Acta Botanica Neerlandica 7 (1958) 217 —222 On a Megaspore-bearing Lycopod Strobilus S.J. Dijkstra [Geol. Bur., Heerlen) (:received Februiry 11th, 1958) Introduction the last 30 of Carboniferous During years many species megaspores have been described, but until now not much is known with regard to the nature of the fructifications by which they were produced. This be due the fact that all the were may partly to nearly megaspores obtained by macerating lumps of coal, whereas the fructifications are generally derived from the roof of a coal seam. Moreover it is note- that the fructifications contain had worthy rarely megaspores; they shed their before themselves became detached. apparently spores they Some investigators of the past century sometimes found megaspores the in the strobili they were studying, but not realizing importance their small of findings, they unfortunately figured them on a very that it is scale. Their descriptions too are insufficient, so now very of these difficult or impossible to establish the identity spores. number of have However, during recent years a investigators paid attention to the fructifications well to the that are included as as spores in them. The most important communications on this subject are: Arnold (1930), Lepidostrobus (?), (1933, ’35), Lepidostrobus or Sigil- lariostrobus, (1938), Lepidostrobus (Lepidocarponi?), (1949), Lepidostrobus; Bochenski (1936) Lepidostrobus (Lepidocarpon!?), (1939), Sigillariostrobus; Ghaloner (1952), Lepidocarpon, (1953a) Lepidostrobus (?), (1953b), Lepidostrobus, (1953c), Sigillariostrobus, (1954), Selaginellites, Lepidostrobus (Lepidocarpon), (1956), Sporangiostrobus; Felix (1954), Lepidostrobus, Lepidocarpon; Hoskins and Cross (1940, ’52), Lepidostrobus; Leqlerq, Mathew (1938), Sigillariostrobus (Lepidostrobusr?) ; (1940), Lepidostrobus', Nemejg (1931), Sigillariostrobus (?); Schopf (1938), Lepidocarpon; Wicker Porostrobus. A detailed of the American (1934), very survey literature can be found in Felix (1954). From the that the identification of list given above, it appears several of the fructifications is regarded as doubtful, and this probably of the applies also to some the other ones. This is the reason why of the different of to the various assignment species megaspores often remains The have strobilus genera uncertain. same difficulty we other experienced with the fossils described in this paper. It is, on the rule difficult refer the isolated from hand, as a not to megaspores such strobili the to right spore genus. Description Sigillariostrobus cf. major (Germar) Zeiller. PI. I, Fig. 1; PI. 11, Figs. 4,5; PI. 111, Fig. 11; PI. IV, Fig. 12. 217 218 S. J. DIJKSTRA Cone cylindrical, at least 9 cm long, 3-4 cm in diameter including the sporophylls. Stalk of the cone unknown. Sporophylls placed in slowly ascending spirals; adaxial part horizontal, rhomboidal, sides 6 5 sterile bent slightly concave, mm wide, mm high; part spreading, towards the of the with the linear, apex cone, tips nearly vertical, ciliate. Axis 4 in 2.8 mm wide, 17 mm long; margin not mm diam.; from left to right 3-4 leafscars are distinguishable, placed in a spiral which includes an angle of about 27° with the horizon. Distance in horizontal direction 0.6 distance of the vertical of the scars mm, The thumb-nick of the series 2.5 mm. scar resembles the a knife, curvature of which is turned towards the base; it is about 0.5 mm high, 0.7 mm wide. The elliptical sporangia are radially elongated, 2 mm high, 3 mm long. Fully developed megaspores. PI. I, Figs. 2, 3; PI. II, Figs. 6, 7, 8, 10. with neck-like Body of the spore oval-rounded, provided a pro- of the 600-810 702 minence; length body spore /,< (the mean being 10 whole 79Ö- spec, meas.), length spore (the prominence included) 1020 909 diameter of the 610-750 //, (the mean being fi), body spore /x (the mean being 684 (i). Prominence cylindrical-pyramidal, top 240-290 250-310 wide. Triradiate rounded, fx long, fi ridges clearly 30 wide and distinguishable, running from tip to arcuate ridges, // 350-570 Arcuate 30-50 high; distance tip to arcuate ridge fx. ridges /x 10-15 the faces by an wide, [x high. Wall, contact included, rough translucent 5-8 irregularly spread of hemispherical, red bodies, /t in diameter. Wall 20-25 thick. fx 630 PL 9. Not-fully developed specimens are /< long; II, Fig. Occurrence, discussion and comparison informed these strobili found him As Prof. Jongmans me, were by Mr. M. K. time connected with and Ellias. They were at that Sigil- laria brardii, but the discoverers have tried in vain to make a photo- graph of them in situ. When I found them in the collection of the Geol. Bureau at Heerlcn they comprised 8 pieces (parts and counter parts), enclosed in a clayey shale which moreover contains a great brardii number of grass-like leaves; the rests of Sigillaria have been 4 miles lost. They were collected at