148 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Verticillate Ramification.* * * § — M. P. van Tieghem points onfc a devia- 
tion in certain Algae from the ordinary mode of verticillate ramification, 
where homologous elements are superposed at each node. The excep- 
tional mode has been observed only in certain Algae belonging to the 
Florideae ( Ptilota , Euptilota, Pterota, Bonnemaisonia'), and consists in 
the superposition of homologous elements only in pairs. 
Agardh’s Analecta Algologica.| — In “ Continuatio III.” of this work 
Prof. A. G. Agardh establishes four new genera of Algae, viz. : — Homceo- 
stroma, founded on Punctaria latifolia ; Endarachne, near to Phyllitis ; 
Hooperia , founded on Chylocladia Baileyana; and Diplocystis ( Agardhinula 
De Toni), on Callophyllis Brownese. The trichosporanges of Dictyota 
crenata , the cystocarps of Cordylecladia furcellata, and the antherids of 
Sarcomenia dasyoides , are described. The genus Cystoseira is divided 
into three subgenera, — Bapidophora, Thcsiophyllum , and Eucystoseira ; 
and Liagora into two, — Euliagora and Goralict. 
Procarp and Cystocarp of Ptilota.j — Mr. B. M. Davis describes in 
detail the structure and development of the procarp and cystocarp in 
this genus of Florideae, especially in two American species, P. serrata 
and plumosa. The structure and development of these organs agree in 
general features with those of allied genera, e.g. Callitliamnium , Ceramium , 
&c., but differ in some interesting points ; and the author considers there 
is strong evidence that the ordinary mode of reproduction of Ptilota is 
non-sexual or apogamous. In no case were any pollinoids found 
attached to the trichogyne. The procarp consists of a trichogyne, a 
carpogenous cell, and an intermediate portion composed of one or two 
cells, the trichoplioric apparatus. The distance between the trichogyne 
and the carpogenous cell is so great that it is difficult to conceive of the 
sexual fusion being transmitted from one to the other without the inter- 
vention of an ooblastema-filament ; and no trace can be detected of a 
structure of this character. In P. serrata the cystocarp is always 
developed from a single carpogenous cell ; in P. plumosa from one of 
two cells, 
Thorea.§ — Herr F. P. R. v. Wellheim describes several points in the 
structure of Thorea ramosissima, especially the gelatinous sheath which 
envelops both the medullary filaments and the basal cells as well as the 
monosporangial filaments. The sheaths of the separate filaments are 
seldom to be clearly distinguished, and have then usually only a single 
septation ; more often they are more or less confluent. 
Pilinia and Stigeoclonium.|j — Miss Josephine E. Tilden has cultivated 
the rare alga Pilinia diluta, and finds it to be a stage in the development 
of Stigeoclonium flagelliferum or some nearly allied species, which also has 
a CfisetopJiora-form ( C . pellicula) and a Palmella- form. The Pilinia stage 
is characterised by a calcareous secretion; bristles are formed under 
cultivation. In Pilinia the authoress observed conjugation between 
microzcogametes, resulting in the production of a planozygote. In 
* Ann. Sci. Nat. (Bob), ii. (1S96) pp. 350-71. 
f Acta R. Soc. Phys. Lund, xxxii. (1896) 140 pp. and 1 pi. 
X Bot. Gazette, xxii. (1896) pp. 353-78 (2 pis.). 
§ Oesterr. Bot. Zeitschr., xlvi. (1896) pp. 315-20 (1 pi.). 
I! Minnesota Bot. Studies, 1896, pp. 601-35 (5 pis.). 
