516 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVII. 



represented by Barleria acanthoides, a typical reck plant particularly abundant 

 round the e ges of the Jaisalmer plateau. Here it generally associated with 

 a grass, PappopJiorum aucherii and a small shrub, Grewia populifolia (Plate 

 XXXV- A.). The last mentioned plant, although preferring rocks, also frequents 

 other habitats. Another member of the Acanthacece, Buellia patula var. alba, 

 grows exclusively on rocks. It is absent from the Jaisalmer area. 



Cruciferce is a rare order in our region, and represented only by the genus 

 Farseiia. Of the two species collected, F. macrantha sp. nov. was abundant on 

 the Barmer hills, the only habitat. The order Violacece is represented by a 

 single species, the rock plant Viola stocksii, and this is rather rare, occurrins 

 only at Jaisalmer, Kotda and Barmer on our route. It is a poor looking plant 

 not much suggestive of the better favoured members of its genus. Polygala, 

 erioptera, a plant abundant throughout the region, often occurs on rocks, and 

 so do various Malvacece. Of the order Zygophyllacece, the commonest rock 

 plant is Fagonia cretica (Plate XXIV-A., XXVII-A.), but it is perhaps as 

 common on gravel. 



The order Geraniacece is represented by Monsonia senegalensis ; it is, 

 however, a raiher rare plant, the best locality observed being the flat top of a 

 small detached outlier of the Jodhpur plateau, along the road to Kailana. On 

 this hill-top (from which the general view shown in Plate VI-B. was taken), the 

 parasite Striga orobancheoides was abundant, and had a luxurious, much branched, 

 habit ; it grew on Lepidagathis trinervis, another typical rock plant (Plate 

 XXVII-A.) only observed in the Jodhpur area and at Bhikamkor. The hill 

 top was covered with grasses {Eleusine aristata and E. aegyptiaca, species of 

 Aristida), and Aerua tomentosa had been able to establish itself. 



Commiphoramuk^d{V\dXeYlll-B.)\s common enough on the rocky slopes 

 N-E of Jaisalmer, but otherwise rare. It has, like Euphorbia neriifolia, beer, 

 observed supporting Sarcostemma brevistigma (Plate VIII-A.), 



Of the order Lec/wminosce, the commonest rock plant is no doubt Indigofera 

 cordifoUa, which in some places, particularly round Kailana lake, literally col- 

 oured the hills gray. It associates with the two above mentioned species of Eleu- 

 sine, and Aristida funiculata. The plant is by no means bound to rocky habitats, 

 bemg equally abundant on gravelly soil. A typical inhabitant of rocky places, 

 however, is Tephrosia petrosa (sp. nov.), which is tolerably common in all the 

 three principal areas. 



The order Ficoidece, most members of which are gravel or sand plants, is 

 represented, on rocks exclusively, by Orygia deciimbens. This plant is common- 

 est in the Jodhpur and Barmer areas, being comparatively rare round Jaisal- 

 mer. and not observed at all on isolated hiUs. 



Of the Compositce, the most typical rock plant is perhaps Pegolettia senega- 

 lensis, which occurs throughout the region, but not very commonly. Many 

 species oiHeliotropium are to be found on rocks, although none exclusively. The 

 same may be said about various species of Convolvulus ; one new species of this 

 genus, C. gracilis, was however only observed on the Barmer hills, where it was 

 quite common. 



Salsola foetida was locally common near the top of the highest hill close to 

 Barmer. This plant was otherwise rare, being only observed in two places along 

 the northern part of our route growing on gravel. Another member of the 

 Chenopodiacece, Haloxylon recurvum, is a typical, though rare, rock plant, being 

 only observed on some isolated hills near Vinjorai and Kotda. In the former 

 localitythe species associated with the usual rock plants, chiefly with Orygia 

 decumbe7is. 



Another rare rock plant is Schweinfurthia sphcerocarpa (Plate 

 XXIII-B., (left) ; Anticliaris linearis, shown on the same plate, attains its best 

 development on g avel). The very common Bouchea^ marrubifolia, one of the 

 Verbenacecs is a typical rock plant, although rarely observed in other localities. 



