136 HOUSE, GARDEN, AND FIELD 



springing up in the most unexpected places. No doubt 

 this species is often unconsciously introduced by man, the 

 seeds having been shot into manure-heaps, or pots of 

 earth, and then removed in the course of trade. 



Wood sorrel produces, as is well known, two kinds of 

 flowers, one of which is small, appears late in the season, 

 and never opens, so that it is necessarily self-pollinated. 

 In these small " cleistogamous " flowers the stamens are 

 short, and the anthers lie close to the stigmas. Pollen- 

 tubes are emitted from pollen-grains which have never 

 left the anthers. The stalks of the cleistogamous flowers 

 are short and bent downwards, so that they are often 

 hidden in moss, or sunk a little in the ground. As in some 

 violets, the cleistogamous flowers are often buried beneath 

 fallen leaves and a sprinkling of loose soil ; in the far north 

 they must be regularly covered with snow. Long after 

 the seeds of the aerial fruits have shot off, the subterranean 

 fruits go on ripening. 



The first printed account of the sudden discharge of the 

 seeds of a wood sorrel is to be found in the description of 

 the yellow wood sorrel by John Jacob Dillen, a learned 

 German botanist, who, writing in Latin, called himself 

 Dillenius. He was brought to Oxford in 1721 by our own 

 botanist, William Sherard, formerly consul at Smyrna, 

 and was by Sherard's will appointed the first professor 

 of botany in Oxford. In 1732 Dillenius published 

 a great work in two folio volumes, illustrated by many 

 fine plates engraved by his own hand, and named the 

 Hortus Elthamensis, because it described the exotic plants 

 cultivated in Dr. James Sherard's gardens at Eltham. In 

 this work Dillenius figures the yellow wood sorrel, for 

 which, in those pre-Linnaean days, he had no more con- 

 venient name than " Oxys lutea, Americana, humilior et 

 annua." He notes that the leaves fold up at evening or 

 during rain. The flower-stalks, he goes on, at first droop, 

 but erect themselves when the flowers expand ; after 

 flowering is over, they bend down again. The capsule is 



