404 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
but provided with a perianth in the Gnetacese. The absence of a perianth 
in the two first-named orders is not the result of degeneration. The 
“ cones ” of the Araucariese are not flowers, but spike-like inflorescences. 
The separation of the sexes is, on the other hand, a phenomenon of reduc- 
tion, the oldest forms having hermaphrodite flowers. The Gnetacese 
exhibit also reduction of the gynaeceum to a single carpel, and also in 
the number of the stamens. The Araucarieae have always only a single 
integument ; the outer integument of the Taxaceae is homologous to the 
carpid of the Araucarieas. Doubling of the stamens occurs for the first 
time in the male flowers of the Gnetaceae. We get in the Gymno- 
sperms the first manifestation of the spiral arrangement of the phyl- 
lomes, so common in Angiosperms. 
In the Monocotyledones we have a further advance in the differentia- 
tion of the perianth into calyx and corolla ; both whorls may be sepaloid, 
the outer sepaloid and the inner petaloid, or bctli petaloid. They cannot 
be regarded as metamorphosed stamens (except in Halophila). The old- 
est forms are unquestionably hermaphrodite. The typical flower of the 
Cyperaceae has 6 perianth-bristles, 6 stamens, and a 2-3-merous whorl 
of carpids ( Lejpidosperma ), the smaller number in other genera being the 
result of reduction. The Gramineae also exhibit all stages of reduction 
in the gynasceum from numerous carpels ( Ochlandta ) to 3 ( Strepto - 
chdeta), and 1 with a single stigma ( Nardus ) ; a corresponding reduc- 
tion taking place also in the number of the stamens. 
Structure of Pollen-Grains.* — Herr J. Balazs describes the form 
and structure of the pollen-grains of a number of plants belonging to the 
Angiosperms. He classifies them under 4 types, viz. : — (1) renifornT; 
(2) ellipsoidal ; (3) spherical ; (4) ellipsoidal, abruptly rounded at both 
ends. 
Structure of the Fruit in Ranunculaceae.t — Herr K. M. Wiegand 
classes the genera of Banunculaceae into 8 groups according to the struc- 
ture of the fruit, a classification which he believes also to represent their 
genetic affinity. The form and size of the embryo, the nature of the 
endosperm, the histology of the two integuments of the seed, and the 
form and structure of the pericarp, are described in detail for each genus. 
The author believes that the achene represents a reduced capsule (follicle), 
resulting either from contraction of the upper part and reduction of the 
ovules to one, as in Ranunculus, or from expansion of the ovary below 
with almost complete closing of the upper part, as in Clematis , Anemone, 
and other genera with pendent seeds. 
Micropyle of the Seed in Leguminosae.ij: — M. H. Coupin has studied 
the structure and development of the micropyle in a number of species 
of Leguminosae. He classifies the various forms under 4 types, viz. : — 
(1) a cup ( Vida Faba ) ; (2) a canal ( Cytisus ) ; (3) a closed cavity ( Lwpi - 
nus ) ; (4) indistinct ( Arachis ). In all cases the micropyle undergoes 
considerable changes during the development of the ovule into a seed. 
Except in the case of Abrus, the epiderm of the micropylar canal has 
* ‘Ueb. d. Pollen,’ Kolozsvar, 1896, 61 pp. See Bot. Centralbl., lxx. (1897) 
p. 156. 
t Proc. Amer. Micr. Soc., 1894, pp. 69-100 (8 pis.). See Bot. Centralbl., lxx. 
(1897) p. 211. X Rev. Gen. de Bot. (Bonnier), ix. (1897) pp. 175-80 (1 pi.). 
