184 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
in order to preserve cultivated lands from the disastrous effects produced 
by the ever-present microbes, whose destruction it is impossible to pre- 
vent, recourse must be had to procedures based on the influence of 
mineral dressings. 
B. CRYPTOGAMIA. 
Classification of Cryptogams.* — In the second edition of his Syl- 
labus der Pflanzenfamilien , Herr A. Engler includes the Peridinieae 
or Dinoflagellatae as a distinct division, divided into three classes, six 
orders, and numerous families. In the primary class of Euphyce^j are 
included the Peridiniese, Baciliariaceae (diatoms), Conjugate, Cliloro- 
phyceae, Characeae, Phaeophyceae, Dictyoteae, and Rhodophyceae. 
Among Gymnosperms, Gingko ( Salisburia ), Wiipidopsis , Baiera, and 
Czenakowskia, are separated from the Taxaceas, and elevated into a 
primary class of the same rank as the Cycadeae and the Coniferae. 
Antherozoids.t — Herr E. Zacharias gives a useful epitome of the re- 
sults of recent investigations on the structure and mode of origin of the 
antherozoids in the higher Crvptogamia and in Gymnosperms. 
Homology of the Blepharoplast.J — Mr. C. J. Chamberlain gives a 
short resume of recent observations on the blepharoplasts in the lower 
plants, identifying with this organ those variously termed by different 
writers Hooker , Kornchen, Korperchen , Nebenkern, attraction sphere, 
directive sphere, centrosome, and centrosome-like body. He thinks 
that the absence of centrosomes from the higher cryptogams and flower- 
ing plants is far from being established. 
Cryptogamia Vascularia. 
Male Prothallium of the Rhizocarpeae (Hydropterides).§ — Herr 
W. Belajeff has investigated the structure and development of the male 
prothallium in the four genera Salvinia, Azolla , Marsilia , and Pilularia , 
with a view specially of determining whether, like all the other Arche- 
goniatae, their antherid has wall-cells. This question he answers in the 
affirmative ; each antherid of Salvinia , Marsilia, and Pilularia , has only 
one such cell, while that of Azolla has two. The structure of the male 
prothallium exhibits striking resemblances in the four genera. In all 
of them it breaks up in the first place into three superposed cells or 
segments. Owing to the position and direction of the first septa, the 
young prothallium is always dorsiventral. From the lower segment 
of the male prothallium there is, in all cases, a small lenticular cell cut 
off. From the middle segment, in Marsilia, Pilularia, and Azolla, first 
one, and then a second sterile cell is cut off; the remaining section 
of the middle segment forms the wall-cell or stigmatic cell of the 
antherid, and the mother-cell of the spermatogenous mass. In the 
antherid of Marsilia and Pilularia , the wall-cell undergoes no further 
division ; in Azolla it divides into two cells. In Marsilia and Pilularia, 
the mother-cell of the spermatogenous mass first divides by a wall 
which coincides with the plane of symmetry of the prothallium, then 
* Syllabus d. Pflanzenfamilien, 2 te Ausgabe, Berlin, 1898, 214 pp. See Bull. Bot. 
Soc. France, xlv. (1898) p. 318. t Bot. Ztg., lvii. (1899) 2 te ALth., pp. 1-6. 
X Bot. Gazette, xxvi. (1898) pp. 431-5. 
§ Bot. Ztg., lvi, (1898) pp. 141-94 (2 pis.). 
