137 



pear near the cypress plantations would lead to the disappear- 

 ance of the pest, the fungus being then unable to complete its 

 normal life-cycle. 



Perhaps the most remarkable rust of all is that called Gam- 

 bleola cornuta which is often seen on Berberis nepalensis in 

 Jaunsar and near Mussoorie. It produces clusters of long, 

 black, wavy hairs on the under -surface of the leaves and some- 

 times on the twigs. Each hair consists of chains of teleuto- 

 spores which adhere closely to one another (see Plate XV, Fig. 5). 



122. Before leaving the great Lichens, 

 group of the Thallophytes, we must shortly consider 



the curious plants called Lichens. The general 

 appearance of a lichen is well known, viz. that of a crust on 

 stones, earth, trees, etc., of an irregularly shaped, foliaceous 

 structure adhering loosely to the substratum ; or again, that 

 of a tufted, shrubby mass of elongated branching processes, 

 such as is often seen festooning the stems and branches of trees 

 in cold damp forests of the Himalayas ; while others form 

 gelatinous, jelly-like masses. A lichen consists of two distinct 

 plants which live together, in partnership so to speak, one of 

 these partners being a fungus, usually belonging to the 

 Ascomycetes, and the other a minute alga. The green, 

 chlorophyll-containing cells of the latter are enmeshed in 

 the closely woven hyphae of the fungus, the latter being res- 

 ponsible for the general form and outline of the lichen. The 

 lichen is attached to the sub-stratum by root-like hairs, or 

 attachment organs, developed by the hyphae of the fungus. 

 The fructification of the lichen is developed by the fungus, but 

 the germinating fungus spores usually perish if unable to find a 

 suitable alga with which to enter into partnership. Lichens are 

 commonly reproduced by minute buds, each of which contains a 

 few algal cells entwined with hyphse. These are distributed by 

 the wind and grow into new lichens. The gelatinous lichens 

 are usually dark-brown, or olive-green, in colour, while others 

 ;are usually greyish-green, or yellowish. 



123. We now pass on to the Bryophytes. 

 second great sub-division of cryptogams, viz. the BRYOPHYTA. 



The plants in this sub-division are divided into two groups : 



(1) The Liverworts (Hepaticae). 



(2) The Mosses (Musci). 



Liverworts are minute plants of no forest importance which Liverworts, 

 may be found growing in damp soil, on rocks, tree-trunks and 

 even in the water. Many of them show no differentiation 

 into stem and leaves and possess a lobed thallus, thus resem- 



