114 Anatomie. — Morphologie, Befruchtung, etc. 



of (only) such distinctions. It would be necessary to examine the 

 internal structure in order to make the comparison so complete as 

 possible. But so far only the european Isopyrum thalictroides has 

 been examined anatomically, and the writer describes now in the 

 present paper the anatomy of the american /. hüernatian, from 

 which the following points may be mentioned. The secondary roots 

 Vary from slender in their entire length to moniliform; in the tube- 

 rous portions of the latter the increase in thickness is mainly due 

 to the large development of the secondary cortex, while the stele 

 shows yet the primitive diarch structure with only two additional 

 rays of secondary hadrome with two Strands of secondary leptome, 

 This small increase of the stele is, also, to be observed in the 

 slender roots. 



The subterranean stem-portion is slender and of a rather weak 

 structure; the cortex is more or less collapsed; there is no endoder- 

 mis, but a sheath of collenchyma, sometimes intermixed with tj'pical 

 stereome, surrounds the stele. We find in the stele fine collateral 

 mestome-strands with interfascicular cambium surrounding a central, 

 thinwalled pith. A similar structure was observed in the stem above 

 ground. Characteristic of the long petioles is the lack of mechanical 

 tissue and the absence of an endodermis; there are six mestome- 

 strands arranged in a circular band surrounding a partly hoUow 

 pith, thus petiole and stem show principally the same structure in 

 regard to the mestome-strands. In the leaf-blade the structure is 

 bifacial, and the stomata, which are surrounded by four to five 

 ordinary epidermis cells, are confined to the dorsal face. The veins 

 have thinwalled parenchyma-sheaths, and the larger of these have, 

 furthermore, a small support of hypodermal collenchyma. 



By comparing the anatomy of /. biternatiim {Enernion) with that 

 of /. thalictroides {Euisopyrum) the following distinctions were noti- 

 ced. /. thalictroides possesses in the stem above ground an endo- 

 dermis and ajpericycle of two zones, an outer very heavily sclerified, 

 and an inner more thinwalled; in the leaves the chlorochyma is 

 almost homogeneous according to the investigation of Marie. 



It would be interesting to know the structure of all the species 

 of the genus, not only the internal, but also a little more about the 

 external, for instance of the rhizomes, which so far have not been 

 described very carefully; there it might be possible to decide whe- 

 ther the genus Isopyriint shall be maintained as a Single genus or 

 divided into Enemion, Leptopyrum cet. Theo Holm. 



Binford, R., The development of the sporangium of Lxgo- 

 dium. (Bot. Gaz. XLIV. p. 214—224. Sept. 1907.) 



Lygodiuni , a member of the Schiseaceae , presents many features 

 intermediate between Marattiales and Polypodiales , but has a number 

 of special features such as the Single sporangium beneath an indu- 

 sium. The initial cell of the sporangium is marginal, and the early 

 divisions are by means of a wedge shaped (dolabrate) apical cell. 

 Both the sporangium and the spores are large, and the latter num- 

 ber 242 to 258 per sporangium. The conclusion is reached that the 

 Schiseaceae are not on the direct evolutionary line toward Polypo- 

 diaceae. M. A. Chrysler. 



