66 AZALEASTRUM 



Azaleastnun Rydb. (Rhododendron p.p.)- Ericaceae (i. 2). i N. Am. 



Azara Ruiz et Pav. Flacourtiaceae. 20 Mcx., S. Am. Shrubs with 

 alt. 1. ; one stip. is frequently almost as large as the 1. to which it 

 belongs, giving the appearance of a pair of 1., not opp. Fl. apetalous ; 

 outer sta. often without anthers. 



Azedarach Tourn. ex L. = Melia L. (Meliac.). 



Azeredia Arruda (Cochlospernmm p.p. EP.}. Cochlosperm. i Brazil. 



Azima Lam. Salvadoraceae. 3 S. Afr. to Phil. Is. In the axils are 

 thorns (the 1. of an undeveloped shoot, cf. Cactaceae). Polypet. 



Azolla Lam. Salviniaceae. 4 trop. and subtrop. General structure 

 like Salvinia. Two 1. are formed at each node, from (he dorsal half 

 of a segment of the apical cell ; from the ventral half are formed roots 

 and branches, but not at every node. The 1. are all alike ; each is 

 bilobed and has a small cavity near the base, opening by a small 

 pore, and inhabited by the Alga Anabaeita. The r. hang freely 

 down in the water ; usually the root cap is thrown off after a time 

 and the r. comes almost exactly to resemble the submerged 1. of 

 Salvinia. The sporocarps are formed in pairs (4 in A. mlotica] on 

 the ventral lobes of the first 1. of the branches. Each contains one 

 sorus. The microspores are joined together into several masses in 

 each sporangium by the hardened frothy mucilage (epispore, cf. Sal- 

 vinia). Each of these massulae has its outer surface provided with 

 curious barbed hairs (glochidia), and escapes on its own account. 

 The megasporangium contains one spore. It sinks to the bottom ; 

 decay of the indusium frees the spore and it germinates, giving rise 

 to a ? prothallus which floats about on the water and may be anchored 

 to a floating massula by the barbs. 



Azorella Lam. Umbelliferae (i. 2). 70 Andes to N.Z. Densely tufted 

 xero. A. caespitosa Vahl. (balsam-bog, Falklands) forms tufts like 

 Raoulia. 



Azureus (Lat), sky-blue. 



B (fl. -class), fls. with fully concealed honey, Calluna, many Caryophyl- 

 laceae, Geranium, Gypsophila, Polemoniitm, Rnbiis, Thy tints. 



B' (fl. -class), like B, but aggregated into dense heads, Armeria, Coni- 

 positae, Dipsaceae, Scabiosa. 



Babbagia F. Muell. (Osteocarpum EP.}. Chenopodiac. 4 Austr. 



Babiana Ker-Gawl. Iridaceae (in). 40 S. and trop. Afr., Socotra. 



Babingtonia Lindl. = Baeckea L. p.p. (Myrt.). 



Babul, Acacia arabica Willd. 



Bacca (Lat.), a berry; -cate, with berry; -iform, berry-like. 



Baccaurea Lour. Euphorbiaceae (A. I. i). 60 trop. Afr., As., Polynesia. 



Baccaureopsis Pax. Euphorbiac. (A. i. i). i trop. Afr. 



Baccharis L. Compositae (3). 380 Am., esp. campos. Many are 

 leafless xero. with winged or cylindrical green stems (Bot. Jb. 

 27, 446). 



Bachelor's button, double fld. Centaurea, Lychnis, Ranunculus, &c.; 

 also Jasione, &c. ; do. (W.I.), Goniphrena. 



Bachmannia Pax. Capparidaceae (11). 2 Pondoland. 



Bacillar, rod-shaped. 



Backhousia Hook, et Harv. Myrtaceae (n. i). 5 E. Austr. B. citrio- 

 dora F. Muell. gives an essential oil almost entirely citral. 



