( 23 ) 



1. The arctic eubzone, from the arctic circle to 72 North Lat. Scanty vegetation. 



2. The circumpolar subzone, from 72 North Lat. to the pole. No vegetation. (?). 

 For convenience sake, I have marked off these zones and subzones at the geograpliioal 



lines, but these actually follow no mathematical lines, but are rectified by the lines of equal 

 summer and winter temperatures (isochimens and isotherms of the respective seasons, or 

 rather of the coldest and warmest months of the year). 



The whole Eastern Indian Flora belongs, according to my scheme, to the warm zone, 

 and the Pegu Flora, which we have here to consider more specially, would have to be placed 

 in the tropical subzone. 



It is usual to divide larger tracts into smaller or special zones, quite independent of the 

 zones above discussed, and so I do here. This is done to facilitate the understanding of the 

 distribution of plants and other peculiarities in climate, &c. 



The Pegu province does not bear an uniform Flora, but extends into the Ava tract. It 

 is, however, not necessary here, for the special purpose for which this report is written, to 

 make such a distinction of Floras. We shall, therefore, treat the part which belongs scienti- 

 fically to the Ava Flora, as a mere zone. 



From 3 it is already clear that the climate of Pegu allows of a division into zones, 

 each of which has its peculiarities, as well in vegetation, as in general appearance. I dis- 

 tinguish three principal zones in Pegu, viz. : 



1. The tidal zone, the limits of which may be drawn in a straight line from Bassein to 

 Khayazoo on the Sittang river, interrupted only by the Southern extremity of the Yomah that 

 terminates at Rangoon. The characteristic trees here are mangroves and other tidal trees. 



2. The Pegu zone, which extends over the whole province with the exception of an 

 almost rectangular tract at the North- Western corner. Owing to peculiar climatological 

 conditions, this zone might be subdivided into a Sittang and a Tharrawaddi district. The 

 former being the moister one, permits so many evergreens to immigrate from the Martabnn 

 hills as to make its Flora more allied in a botanical point of view to that of Martaban. The 

 Tharrawaddi district holds the mean between the Sittang district and the next or Prome zone. 

 True continuous evergreen forests (swamp-forests excepted) are here almost unknown, althouo'h 

 patches of evergreen trees form a substitute for evergreen forests in more sheltered valleys. 



It is interesting to observe here, how few of the evergreen trees of the Sittang district 

 cross the Yomah range into the Tharrawaddi district, although physical facilities do exist. 

 From the Arracan Yomah, which is said to be covered by evergreen forests, no evergreens 

 seem to come over the broad alluvium of the Irrawaddi. The true cause of this lies probably 

 in the unfavourable exposure of this side of the Yomah, and all the unfavourable climato- 

 logical changes that accompany such an exposure. 



3. The Prome zone, the line of which may be drawn from Myanoung on the Irra- 

 waddi to the top of the Kambala touug, and thence along the main range to tlie fron- 

 tier,* is the driest zone in the whole of Burma and is, so far as I could learn, quite destitute 

 of evergreen forests. Towards Mandalay in Ava the climate becomes so arid tliat there is 

 often not sufficient rain during the rainy season for the cultivation of rice. This dry Prome 

 (or more correctly Ava) climate allows such plants to grow, as Coch/ospermiun Goxsypinm, 

 TribuluH, Prka, Premna viburnoidcs, Roerhwwia repanda. Balanites, Azima, forests of Acacia 

 Cnfcchu, Celsia Coromandelinna, Polygala Vahliana, Decaschistia sp. near crofonifolia, Hilmcus 

 Solandra, Sebadirmia Chamnelea, Ruellia siijfruficosa, Andrograp/iu echioidcs, Porutropihe 

 calyciilatfi, Hohmkioldia sanguinea, Po/anisin Chelidomi, Pioralea corylifolia, Indigofera 

 Dtscosa, Ranunculus sce/erafus, Blepharis Maderaspufami, Bauhinia racemosa and B. diphylla. 

 Acacia Farnesiana, Rosa involucrala, Monenteles spicata, Carissn, ParMtn parriflora, Morinda 

 fomenfosa, Sphaeranthus amarantoides, Sfri/chnos potatorum, Hibiscus micranthiis, Artemisia 

 cirnifo/ia, Liii'iria ramosissima, Iphigenia indica, &c. All these are forms which remind 

 one of Hindostan, and most of them do not occur anywhere else in Burma, nor 

 in Arracan and Chittagong, but are found in the adjoining parts of Ava. The true 

 sal-tree {S/iorea rohusfa), is also said to occur further to the North, viz., in Avn, 

 and there is little cause left for hesitation to believe this, after such a number of Hin- 

 dostanee plants have been found, many of which even form the prevailing types of the 

 Prome Flora. The chief characteristic forms of Prome are Tectona llamiltonii (ta-hat) 

 Erijthrina sp. (eng kathit) Acacia leucophloeu (dha-noung), Hijmenopyramis brachiata, Capparis 

 grandis (Koungkwa) and very many others. 



Of course, none of these zones abruptly terminate at the lines drawn. As I hard- 

 ly need explain, they gradually merge one into the otlier. But along the main range 

 of the Yomah the division is rather abrupt ; for in travelling during March or April from 

 the Prome district to the Sittang side, a change is met with in the vegetation, when passing 

 the main range, which must impress any one, whether he be a careful observer or not. 



The country along the frontier North of Tounghoo is unkuown tome, but I have reason to suspect that 

 the line of the Ava zone extends to the Sittang along the watershed of the Loiiyaii choung. 



