TILIA 



Tiha, Linnaeus, Hort. Cliff. 204 (1735), Sp. PL i. 514 (1753), and Gen. PL 267 (1767); Bentham 

 et Hooker, Gen. PL i. 236, 986 (1862-7); V. Engler, Monog. Gatt. Ti/ia, pp. 1-159 (1909). 



Deciduous trees, belonging to the order Tiliaceae, with tough fibrous inner bark. 

 Leaves simple, long-stalked, alternate, arranged on the branchlets in two rows ; 

 unequal ' and cordate or truncate at the base ; acute or acuminate at the apex ; serrate 

 or toothed ; venation pseudo-palmate, the midrib giving off secondary nerves pinnately 

 on both sides, the lower two pairs of which arise together at the base, and give off 

 tertiary nerves on the outer side only. Stipules ligulate, membranous, caducous. 



Flowers white, fragrant, regular, perfect, in cymes ; peduncle connate with the 

 axis of a membranous elongated persistent bract, from the middle of which it 

 apparently arises ; inflorescence and bract springing from the axil of a leaf, alongside 

 a bud, which develops into a branch in the following year. 2 Sepals five, distinct ; 

 petals five, imbricate in bud. Staminodes either absent or present as petaloid scales, 

 one opposite each petal, and united with the base of the stamens. Stamens numerous, 

 free, or in five clusters united together at the base. Filaments unbranched, or forked 

 at the apex, with each branch bearing an extrorse half-anther. Ovary sessile, five- 

 celled ; style erect, dilated at the apex into five spreading stigmatic lobes ; ovules 

 two in each cell. Fruit nut-like, dry, indehiscent, one-celled, and one- to two-seeded 

 by abortion. Seeds obovate, with fleshy albumen. Cotyledons reniform or cordate, 

 palmately five-lobed, raised above ground on germination. 



In winter the twigs are zig-zag and bear lateral buds, disposed alternately in 

 two ranks ; each bud with two to three scales visible externally, ovoid, obliquely 

 displaced to one side of the semicircular leaf-scar, which is set on a prominent 

 pulvinus. Stipule-scars small, linear or oblong, one on each side of the leaf-scar. 

 Terminal bud absent ; a circular scar at the apex of the twig, opposite the uppermost 

 leaf-scar, indicating where the tip of the branchlet fell off in early summer. Base 

 of the branchlet girt with a ring of scars, due to the fall of the bud-scales in the 

 previous spring. 



About twenty species of Tilia can be distinguished. These are widely distri- 

 buted in the temperate regions of the northern hemisphere, extending southward 

 in North America as far as the highlands of Mexico ; but in the old world, while 

 common in Europe and in northern and eastern Asia, no species is known in 



1 Cf. Van Tieghem, in Ann. Sci. Nat. (Bot.) iii. 378 (1906), on the peculiar asymmetry in the leaves and stipules of 



the lime. 



2 The occurrence of an inflorescence and a normal bud in one and the same axil is unusual ; and is explained by the fact 

 that the former is the result of the very early development of a flower-bud under the first scale of the normal bud, the other 

 scales of the latter remaining dormant until the following season. 



VII 1653 B 



