230 
ALISMA CEAE 
and trop. Mostly water or marsh herbs with perennial rhizomes. 
Leaves various, erect, floating, or submerged and exhibiting structure 
corresponding to their conditions of life (see p. 160 and Sagittaria, 
Elisma, &c.). In the leaf axils are small scales. Laticiferous ves- 
sels occur. Infl. usually much branched, the primary branching race- 
mose, the secondary often cymose. Fir. 5 or $ ? , regular, with 
perianth of 6 leaves in tw’o whorls, the outer sepaloid, the inner 
petaloid. Sta. 6-oo , with extrorse anthers. Cpls. 6- oo , apocarpous, 
superior, with i (rarely 2 or more) anatropous ovule in each. Fruit 
a group of achenes ; seed exalbuminous ; embryo horse-shoe shaped. 
Chief genera : Alisma, Elisma, Damasonium, Sagittaria. [Benth.- 
Ilook. unite A. w 7 ith Butomaceae, placing them in Apocarpae.] 
Alkanna Tausch. Boraginaceae (iv. 3). 30 sp. Medit. &c. The 
root of A. tinctoria L. furnishes the red dye, alkanet or alkannin. 
Allamanda Linn. Apocynaceae (1. 1). 12 sp. trop. Am. and W. Ind. 
Alliaria Marsh. = Sisymbrium L. (A. offic. DC. =S. Alliaria Scop.). 
Allionia Loefl. Nyctaginaceae (1). 1 sp. Am. Anthocarp glandular 
(cf. Pisonia). 
Allium (Tourn.) Linn. Liliaceae (iv). About 250 sp. N. temp. A. ur - 
sinurn L. (garlic), A. Schoenoprasu?n L. (chives), and 6 others, in Brit. 
A. Cepa L. (Persia, &c.) is the onion, A . Porrum L. (Eur.) the leek, 
A . ascalonicu 7 ?i L. (Orient) the shallot, A . sativum L. (S. Eur.) the 
garlic. All are bulbous herbs with linear (or hollow centric) leaves 
and cymose umbels of firs. In many sp. the firs, are replaced by 
bulbils serving for vegetative reproduction (cf. Lilium). In A. ur - 
sinum, &c. honey is secreted by the septal glands of the ovary ; the 
protandrous fir. is visited by bees and flies. 
Alloplectus Mart. ( Crantzia Scop.) Gesneraceae (1). 35 sp. trop. Am. 
Allosorus Bernh. = Cryptogramme R. Br. 
Almeidea St. Hil. Rutaceae (v). 10 sp. Brazil. 
Alnus (Tourn.) Linn. Betulaceae. 14 sp. N. temp. (A. glutinosa 
Medic., the alder, in Britain.) Like Betula in most features. In the 
axil of each bract of the $ catkin are 3 flowers (see diagram of the 
order, and cf. other genera) each with 4 stamens and 4 perianth 
leaves. The bracteoles a, /?, / 3 ', / 3 ' are present. Stem. 
(See diagram.) All these leaves are united with fir. fir. flr. 
one another. In the ? catkin only two, the ( 3 ' (S' 
lateral, flowers occur, and the same bracts. After a (3 
fertilisation, the ovary gives a one-seeded nut, bract. 
under which is found a 5-lobed scale, the product of subsequent 
growth of the 5 leaves. The flower is chalazogamic (see p. 81 and 
art. Chalazogamae). 
Alocasia Neck. Araceae (vi). 20 sp. E. Ind. Herbaceous. Monoe- 
cious. “ A. odora , C. Koch, is supposed by Delpino to be fertilised 
by snails. The spadix is covered in its whole length with normal 
and abortive stamens and pistils ; only ? flowers occur in the lower 