locality 54, Lawrence Shales, W. of the of which is Tonganoxio, Ka, age Stephanian. fructifications is The axis is The preservation of these very good. partly covered with the imbricate fertile parts of the sporophylls (PI. IV, Fig. 12), and partly naked, so that a number of sporophyll- both sides of the scars are clearly distinguishable (PI. II, Fig. 4). On visible The of the axis complete sporophylls are (PL I, Fig. 1). apex fructification too is represented (pi. II, Fig. 5). A single megaspo- rangium can be seen (PI. II, Fig. 4, indicated by the two arrows); another is covered with number of cone, more decayed, a great The could be removed megaspores (PI. Ill, Fig. 11). spores easily treated for hours by means of a needle, and after they had been some S. J. DIJKSTRA: On a Megaspore-bearing Lycopod Slrobilus PLATE I 1. Fig. Sigillariostrobus cf. major (Germar) Zeiller; 3 X, photo No. 12274. 3. Isolated 50 Figs. 2, megaspores; X, photo No. 5292. PLATE II 4 shows Figs. 4, 5. Sigillariostrobus cf. major (Germar) Zeillcr; Fig. a megasporan- gium (indicated by the two arrows); 3 X, photo No. 12275. 6-10. 50 No. 5292. Figs. Isolated megasporcs; X, photo PLATE J11 11. Fig. Sigillariostrobus cf. major a number of (Gcrmar) Zcillcr; great megasporcs is G distinguishable; x, photo No. 12276. PLATE IV Fig. 12. Sigillarioslrnbus cf. major (Germar) Zeiller; 3 X, photo No. 12271. Photographs by L. R. Funcken ON A MEGASPORE-BEARING LYCOPOD STROBILUS 219 with a 30 % fluoric acid solution, they proved to be sufficiently cleaned (PL I, Figs. 2, 3; pi. II, Figs. 6-10). Microspores have not been found. These to the sectio megaspores belong Lagenicula. In the literature two Sigillariostrobi are known, to produce mega- spores belonging to the sectio Lagenicula. They are: Sigillariostrobus major Germar and Sigillariostrobus spectabilis Renault. The former was described by Zeiller (1906), and compared by him with Sigillodendron frondosum (Goeppert) Weiss and Lepidodendron frondosum, Goeppert and with Volkmannia major (Germar), but accor- ding to Jongmans (1932) the specimen of Goeppert is a doubtful rest, The and the same can be said of Germar’s specimen. specimen de- scribed Zeiller has of 21 and diameter of 3 the by a length cm, a cm, included. The of the is similar sporophylls curvature sporophyll very to that observed in our specimens; its sterile part must be about 1.5 cm long, and about 3 mm wide. It is a pity that Zeiller himself gave but few details with regard to the dimensions of the sporophylls. The from this fructification the sectio megaspores typically belong to Lagenicula. The diameter of fully developed specimens is 1-1.5 mm, their wall is smooth; not-fully developed specimens vary from 0.8 1.0 to mm. The description and the figures of Zeiller’s spores are too imperfect for a satisfactory comparison with ours. According to Zeiller that is the fructification of it is very probable Sigillariostrobus major Sigillaria brardii. Sigillariostrobus spectabilis Renault (1888) is the other known species that bore This strobilus is 10.5 lageniculate megaspores. cm long, 3 cm in diameter, and on the 4-5 mm wide axis the leaf-scars are placed in an irregular verticil. The adaxial part of the sporophyll is isosceles attached its The base of the an triangule, by top. triangle 5.5 the of the sterile of the is measures mm; length part sporophyll The wall of the which 0.8 in diameter 35 mm. megaspores are mm is minutely granulate. Other specimens belonging, according to found leaves and Renault (1888), to the same species, were among branches of Sigillaria brardii. Zeiller (1906) figured and discussed the he the of the same species; rightly recognized nature megaspores. In comparison with our specimens S. spectabilis has a larger diameter, the spreading sporophylls included it is 6 cm in diameter; the sterile of the is and about 5.5 and part sporophylls longer wider, mm, they than The are more spreaded they are in our specimens. description of the satis- and the figures megaspores are too incomplete to allow a with factory comparison our spores. There is still another strobilus, namely S. strictus Zeiller which, be according to Zeiller (1884), might a fructification of Sigillaria this strobilus brardii, and of too megaspores are known. However, they belong to the sectio Aphanozonati. It is not probable that S. brardii, have although a very variable “species”, may produced megaspores different belonging to megaspore genera. from Finally we can compare the megaspores our fructifications with with isolated resemble “sporomorphae dispersae”, spores. They T. brasiliensis Dijkstra (1955b), but in this species the length of fully 220 S. J. DIJKSTRA varies from about 1180 to 1160 their radiate developed specimens fi /u, their neck-like is ridges are more robust, prominence more pyramidal than cylindric, and the hemispherical bodies on the wall are generally larger.