

 these species about 20 are ferns, 30 are 

 cycads, and 10 are conifers, and the 

 remainder belong to a number of more or 

 leas doubtful groups. 



The largest number of ferns belong to 

 the extinct genus Cladophlebie, mainly 

 rather small ferns with much-divided 

 fronds. Another wholly extinct form is 

 Tsenioptoris, which has long, narrow 

 fronds similar in type to the grass fern, 

 now found in this country only in Rorida. 

 Adiantites is believed to be one of the an- 

 cestors of the maidenhair ferns, of which 

 there are many living species. There 

 are also three that are thought to belong 

 to living genera — Dicksonia, which is not 

 now found in this country; Polypodium, 

 which is now a very large, mainly tropical 

 group, though a few email species are 

 found in temperate lands; and Th>Tsop- 

 teris, a fern with finely divided fronds, 

 the only living representative of which is 

 a species in the island of Juan Fernandez, 



The cycads were not only the most 

 abundant as regards different kinds but 

 in individuals as well, some collections 



containing literally hundreds of speci- 

 mens. They all belong to extinct typ^, 

 and many of them were evidently large 



ms 



sibly with trunks, at the top of which grew 

 large compound leaves disposed in a 



circle or crown. 



One of the most abundant and con- 

 spicuous plants of this flora was the ginkgo, 

 of which four or five species have been 

 found here. The ginkgo is now repre- 

 sented by a single species in China and 

 Japan, where it is a more or less sacred 

 tree, found about the temples. It is not 

 certainly known to exist in a trul}- ^vild 

 state anywhere. This tree has had per- 

 haps a more wonderful history than any 

 other now living. It appeared at least as 

 early as the close of the great Paleozoic 

 era, and by or even before the Mesozoic 



FiGUEE 8.— Sketch of a gin 



JtiTLissic beds of C 



mi 



over most of the world except the ex- 

 treme southern hemisphere. It has come 

 down to us so little changed that some of 

 +>iA IpavpR from the Jm^ssic rocks of Ore- 



character 



.guiehed 



of the li\-ing tree. (See fig. 8.) Had it 

 not been for the fostering care of man the 

 genus would apparently have become 

 extinct several centuries ago. - 



Associated ^vith the ginkgo leaves in 

 many of the Jurassic deposits of Oregon 

 are a few branchlets of strange conifers, 

 such as Sphenolepidium, Pagiophyllum, 

 and BrachyphyUum; also a few forms 

 that are referred with more or less un- 

 certainty to living genera, such as Pinus 

 (pine), Sequoia (redwood), Araucana, 

 and Taxites (yew). 



