518 JOURNAL, BOMBAY NATURAL RIST. SOCIETY, Vol. XXVIL 



soil just west of Loharki, this plant abounded, associated with scattered speci- 

 mens of Tribulus terrestris. Similarly Trianthema monogyna and T. hydaspica 

 covered large stretches of ground in and near the village of Seu. The latter 

 plant is absent in the east. 



We give a list of some other plants frequenting similar localities : various 

 species of Amarantihs, the commonest being A. polygamus ; several species of 

 Corchorus, Sida and Abutilon, particularly A. indicum ; Solanum nigrum and 

 S. xanthocarpum, the former absent in the west, the latter in the north ; Datura 

 fastuosa, not very common ; Tephrosia purpurea, chiefly in the east ; Euphorbia 

 granulata and E. microphylla ; Vernonia cinerea and Tridax procumbens, the 

 former near Jodhpur, Jaisalmer and Barmer, the latter only at Jodhpur ; Aris- 

 tolochia bracteata in the south-west ; Zygophyllum simplex, preferring rocks in or 

 about villages ; Boerhaavia diffusa, abundant everywhere (indigenous, chiefly a 

 gravel plant) ; Eragrostis viscosa about Jodhpur (several other species of this 

 genus may be counted as ruderals, preferring sandy soil in or about the villages). 

 The vegetation on the inner slopes of the pond-dam at Bap was characteris- 

 tic. It consisted of Trianthema triquetra and T. hydaspica, Limeum indicum, 

 Zygophyllum simplex and Salsola foetida (the last mentioned being a rather 

 rare plant, only observed at Sodakoer, and on the Barmer hills, where it was 

 common locally). At high-water level, there was a line of seedlings of Eclipta 

 erecta ; this plant, although ruderal, appears to be in great need of water, which 

 is the reason for our describing its behaviour at Barmer under the aquatic for- 

 mation. 



We noted the total absence of several ruderals, abundant in the Deccan, 

 such as Argemone mexicana, Opuntia, Saponaria vaccaria and Scoparia dulcis. 



B. Weeds of cultivation. 



This section consists of plants, unintentionally introduced together with 

 seeds and seedlings of cultivated plants, as well as of indigenous plants, preferring 

 cultivated ground. 



( 1 ) Weeds on sandy fields. 



These are not many. The commonest is Digre/" rtrwensis which is, however, 

 absent from the vicinity of Jodhpur, It is probably introduced. Mollugo hirta 

 may be referred here. It occurs only in the western half of our region, and is 

 probably also introduced. Gisekia pharnaceoides, an indigenous sand plant, 

 prefers cultivated ground. 



(2) Weeds on the fields with richer soil within the villages. 

 Unfortunately there are not many fields with a rich soil to be found. Plate 



XXVII-B. shows a field at Ba^arwa, entirely covered with Leucas aspera, other- 

 wise a rare plant, probably introduced. In the village mentioned, two other 

 species of the genus, L' nutans and L. stricta were collected, not observed any- 

 where else. L. urticcefolia is a proper ruderal, fairly well distributed, while L. 

 cephalotes was only found at Jodhpur and Mandor. Several species of 

 Alysicarpus, all introduced, and rare within our region, are found in similar loca- 

 lities. 



(3) Weeds of irrigated gardens and fields. 



Of these, the introduced Sesbania aculeata should be mentioned. Peris - 

 trophe bicalyculata, probably also introduced, frequents margins of irrigated 

 fields and irrigation channels. Of other plants, belonging here, we note parti- 

 cularly species of Ammannia and Bergia, also the semi-aquatic ruderal Eclipta 

 erecta. 



C. Escapes. 



One of the most remarkable plants of the region is Gitrullus vulgaris, the 

 water melon. It grows in almost every field of " Jowari " and " Bajri " 



