370 Fritsch, Observations on the young plants of Stigeoclonium Kütz. 
species of Alga is described, inhabiting Lemna gibba both epiphyti- 
cally and endophytically, and, especially under the latter conditions, 
presenting many points of resemblance to the genus Endoclonium, 
established by Szymanski in 1878 (cp. Szymanski 78, p. 18). 
However Huber shows that „malgre les analogies nombreuses avec 
le genre Endoclomum, cette algue endophyte et Epiphyte du Zemna 
gebba peut, A l’etat adulte, rentrer tout aussi bien dans les nom- 
breuses varietes du Stiyeoclonium tenue Rabenh. (p. 277).“ It is 
in fact a Stigeoclonium. At another point in the same paper Huber 
remarks: „, . les resultats de mes recherches. .. tendent & demontrer 
que les genres Stigeoclonium et Endoclonium different encore moins 
qu’on ne le croyait jusqu’ici, qui y a m&me quelque difficulte & 
trouver des caracteres distinctifs entre les deux genres.“ Later 
Klebs (96, p. 399, foot-note) advocates the inclusion of the genus 
Endoclonium in Stigeoclonıum, as Hansgirg (86, p. 68) had done 
ten years previously.'!) 
Finally I may already mention here that Berthold in the 
paper above referred to (78, p. 201) describes a species (Stig. 
faretum Berth.), which is curious in the extent to which branching 
takes place in the basal portion. „Die Keimung erfolgt wie bei 
St. lubricum?), die junge Sohle verzweigt sich aber von Anfang an 
sehr reichlich, aus einer Zelle entstehen häufig drei, sogar vier 
Zweige, so dass von Anfang an eine pseudoparenchymatische Scheibe 
angelest wird (Tafel 2, Figur 1, 5, 3, 2), deren Zellen dann sehr 
schön in radial verlaufenden Reihen angeordnet sind.“ — Möbius 
(88, p. 239) describes a similar form from Porto Rico, growing on 
leaves of Potamogeton occidentalıs. 
The object of these introductory remarks has been to show 
the considerable variety existing in the outward appearance of the 
early stages in the development of a Stige:clonium. "The young 
plants usually (not invariably though, as will be shown below), have 
a creeping basal portion, but this may vary very much in the extent 
of its development and nm a few remarkable cases is sometimes 
endophytic. 
The results, embodied in the present paper, are in part merely 
confirmatory of earlier observations. For my investigations I chiefly 
employed three species of Stigeoclonium, all of which were obtained 
from the artificial waters of the Royal Botanic Gardens at Kew. 
These species were purposely chosen as distinet from one another 
as possible, and althoush the genus Stigeoelonium undoubtedly in- 
cludes many bad species, these three are deserving of specific 
separation.e The three were, as far as could be determined, ‚Stig. 
variabile Näg., Stig. nanum (Dillw.) Kütz. and a form closely 
resembling Stig. faretum Berth.°). 
1) Hansgirg (loc. eit.) places Endoclonium as a second section of the 
genus, the first section being Zustigeoclonium and including all the forms up 
till then described as Stigeoclonium. In the second section Hansgirg places 
a single species, Sf. pygmaeum Hansg., which he later (95, p. 217) unites 
with St, farctum Berth. as var. pygmaeum Hansg. 
2) that is according to Berthold’s second type. 
3) Of these three species the first had rather narrow, rectangular cells 
whose length generally considerably exceeded the diameter; branching was 
not very abundant, many of the branches terminated in a hair with a blunt 
