204 



BOTANICAL GAZETTE [September 



In 1896 Worsdell (16) discovered them in the adult stem of 

 Macrozamia Fraseri Miq., giving it an appearance which recalled to 

 his mind the stem of the Medullosae. 



In 1897 the same author (17) gave the name "transfusion tissue" 

 to certain short, scattered tracheids with reticulate markings on 

 their transverse walls, found in lateral communication with the 

 bundles in the green parts of some gymnosperms. He considers this 

 tissue a "direct derivative of the centripetal xylem" in the vascular 

 bundles of fossils. Later in the same year (18) he recorded its 

 occurrence in the cotyledons of Cycas revoluta Thunb. and in the 

 leaf traces of Stangeria paradoxa T. Moore. He found that in each 

 of the two cotyledons of Cycas revoluta, there are three collateral 

 bundles, which may increase to five; that there may be some cen- 

 trifugal wood near the base of the cotyledon, but none farther out; 

 that the root may be tetrarch or triarch; that girdling had not yet 

 begun in the young seedling he was investigating; and that anomalous 

 thickenings were conspicuous. In Stangeria paradoxa, the two coty- 

 ledons have a common stalk, each is multifascicular, and the bundles 

 are said to be concentric near the base. The root is triarch, changing 

 to diarch near the tip. In the same paper, the two cotyledons of 

 Macrozamia spiralis Miq. are said to be like those of Cycas revoluta. 



The author calls attention to the absence of anomalous thicken- 

 ings in this species of Macrozamia in contrast with the mature stem 

 of M. Fraseri previously studied by him. In all three seedlings 

 Worsdell missed the transition from stem to root. 



In 1898 the seedling of Bowenia spectabilis Hook, was described 

 by Pearson (9). He says that each of the two cotyledons has four 

 to seven bundles derived from one, and that these bundles are all 

 collateral with normal orientation. He is emphatic as to the collateral 

 nature of the bundles, even after having examined a preparation of 

 Worsdell's in which the latter considered them concentric. In 

 the leaves the bundles are oriented normally, and the centripetal 

 wood, scanty at the base, becomes more and more abundant farther 

 up the petiole; but the centrifugal wood does not disappear even in 

 the pinnae. The root is tetrach or pentarch, but may reduce to triarch. 

 In the young material at his disposal, Pearson found no anomalous 

 thickenings in the root, but they were discovered later in presumably 



