HARDWICKE'S SCIENCE-GOSSIP. 



77 



covered with the Trientalis and where every day 

 during the season you may find countless specimens 

 gracing woodland and moor with lovely white 

 flowers. 



The stem of the plant as it is usually found, is 

 simple and bears a few small scale leaves on its lower 



Fig. 34-— Chickweed winter green {Trientalis Europ&a). 



portion, while the upper part of the axis which bears 

 the ordinary foliage leaves is shortened so as to present 

 them as if in one whorl. Here the axis ends with a 

 bud which most commonly does not develop, and the 

 leaves are therefore displayed in a terminal whorl-like 

 arrangement. The number of the leaves varies from 

 about four to nine ; but from five to seven will be 



found on by far the greater number of plants. In 

 shape the leaves vary from obovate to lanceolate, and 

 they always taper more or less to a stalk and have their 

 broadest part towards the apex. This, of course, is a 

 mechanical necessity for leaves that are arranged in a 

 rosette-like fashion ; they must be narrowed at the 

 common axis, where there is no room for expansion, 

 while their blades may assume a sufficient area for 

 nutritive purposes towards the circumference of the 

 system. On luxuriantly growing plants the largest 

 leaves exceed three inches in length, but the usual 

 size is less than this. 



The flowers arise in the axils of the leaves, and 

 are borne on long stalks which raise them up and 

 show them to good advantage over the green foliage. 

 Among British plants the flower is unique in having 

 most commonly seven petals and seven stamens, and 

 for this reason it stood alone in Britain among the 

 Heptandria of Linnaeus. But it must not be supposed 

 that it goes nearly always by sevens, for you may find 

 any number from five to nine, seven always pre- 

 dominating. Of a hundred specimens once counted 

 at random at a particular spot we found nine with 

 five petals, twenty-two with six, forty-three with 

 seven, twenty with eight, and six with nine. This, 

 however, cannot be taken as decisive of more than 

 the fact, that there may be many flowers found which 

 are not heptamerous. At other spots you might get 

 the numbers to vary considerably from the above ; we 

 have at some places failed to get any with nine petals 

 and observed that few had eight. In all cases the 

 development of the flower decides that there must be 

 the same number of stamens as petals, and we may 

 consequently find any number of stamens from five to 

 nine. 



The Trientalis belongs to the Primulaceoe, and 

 resembles the pimpernel with its rotate corolla and 

 the arrangement of its stamens, but it necessarily 

 differs from the whole order whose flowers are usually 

 pentamerous, while those of the Trientalis are but 

 rarely so. Our plant is the only species recorded in 

 Europe, and there is but one, the T. Americana, on 

 the other side of the Atlantic. Some botanists take 

 the two to be the same, so that the only difference may 

 be a geographical one. Dr. Hooker gives the dis- 

 tribution of our species as "north of the Alps and 

 Italy, Siberia to Kamtschalka," and this goes to show 

 that it is a lover of northern latitudes. 



Besides the usual plant there is another form of 

 which no notice seems to have been taken in books, 

 but which ought not to be overlooked, as occurring 

 frequently in certain localities in Scotland. This is 

 the case where the axis is prolonged beyond the usual 

 whorl of leaves, and a second whorl-like system of 

 smaller leaves developed at a higher level. From 

 the axis of one or more leaves, in either or both 

 whorls, flowers may arise, but as the development is 

 acropetal, the lower flowers are usually fading before 

 the higher ones have opened. The fact that large 



