B ETUI. A 
263 
Bertiera Aubl. Rubiaceae (1. B. 8). 15 sp. trop. Am., Afr., Madag., 
Masc. 
Bertiera Blume = Adenosacme Wall. 
Bertolonia Raddi. Melastomaceae (1). 10 sp. Brazil. Young plants 
form readily at cuts across the midrib of a leaf placed on damp soil 
(p- 113)- 
Bertya Planch. Euphorbiaceae (B. 11). 12 sp. Austr., Tasm. 
Berula Hoffm. ex Bess. = Sium Tourn. 
Berzelia Brongn. Bruniaceae. 7 sp. S. Afr. 
Beschorneria Kunth. Amaryllidaceae (11). 13 sp. Mex. Like Agave. 
Besleria Plum, ex Linn. Gesneraceae (1). 60 sp. trop. and sub-trop. Am. 
Bessera Schult. f. (excl. Androstephium Torr.). Liliaceae (iv). 1 sp. 
Mex. 
Beta (Tourn.) Linn. Chenopodiaceae (2). 6 sp. Eur., Medit. ; 1 in 
Brit., B. vulgaris L. or B. ?na?'itima L. the sea-beet, from which are 
derived the garden beetroot, the sugar-beet (var. Rapa Dumort.), and 
the mangold- wurzel. The plant is a biennial (p. 151) and stores 
reserves in the root, the non-nitrogenous materials taking the form 
of sugar. 
The sugar-beet is largely cultivated in Western Europe for the 
sake of its sugar, which has proved a very formidable rival to the 
older industry of cane sugar. The sugar-contents of the roots have 
been continually improved by selection, and now frequently represent 
over 20 °/o of the total weight. Germany grows ij million tons of 
beet sugar annually, and other countries about another 3 millions. 
[Herzog, Monographic der Zncker-riibe , Hamburg, 1899.] 
The garden beet is a favourite vegetable ; the mangold is valuable 
for feeding cattle, &c. The leaves of the beet are sometimes eaten 
like spinach. 
Betckea DC. = Plectritis DC. 
Betonica (Tourn.) Linn. = Stachys Tourn. 
Betula (Tourn.) Linn. Betulaceae. 35 sp. N. temp. B. alba L., the 
birch, is common in Brit, and reaches to the N. limit of trees (p. 180). 
The winter buds are scaly, the scales representing stipules : the outer 
two or three pairs of them have no leaves. The tree is of a singularly 
graceful habit. Witches’ brooms (p. 156) are very commonly to be 
seen as dense tufts of twigs. 
Trees with catkins of firs. The catkins are laid down in autumn 
as large buds at the end of the year’s growth, the ? further back, on 
leafy branches. In the axil of each leaf of the catkin there are 3 firs. 
(cf. other genera of the order). The bracts of the lateral firs, occur 
(a, / 3 ) but no bracteoles. In the S the bracteoles a /3 are joined to 
the bract itself. Each fir. has two sta. and a perianth, often 
reduced from the typical 4 leaves to the 2 median leaves, or even to 
the single anterior leaf. The sta. are divided into halves nearly to 
the base ; the lateral ones are absent. In the $ the bracteoles a ft 
