ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
819 
regular rectangle ( Tradescantia, Commelyna , Pothos , Calandrinia ), or less 
regular ( Arum, Pichardia , Vanilla , &c.) ; b , the contraction affects the 
guard-cells chiefly from the sides, 2 border-cells ( Armeria , Claytonia , 
many Monocotyledons) ; II. Coriaceous-succulent type ; a, 2 or 3 
border-cells surround the stomate (Asclepiadeae, Rhizophoracese, &c.) ; 
6, 2 border-cells on one side of the stomate ( Maranta , JuncacesB, 
Gramineae, Cyperacese). Many forms are of an intermediate character ; 
thus Mesembryanthemum and the Juncaceae and Glumiflorse might almost 
as well be placed under B I b. 
Capitate Hairs and Motile Filaments of Dipsacus.* — Prof. R. 
Chodat and M. R. Zollikofer have investigated the nature of the 
trichomes found in the cup formed by the union of the bases of the 
opposite leaves of Dipsacus sylvestris and other species of the order, 
which they state to be totally different from those of Lathrsea. They 
have been considered variously as threads of protoplasm, rods of wax, 
and bacteria. The authors have determined that they present none of 
the reactions of protoplasm ; and they believe them to be simply excre- 
tory products endowed with remarkable powers of vibratory motion 
closely resembling those of animals. The interior of the cup is 
furnished with a large number of multicellular capitate hairs. At the 
summit of each of these hairs is one of the bodies in question, which 
may assume the form either of a button — usually sessile, less often 
stalked — of a hollow vesicle, or of several longer or shorter threads of 
great tenuity which display this remarkable power of motion, and 
possess the faculty of retraction. 
Fastigiate Hairs of Potentilla.j — Dr. A. Waisbecker describes the 
fastigiate hairs which characterize the group Aureae or Stelligeraa of 
Potentilla (P. cinerea, aurea, opaca , arenaria, rubens, tiroliensis, &c.). 
Each consists of an epidermal cell which divides first by a septum 
parallel to the surface, and the lower segment, then by vertical septa 
into 2 or 3 cells which constitute the pedicel; the upper cell then 
divides further into a number of long radiating branches, frequently as 
many as from 10 to 20. These are often combined with another form 
known as “ comb-hairs.” 
/3. Physiology. 
Cl) Reproduction and Embryology. 
Staining-reactions of the Constituents of the Nucleus and of the 
Sexual Cells of Plants. J — From a series of observations made chiefly 
on Scilla sibirica , Eyacinthus orientalis, and Fritillaria imperialis, Herr 
F. Rosen arrives at the following general conclusions. In the vege- 
tative nucleus two kinds of nucleoles may be distinguished, — the 
ery throphilous or eu-nucleoles, and the cyanophilous or pseudo-nucleoles. 
The latter belong to or replace the chromatic framework of the nucleus. 
The chromatic framework and its products — the nuclear filament and 
the separating filaments — are cyanophilous ; the eu-nucleoles, the 
* Arch. Sci. Phys. ct Nat., xxviii. (1892) pp. 8P-108 (1 pi.). 
f Oesterr. Bot. Zeitschr., xlii. (1892) pp. 263-5. 
X Beitr. z. Biol. d. Pflanzen (Cohn), v. (1892) pp. 443-59 (1 pi.). 
