THE GFA T US TALIMM IN MEXICO. 



By J. N. Rose and Paul C. Standley. 



The genus Talinum, like other genera of the Portulacaceae and 

 many groups of succulents, has been much neglected because of the 

 difficulty of preparing good herbarium specimens of the plants. 

 Dried material of this genus is usually unsatisfactory and permits 

 one to form only an imperfect idea of the plants as they appear while 

 growing. Commonly only the ends of branches are preserved, thus 

 hiding their habit; and often the flowers, which furnish a means of 

 distinguishing species, are so poorly pressed that even their color is 

 lost. This is especially true of the flat-leaved Talinums. For this 

 reason most students of the genus have grouped all its representatives 

 under a few of the earlier published names. 



During the last few years different collectors have sent to Wash- 

 ington living plants of various species of the genus. Many of these 

 have thrived in the greenhouse and flowered at the proper season. 

 With these living plants, and with additional herbarium material 

 that has lately come to hand, we are able better to understand their 

 peculiar characters and to use for diagnostic purposes some of these 

 not readily perceptible in dried material and not before made out. 

 As a result we have discovered a number of types that seem worthy 

 of specific segregation. 



The species of Talinum found in Mexico fall somewhat naturally 

 into four groups. The first consists of those having terete leaves. 

 All these are very much alike in habit, but differ in other and essential 

 characters. Some have red, some yellow, and some white flowers. 

 Of the flat-leaved plants the larger ones, those with their inflorescence 

 in a compound panicle, like T. pardculatum, form a group composed 

 of two species. Another group consists of plants of lower habit with 

 inflorescence usually in the form of simple racemes, never a true 

 panicle, typified by T. triangulare. Still another contains low plants 

 with flat but very narrow leaves, like T. lineare; in these the inflores- 

 cence is axillary. This seems to be intermediate between the species 

 having terete leaves and those with broad and flat ones, although 

 more closely related, perhaps, to the latter. To be associated with 

 the last group, but still so different as to appear almost anomalous, is 

 a species lately described, T. oligospermum, with flat and narrow but 



verv thick leaves. 



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