534 



SCIENCE. 



[Vol. II., No. 37. 



organization can be ascertained from Sterzel's speci- 

 men, it seems to have alternating sterile and fertile 

 bracts, with the sporangia of the latter arranged in 

 fours, as in Calamostachys.' On the other hand, we 

 are now very familiar with the structure of the Cala- 

 mostachys Binneana, the prevalent strobilus in the 

 calcareous nodules found in the lower coal-measures 

 of Lancashire and Yorkshire. It has evidently been 

 a sessile spike, the axial structures of which were 

 triraerous - (rarely tetramerous), having a cellular 

 medulla in its centre. Its appendages were exact 

 multiples of those numbers. Of the plant to which it 

 belonged we know nothing. On the other hand, we 

 have examples supposed to be of the same genus, as 

 C. paniculata 3 and C. polystachya,'' united to stems 

 with asterophyllitean leaves ; but whether or not these 

 fruits have the organization of C. Binneana, we are 

 unable to say. 



We are also acquainted with the structure of the 

 two fruits belonging to tlie genera Bruckmannia ^ and 

 Volkmannia." This latter term has long been very 

 vaguely applied. 



There still remain the genera Stachannularia, 

 Palaeostachya, Macrostachya, Cingularia, Huttonia, 

 and Calamitina, all of which have the phyllomes of 

 their strobili fertile and sterile, arranged in verticils, 

 and some of them display asterophyllitean foliage. 

 But these plants are only known from structureless 

 impressions. That all these curious spore-bearing 

 organisms have close affinities with the large group 

 of the equisetums cannot be regarded as certain; but 

 several of them undoubtedly have peculiarities of 

 structure suggestive of relations with the Calamites. 

 This is especially observable in the longitudinal 

 canals found in the central axis of each type, appar- 

 ently identical with what I have designated the in- 

 ternodal canals of the Calamites." The position and 

 structure of their vascular bundles suggest the same 

 relationship, whilst in many the position of the spo- 

 rangia and sporangiophores is eminently equiseti- 

 form. Renault's Bruckmannia Grand-Euryi and B. 

 Decaisnei, and a strobilus which I described in 1870,^ 

 exhibit these calamitean affinities very distinctly. 



One strobilus which I described in 1880^ must not 

 be overlooked. As is well known, all the living forms 

 of esquisetaceous plants are isosporous. We only 

 discover heterosporous vascular cryptogams amongst 

 the Lycopodiaceae and the Rhizocarpae. My strobi- 

 lus is identical, in every detailed feature of its organ- 

 ization, with the common Calamostachys Binneana, 



1 il. Renault has described a strotilus under the name of An- 

 nularia longifolia, but -which appears to me very distinct from 

 that genus. 



- It is an interestingfact, that transverse sections of the strobili 

 of Lycopodium alpiuum exhibit a similar trimerous arrange- 

 ment, though differing widely in the positions of its sporangia. 



■'' Weiss, Ahhandlungen zur geologischen specialkarte von 

 Preussen und Tbiirinaiscben Staaten, taf. xiii., fig 1. 



* Idem, taf. xvi., iigs. 1, 2. 



s Renault, Annales de sciences naturelles, bot., tome iii., 

 pi. iii. 



" Idem, pi. ii. ' Memoir i. 



8 Memoirs of the literary and philosophical society of Man- 

 cheater, 3d series, vol. iv. p. 248. 



' Memoir xi., pi. liv., figs. 23, 24. 



excepting that it is heterosporous ; having microspores 

 in its upper, and raacrospores in its lower part, — a 

 state of things suggestive of some link between the 

 Equisetinae and the heterosporous Lycopodiaceae. 



Lycopodiaceae. — This branch of ray subject sug- 

 gests memories of a long conflict, which, though it is 

 virtually over, still leaves here and there the ground- 

 swell of a stormy past. At the meeting of the Brit- 

 ish association at Liverpool, in 1870, 1 first announced 

 that a thick, secondary, exogenous growth of vascu- 

 lar tissue existed in the stems of many carboniferous 

 cryptogaraic plants, especially in the calamitean and 

 lepidodendroid forms. But at that time the ideas 

 of M. Brongniart were so entirely in the ascendant, 

 that my notions were rejected by every botanist pres- 

 ent. Though the illustrious French paleontologist 

 knew that such growths existed in Sigillariae and in 

 what he designated Calamodendra, he concluded, that, 

 de facto, such plants could not be cryptogams. Time, 

 however, works wonders. Evidence has gradually 

 accumulated, proving, that, with the conspicuous 

 exception of the ferns, nearly every carboniferous 

 cryptogam was capable of developing such zones of 

 secondary growth. The exceptional position of the 

 ferns still appears to be as true as it was when I first 

 proclaimed their exceptional character at Liverpool. 

 At that time I was under the impression that the 

 secondary wood was only developed in such plants 

 as attained to arboreal dimensions ; but I soon after- 

 wards discovered that it occurred equally in many 

 small plants like Sphenophyllum, Asterophyllites, and 

 other diminutive types. 



After thirteen years of persevering demonstration, 

 these views, at first so strongly opposed, have found 

 almost universal acceptance; nevertheless, there still 

 remain some few who believe them to be erroneous 

 ones. In the later stages of this discussion the 

 botanical relations subsisting between Lepidoden- . 

 dron, Sigillaria, and Stigmaria, have been the chief 

 themes of debate. In this cotmtry we regard the 

 conclusion, that Stigmaria is not only a root, but the 

 root alike of Lepidodendron and Sigillaria, as settled 

 beyond all dispute. Nevertheless, M. Renault and 

 M. Grand-Eury believe that it is frequently a leaf- 

 bearing rhizome, from which aerial stems are sent 

 upwards. I am satisfied that there is not a shadow 

 of foundation for such a belief. The same authors, 

 along with their distinguished countryman the Mar- 

 quis de Saporta, believe with Brongniart that it is 

 possible to separate Sigillaria widely from Lepido- 

 dendron. They leave the latter plant amongst the 

 lycopods, and elevate the former to the rank of a 

 gymnospermous exogen. I have in vain demon- 

 strated the existence of a large series of specimens 

 of the same species of plant, young states of which 

 display all the essential features of structure which 

 they believe to characterize Lepidodendron; whilst, 

 in its progress to maturity, every stage in the devel- 

 opment of the secondary wood, regarded by them 

 as characteristic of a Sigillaria, can be followed step 

 by step.' Nay, more. My cabinet contains speci- 

 mens of young dichotomously branching twigs, on 

 ■ Memoir xi., plates xlvil. -Iii. 



