167 



increased luxuriance, which is favoured by the free space allowed to 

 it in the garden. 



Tolpis umbellata {Bert.) and Tolpis crinita {Lowe).—Tho^e charac- 

 ters which are sufficient to warrant the assignment of plants to two 

 different genera, should be of a more important kind than are the cha- 

 racters which suffice only to distinguish two species of the same ge- 

 nus. In the Prodromus of DeCandolle, the Tolpis umbellata and T. 

 crinita, though brought under the same genus, are assigned to differ- 

 ent sections of their genus. These sections represent the genera of 

 other authors, Drepania and Schmidtia, founded on differences in the 

 pappus of the fruit, akin to those which separate Thrincia from Leon- 

 todon. In the year 1842, I collected specimens and seeds of Tolpis 

 crinita in the Azores. The specimens corresponded with one from 

 Madeira, which was given to me under the same name by Dr. C. Le- 

 mann, who has enjoyed the best opportunities for becoming well ac- 

 quainted with Mr. Lowe's plants. The seeds were sown in my garden, 

 and produced plants which I could refer only to T. umbellata, I com- 

 municated one of these living examples to Dr. Lemann, and he wrote 

 me that the plant was T. umbellata ; thus corroborating my own view 

 of them, and showing that Tolpis (Drepania) umbellata and Tolpis 

 (Schmidtia) crinita are not permanently distinct species — much less 

 distinct genera. This instance, if so explained, may be considered a 

 case of unnecessary " hair-splitting " in the formation of genera. Or, 

 on the other side, the transitionist may argue that characters which 

 have been deemed sufficient to separate genera, may be acquired and 

 lost in such manner as should throw doubt on the supposed impassa- 

 ble distinctions of species. 



Orchidaceous genera. — Mr. Schomburgk published a paper in the 

 Linnean Transactions, to show that orchidaceous epiphytes, referred 

 to three different genera by first-rate authorities in this order, could 

 change into or produce one another. One of the plants " produced a 

 scape with six flowers of Monachanthus viridis and two of the Myan- 

 thus barbatus, while a second scape of the same bulb had twenty-five 

 blossoms of the Myanthus barbatus." The same combination of ge- 

 nera occurred on a second plant in another collection. A third plant 

 produced the flowers of Monachanthus viridis at one period, and 

 those of Catasetum tridentatum at another time. And on Mr. Bach 

 sowing the seeds of Monachanthus viridis, one among the plants pro- 

 duced a scape with the flowers of Catasetum tridentatum. Here, also, 

 it may be said that the plants had been incorrectly described as dif- 

 ferent species and genera. But the fact still shows that cases of tran- 



