1654 The Trees of Great Britain and Ireland 



northern Africa or in the Himalayas. A large number of hybrid forms have arisen, 

 some of which are common in cultivation. The following key, based on the 

 characters of the branchlets and leaves, will serve to distinguish the species and 

 hybrids which are cultivated in this country. 



I. Leaves green beneath, with axil-tufts of pubescence, but without any 



STELLATE TOMENTUM. 



(a) Axil-tufts 1 present at the base of the leaf and elsewhere. 



* Branchlets glabrous, or nearly so. Leaves glabrous, except for axil-tufts beneath. 



1. Tilia mongolica, Maximowicz. North China and Mongolia. See p. 1679. 



Branchlets quite glabrous, reddish. Leaves 2^ in. wide, often trilobed, 

 glaucous beneath with non-prominent tertiary veins, coarsely toothed. 



2. Tilia cordata, Miller. Europe, Caucasus. See p. 1656. 



Branchlets slightly pubescent at first, speedily becoming glabrous. Leaves 2 to 

 2 \ in. wide, bluish green beneath with non-prominent tertiary veins, finely serrate. 



3. Tilia vulgaris, Hayne. A hybrid, occasionally wild in Europe. See p. 1664. 



Branchlets quite glabrous. Leaves 3 in. wide, dull green above, pale green 

 beneath and with prominent tertiary veins, finely serrate with short points to the 

 teeth. 



4. Tilia euchlora, Koch. A hybrid, occasionally wild in the Caucasus. See p. 1674. 



Branchlets usually quite glabrous. Leaves 2\ to 3 in. wide, dark shining 

 green above, pale green beneath and with prominent tertiary veins, finely serrate 

 with long points to the teeth. 



** Branchlets densely pubescent with long hairs. 



5. Tilia platyphyllos, Scopoli. Europe. Seep. 1661. 



Leaves 3 to 4 in. wide, upper surface with short scattered pubescence, lower 

 surface covered with long hairs. 



(b) Axil-tufts absent at the base of the leaf present elsewhere. 



6. Tilia americana, Linnaeus. North America. See p. 1685. 



Branchlets glabrous. Leaves 5 to 6 in. long and 3^ to \\ in. wide, broadly 

 ovate, cordate at the base, glabrous beneath and with numerous prominent 

 parallel tertiary veins ; margin with long-pointed coarse serrations. 



7. Tilia paucicostata, Maximowicz. Western China. See p. 1680. 



Branchlets glabrous. Leaves 2\ in. long and 2 in. wide ; ovate, usually 

 truncate at the base, glabrous beneath with few prominent irregular tertiary 

 veins ; margin with long-pointed fine serrations. 



I I. Leaves green or greyish beneath, with scattered stellate tomentum. 



(a) Under surface of the leaves without axil-tufts, but with 

 long hairs on the midrib. 



8. Tilia Moltkei, Schneider. Seep. 1686. 



A hybrid, with large leaves similar to those of T. americana in shape and 

 serrations. Buds and branchlets glabrous. 



1 These are tufts of hairs at the junctions of the midrib and lateral nerves on the under surface of the leaf, which are now 

 often termed domatia ; they are the abodes of mites, and serve a useful purpose in the economy of the tree. They were fully 

 studied and described by Lundstrom, in Nov. Act. Reg. Soc. Sci. Upsala, xiii. pt. 2, pp. 3-10 (1887). Cf. Lord Avebury, 

 Brit. Flowering Plants, 123 (1905), 



