TIMBER 651 



2-ranked arrangement. In the trees the shoots spread out horiz. and 

 the insertions of the 1. are upon the upper half, so that the divergence 

 is not \. The end bud of the branch does not develop in the next 

 year. Frequently the 1. is asymmetrical, with the smaller side towards 

 the branch. In the herbs the 1. are in two ranks diverging at a right 

 angle ; torsion of the 1. occurs later on and produces a dorsiventrality. 

 Theinfl.is always, at least after the first branching, cymose, and often 

 very complex, e.g. in Tilia and Triumfetta (</&) 



Fl. usu. ? , reg., 5 4-merous. K 5 or (5), v.ilvate : C 5, rarely o, 

 often glandular at base ; A usu. oo , free or united in groups, inserted at 

 base of petals or on androphore, with dithecous anthers ; G 2 oo -loc., 

 with i oo ov. in each ; ov. usu. ascending, anatr. ; style simple, 

 with capitate or lobed stigma. The T. yield usefiU timber, jute (Cor- 

 chorus) and other fibre. The most constant distinction from Malva- 

 ceae is in the dithecous anthers, from Theaceae in the valvate calyx, 

 &c Chief genera: Corchorus, Sparmannia, Tilia, Grewia, Triumfetta. 



Tiliacora Colebr. Menispermaceae. 8 Indomal. 



Tillaea Mich, ex L. Crassulaceae. 20 cosmop. (i Brit.). 



Tillaeastrum Britton (Tillaea pp.). Crassulaceae. 2N.Am. 



TUlandsia L. Bnnneliaceae (i) 250 warm Am. Some resemble the 

 rest of the fam. epiphytes with pitchers while others, and espe- 

 cially T. usneoides L. (long moss, Spanish moss, old man's beard, 

 vegetable horsehair), show a different habit, hanging in long grey 

 festoons from the branches of trees, looking rather like a lichen (esp. 

 Usnea). At the base, each of the pendent stems is wound round its 

 support, and as the apex grows on downwards the ol ler parts die 

 away, leaving the axile strand of sclerenchyma (the ' horsehair'). The 

 whole pi. is thickly covered with the usual scaly hairs for absorbing 

 the water trickling over it. It has no storage reservoir for water at 

 all. The fls. appear but rarely. The pi. is largely distributed from 

 tree to tree by the wind. Birds also use it for nesting and thus carry 

 it about. [See Schimper, Die epiph. Vegetat. Amerikas, p. 67, Plate II.] 

 It is used like horsehair. Some cult. orn. infl. 



Tiller, a sucker from base of stem. 



Tilmia O. F. Cook (Martinezia p.p.). Palmae (iv. 2). 2 trop. S. Am. 



Timber, any woody growth of sufficient thickness to be workable into 

 useful objects. The wood of a stem (Dicot.) grows in thickness, 

 adding one layer each year (in temp, zones), recognizable in cross 

 section as a ring of growth, or annual ring. In the trop., the rings 

 are not usu. so clear, and more than one may form in a year. In 

 longitudinal section (esp. radial), the medullary r.iys of the wood 

 show as the silver grain. As a rule the sap runs up in the outer part 

 of the wood (sap-wood or alburnum], while the inner part becomes 

 more dry and hard (heart-wood we duramen}. The pores in the wood 

 seen in cross section are the large vessels in which the sap runs, and 

 the greater the proportion of them (e.g. in climbing plants) the more 

 coarse-grained is the wood. 



Physical characters, such as hardness, weight per unit bulk, density 

 or compactness of grain, breaking strain, fuel value, and the like, are 

 also of great importance. 



By far the most important source of timber is the Coniferae (q.v.), 



