108 



THE (JEOLOfJICAL IIISTonY OF PLANTS. 



i 



I 



!i 



inn I 



I 



ii:- 



.: ii 



Hr 



\-j 



(a) Cnlamites proper, which lias tho woody wo<l(f«>s of soalari- 

 form or Imrred tiH.sii« with Uiin nicduliiiry ruyH, and the thick pri- 

 mary incchillary ruy.s arc c(;ihihir. 



(/i) <'(U(imo])ilHH hiin reticulated or rniilliporouH tJHsiio in tlio 

 woody wedges with medullary rays, and tlic primary mciduilary 

 wed^oH are (;omiK»8(!«l <A clonj;al(;d c(«IIh. 



(c) (Jalainodendrfm has tiie woody wodgcs t)l hjirrcd tissue as in 

 a, with medullary rays, hut iias the interv(!iiirij^ medullary wedt^es 

 of an cU)n^atcd tissue approa<!liing to woody film;, and also with 

 medullary rays. 



To these I would add a fourth type, which I have described, from 

 the coal-formation of Nova S<otia.* 



(d) h'ucdfamodriidron diirers from (Jalamodcndron in having 

 true bordered pores or pseudo-scalariform slit-pored tissue, and cor- 

 responds tr> tho highest tyfw of calamitean stem. 



F would also add that under a and h there are some species in 

 which the woody cylinder is very thin in com[)arison to the size of 

 the stem. In c and d the woody cylinder is thick and massive, and 

 the stems are often large and nodose. 



As an example of an ordinary C'alamite in which the external 

 surface and foliat,'e arc [)reservcd, I iruiy (piotc the following from 

 my report on the " l''l(jra of the Jjower Carboniferous antl Millstone 

 Grit," 1H7:{: 



Calamitks IT.vniiLATUs, Brongniart. — This species is stated by 

 Brongniart to ))e distinguished from Ww ('. Snr.lcovii, the character- 

 istic ('alamite of the middle coal-formation, by its undulated ribs 

 marked with fieculiar cellular reticulation. He suggests that it may 

 be merely a varirdy of 6'. Sur.kovii, an opinion in which Schimper 

 coincides; ])ut since I have received large additif)nal collections from 

 Mr. Elder, containing not only the stems and branches, but also tho 

 leaves and rhizomes, I am constrained to regard it as a distinct 

 thougli closely allied species. 



The rhizomata anf slender, being from one to two inches in 

 diameter, and jierftfctly flattencid. 'i'hey an: beautifully covered with 

 u cellular niticulation on tlu; thin Imrk, and shf)W occasiomil round 

 areoles marking the points of (ixit of the rootlets. I have long Ijeen 

 familiar with irregular flattened st(!ms thus reticulate, ))ut have only 

 recently been able to connect them with this species of C'alamite. 



The nuiin stems present a very thin carlKiiiateous bark reticu- 

 lated like th(! rhizomes. They hav(! flat, broad ribs sej)arated by deep 



*" Quarterly Journal of the Geological Society," 1871. 



