Miscellanea. 311 



but originating heloiv the joints and external to the sheaths. This 

 is not the case with the fossil before us, in which the branches 

 originate directly over the joints, and are therefore within and 

 axillary to the sheaths, which may thus, with their appendages, be 

 considered as true leaves, and having the same relation to the 

 branches as in ordinary plants. Iliis character is of such import- 

 ance, that the resemblance of Phyllotheca to Equisetum is proved 

 by it to be of the most trifling nature, and that there can be no real 

 affinity between them. On the other hand, when compared with 

 Casuarina, the affinity seems to me to be exceedingly strong, 

 although botanists have not, I believe, hitherto so considered it. 

 The Casuarince are exogenous weeping trees, with slender cylin- 

 drical branches ; their shoots regularly jointed, longitudinally sul- 

 cated, and surrounded at the joints with toothed sheaths as in 

 Equisetum ; while the branches originate either in a verticillate or 

 irregular manner immediately above the joints and within the 

 sheaths, showing a perfect agreement with the above-mentioned 

 PltyUotheca. But a still more interesting and important proof of 

 the relation of those plants to Casuarina, and removing them still 

 farther from Equisetum., is to be found in their mode of inflorescence, 

 of which I have fortunately noticed a fragment among the speci- 

 mens at my disposal. The specimen alluded to is a portion of a 

 branch (see PI. ^^T- fig- 1) with the joints more approximate than 

 on other parts of the plant, their length being scarcelj equal to 

 their diameter; the sheaths are the exact length of the internodes, 

 and fringed on their upper margin with a dense little whorl of 

 (I think two-celled) anthers, agreeing very closely with the male 

 flowers of Casuarina stricta and allied species, with which (bemg- 

 in flower at this time in the houses of the Cambridge Botanic 

 Garden) I have been enabled to compare it as advantageously as 

 the state of preservation of the fossil would allow. The fructifica- 

 tion of Equisetum is entirely different, forming a dilated, club-shaped 

 mass at the end of the branches or at the extremity of a particular 

 stem. The PhyUothecaaustralis is described as having the sheaths 

 closely applied'to the stem, the leafy appendages tuice the length 

 of the sheaths, without midribs, and having the naked portion of 

 the stem between the sheaths smooth. Of the two species which 

 I have seen tliis would best agree with the branched one, which 

 however has a midrib, although not a very prominent one. The 

 species which agrees with the definition in being simple-stemmed, 

 diff"ers in having the sheaths very loose or infundibuliform, and so 

 long as to extend the entire way from one joint to the next, so as 

 to leave no bare space of the stem visible ; the leaves are very long 

 and have a strong prominent midrib, and the stem when deprived 

 of the sheaths is seen to be always coarsely sulcated. Under these 

 circumstances the obvious course seems to be to modify the defini- 

 tion of the genus so as to include the two species under consideration, 

 and to characterize them as distinct species. If the supposed affinity 

 with Equisetum were borne out, I should probably have considered 

 the loose-sheathed, simple-stemmed plant as the fertile shoot, and 

 the branched stems with small tight sheaths as the barren shoots, 

 following the analogy of some of our best-known recent species of 

 Equisetum ; but having seen that they are constructed in an essen- 

 tially diff'erent manner, we cannot do better tlian as 1 have proposed. 



