AMENTIFLORAE 
3 
Subclass 4. Heterochlamydeae (see Volume III). Inflorescence cymose or racemose, rarely 
solitary. Flowers usually monoclinous less often dioecious or diclinous, usually cyclic, sometimes spiral. 
Perianth usually dichlamydeous, rarely monochlamydeous and then either petaloid or sepaloid, rarely 
absent. Pollination usually entomophilous, less often anemophilous or autophilous. Ovary usually 
syncarpous, less often apocarpous or syncarpous only at the base. Fertilisation porogamous or very 
rarely mesogamous. Integument of seed double or single. 
Monochlamydeous forms occur in several families, e.g., Ranunculaceae, Rosaceae, Saxifragaceae. Mesogamous 
fertilisation has been observed in Alchemilla. Apogamously produced seeds occur, e.g., in Alchemilla. 
Subclass i. AMENTIFLORAE 
Amentiflorae nobis; Dicotyledoneae A et Ba Engler Syll. ed. 2, 100 (1898). 
The subclass Amentiflorae contains some of the most successful members of the class Dicotyledones if we judge 
from the standpoint of size, vegetative vigour, and longevity. It is an ancient group, being known in pre-Tertiary 
strata. However, they exhibit some signs of being a decadent race ; and, having probably given rise to no higher 
forms, it is natural to take them before the remaining subclasses, although, in our opinion, the lower members of the 
latter are as primitive and of equal age. In the characters of the flower, the Amentiflorae show signs of reduction 
from the hypothetical group of “primitive angiosperms” which preceded them and which gave rise to numerous 
diverging groups. One of the most remarkable of the specialised characters of the Amentiflorae is the method 
of fertilisation which occurs in many of the forms with the most reduced flowers, the pollen-tube, in the plants 
in question, entering the ovule at the chalazal end instead of through the micropyle as is ordinarily the case both 
in the Gymnospermae and the Angiospermae , and as was in all probability the case in the “ primitive angiosperms.” 
For characters, see page 2. 
British orders of Amentiflorae 
Order 1. Salicales (p. 4). Leaves simple, alternate, stipulate; stipules caducous or deciduous 
or persistent. Catkins simple. Bracts 1 to each flower. Flowers dioecious. Perianth either small 
and usually undivided or modified into 1 — 4, usually 1 or 2 nectaries. Stamens 2 to 00 . Ovary of 2 
(sometimes apparently 3 or 4) carpels, unilocular ; placentation parietal ; ovules 00 in each loculus, 
anatropous, with a tuft of long white hairs arising at the base ; fertilisation porogamous. Fruit a 
loculicidal capsule, free from the bract. Seeds small, 00 ; hairs persistent ; endosperm absent ; integu- 
ment double. 
Order 2. Myricales (p. 69). Leaves simple, alternate, stipulate or not ; stipules caducous. 
Catkins simple. Bracts and bracteoles persistent, glandular. Flowers monoecious and diclinous, or 
dioecious. Perianth absent. Stamens 2 to 16. Ovary of 2 carpels, unilocular ; placentation basal; 
ovules 1 to each ovary, orthotropous, glabrous ; fertilisation porogamous. Fruit a nutlet (in the 
British species), adherent to the enlarged bract and bracteoles. Seeds 1 to each ovary, glabrous ; 
endosperm absent ; integument single. 
Order 3. # Juglandales (p. 70). Leaves pinnate, alternate, exstipulate. Catkins simple. Flowers 
monoecious and diclinous. Bracts and 2 bracteoles persistent. Perianth small, with usually 4 (rarely 
fewer) segments. Stamens 3 to 40. Ovary of 2 carpels, unilocular ; placentation basal ; ovules 1 to 
each ovary, orthotropous, glabrous ; fertilisation chalazogamous. Fruit a pseudocarpous “ drupe ” 
consisting of the ovary fused with the bracts and bracteoles. Seeds 1 to each ovary, glabrous ; endo- 
sperm absent ; integument single. 
Order 4. Fagales (p. 71). Leaves simple, alternate, stipulate; stipules usually caducous. Catkins 
simple or compound. Bracts and bracteoles persistent. Flowers monoecious and diclinous. Perianth 
small and usually deeply divided, or absent. Stamens 2 — 00 . Ovary with 2 to about 9 carpels and 
as many loculi and stigmas ; placentation axile or pendulous ; ovules 1 or 2 to each loculus, but only 1 
ripening, anatropous, glabrous ; fertilisation porogamous or chalazogamous. Fruit a nut or small 
samara, often more or less enclosed by a “cupule” of persistent bracts and bracteoles. Seeds 1 to 
each ovary, glabrous ; endosperm absent ; integument double or single. 
Order 5. Urticales. Leaves simple, alternate or opposite, stipulate ; stipules persistent or not. 
Inflorescence catkinoid or cymose. Flowers dioecious, or monoecious and diclinous, or monoclinous. 
Perianth small, often campanulate. Ovary of 1 or 2 carpels, usually unilocular ; placentation 
basal or pendulous ; ovules i to each loculus, orthotropous, anatropous, or amphitropous, glabrous ; 
fertilisation porogamous, mesogamous, or chalazogamous. Fruit (in the British species) a samara or 
achene. Seeds 1 to each loculus, usually with endosperm, glabrous ; integument double. 
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