GRAF ZU SOLMS-LAUBACH— MONOGRAPH OF THE ACETABULAIUE.*:. 13 



Notwithstanding' its aberrant external appearance, Ilalicoryne approaches in its 

 structure near to Acetabiilaria^ sect, l^ohjphysa, as Kiitzing j^^stly recognized and expressed 

 in the name he gave it. Its erect stem is clothed in regular sequence a\ ith wliorls closely 

 occurring, alternating, and with different characters ; and, according to the kind of whorl, 

 more or less strongly developed at the nodes. It terminates in a cupola or dome-shaped 

 growing-point, surrounded by tlie young bud-like whorls, which are inclined towards it ; 

 or, when its growth in length has ceased, quite abruptly, with a flat surface immediately 

 above the last fertile whorl. The whorls consist in one case of repeatedly multisect hair- 

 tufts of the usual kind, developed as a rule in groups of eight, but very soon falling off 

 and leaving only their round scars on the surface of the stem. These whorls correspond 

 to the less pronounced swellings on the axis. Between these, and, as has been indicated, 

 present only on the full-grown plant, there are 16-branched wliorls of a different kind, 

 arising from the more prominent swellings of the stem. Its branches are completely 

 free, and consist of an almost cylindrical basal portion seated on a small vestibular fold of 

 the stem- tube and divided from it by a basal partition -wall in the well-known fashion, and 

 of a terminal, simple, longish ovate, pointed vesicle curved somewhat upwards and almost 

 pod-shaped — the sporangial ray of the adult fertile plant. On the upper side of the basal 

 portion, in the neighbourhood of the place where it turns into the sporangial ray, there 

 is a minute papilla-like convexity which bears a terminal, short, unicellular hair-process, 

 or two of them, one behind the other. In young branches these hairs are firm and erect, 

 and in the mature ones collapsed ; they remain, however, at least in H. spicata, always 

 persistent, while in the other cases they often, certainly not always, disappear. 



In Salicoryne TFrightii this convexity is always recognizable, even in the mature state, 

 as a small but still definite process ; in H. spicata its elevation is so slight that it barely 

 appears on the mature branches, and the hair-cells rise simply from the surfjxce of the 

 basal portion (comp. Plate IV. figs. 9, 11). We have in it the very feebly developed 

 parts of the corona superior (comp. Plate IV. figs. 4, 5, 10). 



While in AcetahulaiHa the cap-whorl reaches full development first on the older and 

 already strengthened plants, the youngest specimens in this case that I have seen are 

 provided with both sorts of whorls in complete and regular alternation. In such plants, 

 however, there is no spore-formation, which occurs only on the older individuals of about 

 a fingej-'-length. In the young plants of H. spicata, so far as I can perceive, the branches 

 of the sterile fructification- Avhorl are pointed upwards and lie like roof-tiles over each 

 other, much as Kiitzing has figured them ; in those of H. Wrightii (collected by the 

 * Challenger ' Expedition at the Philippines) they sprout forth at right angles from the 

 stem-cell and become recurved and hang down parallel with the stem. So long as the 

 branches of the fertile whorl do not form spores and remain sterile, the basal portion 

 stands in wide open communication with the sporangial ray ; when the spores are formed 

 a partition is developed which is characterized by strong and often very irregular thickening 

 (Plate IV. figs. 4, 10, 11). Agardh has given a description, correct in the main points, of 

 the structure of Ilalicoryne ; he has recognized the alternation of the different whorls and 

 has seen the coronal prominences on the basal portion of the cap in H. Wrightii, which 

 be only has investigated, although the proportions are not rendered on his plate v. 



