244 CONTRIBUTIONS TO 



They occur in the epidermis of the pericarp in many Labiates, 

 as in Ziziphora, Ocymum ; in most Salvias, for instance, Urn- 

 bata, hispanica, Spielmanni, &c. ; and lastly, in Horminum 

 pyrenaicum. My uncle Horkel was familiar with them in all 

 these many years ago; Baxter noticed and published their 

 occurrence in Salvia verbenacea only. I can add to these 

 Dracocephalum moldavica. 



R. Brown discovered them in the parenchyma of the peri- 

 carp in the Casuarinoe, and I in the spongy inflated cellular 

 tissue in Picridium vulgare, where they mostly occur in a 

 reticular form, and present an extremely beautiful appear- 

 ance. 



Horkel also discovered them in the epidermis of the seed 

 itself in the Polemoniacece long before Lindley made known 

 their presence in Collomia linearis. They occur in Collomia, 

 Gilia, Ipomopsis, Polemonium, Cantua, Caldasia, and perhaps in 

 the entire family, with the exception of Phlox, with which 

 genus Leptosiphon, in which are the first indications of them, 

 is closely allied. Horkel had also studied them in the seeds 

 of Hydrocharis, where they occur in the highest degree of deve- 

 lopment, long before Nees von Esenbeck published the fact. 

 Robert Brown mentions them in the Orchidece, which statement 

 I find confirmed as to most of our native species of Orchis. 

 I have also discovered very beautiful spiral fibre-cells in the 

 epidermis of the seed of Momordica elaterium, and a very deli- 

 cate reticular formation of fibres in Linaria vulgaris, Datura 

 stramonium, in Salvias, and in several other Labiates ; probably 

 it is common to the whole family. 



Lastly, they occur, according to HorkeFs discovery, in the 

 parenchyma of the integuments of the seed in Cassyta and 

 Punica. 



Whether these formations be studied in their individual 

 development in a single species, or in their progressive stages 

 in a series of allied plants, some highly interesting general re- 

 sults will be obtained in either case. The universal and alto- 

 gether absolute fact at which we first arrive is, that the fibres 

 are never formed free, but are developed in the interior of 

 cells ; and that the walls of these cells in the young state are 

 simple, and generally very delicate. Corda's statement re- 

 specting spiral cells without an enveloping membrane (Ueber 



