280 
CALLITRICHA CEAE 
Hooker unite C. with Haloragidaceae, but the differences between 
the two are considerable. They have also been placed near Caryo- 
phyllaceae, Verbenaceae, Boraginaceae, &c. , but seem on the whole 
nearest to Euphorbiaceae, where they are placed by Engler and by 
Eichler and Warming (Tricoccae). 
Callitriche Linn. Callitrichaceae. 25 sp. (probably only varieties of 
1 or 2), cosmop. (exc. S. Afr.). Several forms of water star- wort are 
common in Brit. The submerged leaves are longer and narrower 
than the floating, and the more so the deeper they are below the 
surface. Land forms also occur. Fir. unisexual, naked, commonly 
with 2 horn-like bracteoles, protogynous; S of 1 sta. ; ? of (2) cpls., 
transversely placed, 4-loc. by ‘ false * septum (cf. Labiatae), with 2 
styles. 1 ovule in each loc. , pendulous, anatropous with ventral 
raphe. Schizocarp. Seed with fleshy endosperm. The modes of 
fertilisation of the firs, are not very clearly made out. 
Callitris Vent. Coniferae (Arauc. 2 a; see C. for genus characters). 15 
sp. Afr., Madag., Austr., New Caled. Leaves and cone-scales in 
whorls. The cone ripens in 1 or 2 years. C. quadrivalvis Vent. (N. 
Afr.) yields Arar wood and Sandarach resin or pounce. 
Calluna Salisb. Ericaceae (iv. 9). 1 sp., C. vulgaris Salisb., the 
heather or ling, widely distributed over Eur. and found in Greenland, 
and from Newfoundland to Massachusetts (the only representative of 
Ericoideae in Am.). It covers large areas in these regions, together 
with sp. of Erica and Vaccinium. It is a low evergreen shrub, with 
linear closely crowded wiry leaves and racemes of firs. The calyx is 
coloured like the corolla and the latter is almost polypetalous. The 
honey is much more easily accessible than in Erica and there is a 
larger circle of visiting insects, including however many bees (heather 
honey is the most valuable of all kinds). The stigma projects beyond 
the mouth of the fir. ; insects touch it first and in probing for honey 
jostle the anthers. The fir. is also wind fertilised; the loose powdery 
pollen blows about very easily and the stigma is not covered by the 
corolla. 
Calochilus R. Br. Orchidaceae (4). 3 sp. E. Austr. 
Calochortus Pursh. Liliaceae (v). 30 sp. W. N. Am. 
Calodendron Thunb. Rutaceae (iv). 1 sp. S. Afr. 
Calonyction Choisy. = Ipomaea Linn. 
Calophaca Fisclu Leguminosae (111. 6). 10 sp. S. Russia to Burmah. 
Calophanes D. Don. Acanthaceae (iv. a). 40 sp. trop. 
Calophyllum Linn. Guttiferae (ill). 55 sp. trop., chiefly Old World. C . 
Tacamahaca Willd. and other sp. yield resins known as Tacamahac. 
[See Populus.] 
Calopogon R. Br. Orchidaceae (14). 4 sp. U. S. 
Calothamnus Labill. Myrtaceae (11. 2). 23 sp. W. Austr. The axis 
goes on bearing leaves beyond the firs. (cf. Callistemon). Sta. in 
bundles before the petals, the common axis of the bundle very large. 
