256 APPEOT)IX. 



Boraginece. 

 Although this order is represented by 120 species and seventeen genera, it offers little 

 for remark here, no genus being endemic and ten of them having a wide range. About 

 half of the species are endemic and considerably more than half are South Mexican, 

 including both the woody and the herbaceous elements. The occurrence of the mono- 

 typic Harpagonella near Tucson, Southern Arizona, is curious, as the only other locality 

 known for it is Guadalupe Island, off Lower California. Omphalodes, otherwise an 

 Old- World genus, is represented by two somewhat anomalous species in North Mexico. 



Convolvulacece. 



The number and variety of species of the genus Ipomcea is the only noteworthy 

 feature of this order. Including Pharbitis, Quamoclit, Exogonium, Mina, Batatas, and 

 other proposed genera, Ijpomcea includes upwards of 300 species, of which about eighty 

 inhabit Mexico and Central America. They present great diversity in habit from 

 slender twining herbs to the arboreous form, as in /. murucoides and /. arborescens, the 

 latter being described as arbor procerrima. 



Solanacece. 

 Although generally dispersed in tropical and temperate regions, this order is pre- 

 eminently American, fifty-two out of sixty genera being represented, and forty-five of 

 them peculiar. Solanum itself, one of the largest genera in the vegetable kingdom, 

 numbering between 700 and 800 species, has nearly the same range as the order, and 

 is common in most warm countries, even where the species are few ; but by far the 

 largest aggregation of species is in America. Brazil alone possesses about 170; Chili 

 about fifty, and Mexico and Central America at least 100, after deducting about forty 

 which are either doubtful or better placed as varieties of others. After making the 

 deduction indicated and eliminating for the same reasons an equally large proportion of 

 the proposed species of Phy salts, Cestrum, and other genera, and leaving out the genus 

 Capsicum altogether, there are still 230 species of Solanaceee left within our limits, 

 belonging to twenty-six genera, two of which are endemic, and nineteen of the remaining 

 twenty-four are restricted to America. Only nine of the species extend beyond America, 

 and these are all widely diffused plants, mainly through cultivation. Apart from the 

 cultivated species of Nicotiana, which are now so widely colonized through cultivation, and 

 for other reasons to be left out of consideration, certainly indigenous species are found 

 only in America, Australasia, and Polynesia. A large number of the American genera 

 of Solanacese are wholly or largely western, ranging from California, where, however, 

 there are comparatively few, and no endemic genera, and Mexico to Chili, where the 

 order is largely developed. Of our genera ten and of our species thirty-one have 

 a north-western extension while the north-eastern extensions are five and two 

 respectively. 



