ALBIZZIA 
227 
Ailanthus Desf. Simarubaceae. 4 sp. Ceylon, Ind., China, Austr. 
A . glandulosa Desf. (tree of heaven) is a favourite in parks. 
Absciss layers are formed at the base of the leaflets as well as of 
the main petiole; the leaflets usually drop first (p. 156). 
Ainsliaea DC. Compositae (xn). 16 sp. India to Japan. 
Ainsworthia Boiss. = Tordylium Linn. 
Aiouea Aubl. Lauraceae (11). 8 sp. trop. Am. 
Aira Linn. Gramineae (ix). n sp. chiefly Eur., Afr. , 2 in Brit, 
(hair-grass). For A. caespitosa Linn, and A. flexuosa Linn, of the 
British flora, see Deschampsia, and for A. canescens Linn, see 
Corynephorus. 
Airopsis Desv. Gramineae (ix). 1 or more sp. S. Eur., Afr. 
Aizoaceae ( Ficoideae of Bentham and Hooker). Dicotyledons (Archichl. 
Centrospermae). 18 genera with 420 sp. chiefly S. Afr., but also in 
Calif., S. Am., trop. Afr. and As., Austr. They are nearly allied to 
the other Centrospermae, but have been placed in various other 
relationships by different authors (near Cactaceae by Bentham and 
Hooker). Xerophytic herbs with opp. or alt. exstip. leaves, often 
fleshy, and with cymes of firs. The anatomy is of interest (see Nat. 
Pfl •). Typical formula P 5 or (5) (odd leaf posterior); A 5; G (3), 
3-loc. with 00 ovules in each loc. Dedoublement is very common in 
the androeceum, and in these cases, e.g. Mesembryanthemum, the 
outer sta. are frequently represented by petaloid staminodes. The 
ovary is usually sup. with axile placentae, but in Mesembryanthemum 
it is inf., multiloc. with parietal placentae, a very unusual feature 
brought about during development (see M.). Fruit usually a capsule ; 
seed albuminous with curved embryo. 
Classification and chief genera (after Pax) : 
I. MOLLUG1NOIDEAE (perianth deeply 5-lobed : “petals” 
or not : ov. sup.) : Mollugo, Orygia. 
IL FICOIDEAE (perianth tubular): 
1. Sesuvieae (ov. sup.; capsule with lid): Sesuvium, 
Trianthema. 
2. Aizoeae (do. ; capsule splitting) : Galenia, Aizoon. 
3. Mesembryaiithemeae (ov. inf.) : Tetragonia, Mesembry- 
anthemum. 
Aizoon Linn. Aizoaceae (11. 2). 10 sp. Afr., Medit. Sta. 00 in bundles. 
Ajuga Linn. Labiatae (1. 1). 30 sp. temp., 3 in Brit., incl. A. rcptans 
L., the bugle, and A. Chamaepitys Schreb., the yellow bugle or 
ground-pine. The sta. are protected by a large bract, and the corolla 
has no upper lip. Vegetative reproduction by runners. 
Akefoia Dene. Lardizabalaceae. 2 sp. China, Japan. A. quinata 
Dene, is often cultivated. Its firs, are monoecious, the lower in 
the raceme usually ? . The ? is much larger than the c? , a very 
unusual thing. The berries dehisce like follicles. 
Alangium Lam. Cornaceae. 7 sp. palaeotrop. 
Albizzia Durazz. Leguminosae (1, 1). 50 sp. trop. and subtrop. Old 
I 5— : 2 
