578 Goodlatte: The anatomv of Parosela spinosa 



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are no distinct bundles of secondary bast, not in direct contact 

 with the medullary rays and marked off by a distinct sTieath. On 

 the contrary, the secondary stereome is in direct contact with the 

 medullary rays and with the w^ood. The masses are composed 

 mainly of prosenchymatic or perhaps sclerenchymatic cells, while 

 those of the bast type, with long, pointed ends, are mixed with 

 them in small groups. 



The secretory system is extremely well developed, all the varie- 

 ties of internal secreting organs that are mentioned as occurring 

 in the tribe being found in this species. (This does not include 

 the glandular hairs possessed by a few Galegeae.) 



The material used for this work was, first, a dried herbarium 

 specimen which was soaked in a mixture of glycerine, alcohol, and 

 water, to make cutting possible, and afterwards some branches 

 that had been obtained in a living state, through the courtesy of 

 Dr. D. T. MacDougal, but were preserved in the same mixture. 

 Probably something in this method of preserving affected the secre- 

 tions of the glandular tissues. At all events, all tests for determin- 

 ing their exact contents were unsatisfactory, so that the only con- 

 clusion to be obtained is that, since they are analogous in anatom- 

 ical structure to the organs tested by other observers, their con- 

 tents are presumably of the same nature. 



Throughout the stem and spines there are strands of elongated 

 cells with thin walls and a large cavity, sometimes lying singly, 

 but more often two or three together, in the innermost layer of the 

 primary cortex. In some cases they are immediately adjacent to 

 the bundles of primary stereome, in others they lie opposite the 

 medullary rays (figure 5). Trecul found a similar set of cells 

 with tannin contents in the cortex and also on the outer edge of 

 the pith in Balea alopecuroides. He describes them as " ces sortes 

 de vaisseaux a tannin dont les cellules ne sont ordinairement per- 

 forees." Baccarini describes similar ducts in many Leguminosae, 

 which he says may appear in one stage of the plant's growth and 

 disappear subsequently, or may be permanent. These tannin ele- 

 ments are situated : i, around the pith and outside the stereome ; 

 2, in the periphery of the pith, grouped around the vascular apex 

 of the wood triangle of each bundle, and on the sides of the 

 stereome ; 3, around the pith, within the stereome and on its sides ; 



