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CONTRIBUTIONS FROM THE SHAW SCHOOL OF BOTANY. 

 No. 1. 



On the Pollination of Phlomis tuberosa, L., and 

 the Perforation of Flowers. 



By L. II. Pammel. 



Last spring my attention was drawn to a rather large and 

 conspicuous cluster of Phlomis tuberosa growing in the Botanic 

 Garden The species is a native of Europe and has become spar- 

 ingly naturalized in the United States. The pollination of this 

 species seems not to have been studied, although we have an ad- 

 mirable account of the pollination of Phlomis Russeliana by Loew. 

 Our species, altliough agreeing in some important particulars 

 with the Syrian, differs in color and some other minor points. 



The structure of the flower clusters is that common to many of 

 the Labiates, in that the flowers are borne in cymose axillary 

 clusters ; but in this case the clusters are very dense, so that the 

 flowers are not separated readily. The tubular calyx is lo-ribbed, 

 and terminates rather abruptly in 5 awns. 



A plant when in flower is very conspicuous not only from the 

 purple color of the corollas, but also from the number of flowers 

 open at the same time, as there are often as many as six or eight 

 in one cyme ; and on going to the ffower at any time of the day, 

 one could see several species of Bombus and a Xylocopa collect- 

 ing nectar, besides other small Hymenoptera which principally 

 collected pollen. The corolla is decidedly two-lipped. The up- 

 per lip arches over the lower, and is slightly notched. At the time 

 of pollination the upper lip lies close to the lower, so that a hum- 

 ble-bee on entering the flower must force the former back, when 

 its thorax is dusted with pollen from the anther cells which lie 

 among the rather numerous hairs in the arched upper lip. This 

 lip readily returns to its former position on account of the elastic- 

 ally-hinged arrangement to be found on its posterior part close to 

 the tube of the corolla. This arrangement is also described by 

 Loew (6i a, 62) as occurring in Phlomis Pusseliana, and has been 

 called by him "Charnier Gelank." MacLeod (68) flnds a similar 



v. — I — 16 [Jun aS, iSSS. 



