ACER ii 



mangrove (g.v.) veg. Fl. a large bee-fl.; there is no upper lip to the 

 C, and the protection of the pollen, &c. is undertaken by the K. The 

 anthers form a box by fitting closely together at the sides, and shed 

 their pollen sideways into it, where it is held by hairs till an insect 

 probing for honey forces the filaments of the sta. apart and receives 

 a shower of pollen on its head (loose-pollen mechanism, cf. many 

 Scrophulariaceae, Ericaceae, &c.). In the young flr. the style is 

 behind the anthers, later on it bends down so as to touch a visiting 

 insect. The fr. explodes ; large 'jaculators' on the seeds. 



Acarna All. = Atractylis L. p.p. (Compos.). 



Acarodomatia, cavities mite inhabited, Anamirta, Fraxinus, Parameria. 



Acaulescent, almost stemless; acaulis (Lat. ), without visible stem. 



Accessory branch, bud, supernumerary in same axil, see Buds ; organs 

 of flower, the perianth. 



Acclimatisation, adaptation to new climate. 



Accrescent, enlarged and persistent. 



Accumbent, see Cruciferae. 



Aceituna. Symplocos. 



Acentra Phil. (Hybanthits Jacq. p.p. EP.) Violaceae. r Chili. 



Acer (Tourn.) L. Aceraceae (Sapind. BH. ). 1 1 5 N. temp., esp. in hill 

 districts (A. psendoflafanits L., sycamore, and A. campestris L. , 

 maple, in Brit., the latter native) and trop. nits.; many in China and 

 Japan. Trees and shrubs, with opp. exstip. 1., deciduous or ever- 

 green. L. often simple entire, more commonly 3- or 5-lobed, occa- 

 sionally cpd. One may go through a collection of A. in an herbarium 

 or elsewhere, comparing the 1. as to degree of development of the 

 drip-tips (acum. apices to easily wetted 1., from which the water drips 

 off rapidly after a shower, cf. Ficus) noting the kind of climate from 

 which each has come. There is a correlation between length of tip 

 and wetness of climate. 



Large winter buds, covered by scale 1. In many sp. transitional 

 forms may be seen as the bud elongates in spring, between the scales 

 and the green 1., showing that the scale = not the whole 1, but 

 the leaf base. In the Negundo there are no scales, but the bud is 

 protected by the base of the petiole of the 1. in whose axil it arises. 



The 1. commonly exhibit varnish-like smears, of sticky consistence, 

 known as honey-dew, the excretion of aphides which live on the 1.; 

 the insect bores into the tissues, sucks their juices, and ejects a drop 

 of honey-dew on an average once in half-an-hour. In passing under 

 a tree infested with aphides one may sometimes feel the drops falling 

 like a fine rain (see Pithecolobium). The fluid is rich in sugar. When 

 the dew falls the hygroscopic honey-dew takes it up and spreads over 

 the 1. ; then later in the day evap. reduces it to a varnish on the 

 surface. Many other trees exhibit this phenomenon, e.g. lime, beech, 

 oak (Btisgen, Der Honigthau, Jena). 



Fls. in racemes, sometimes contracted to corymbs or umbels, 

 reg., polyg., not conspic. ; formula usu. KS, C5, A4 + 4, G (2). 

 Apetaly in some. 3 cpls. are frequent, esp. in the end fl. of a raceme. 

 5 fls. protandrous ; honey freely exposed on the disc (fl. -class A), 

 available to insects of all kinds. Fr. a samara. In germination, the 

 long green cotyledons come above the soil almost at once. 



