55i 
Knowledge of Rachiopteris cylindrica , Will. 
darkened outer cells of the cortex. It consists of regular thin-walled 
elements, which here and there have grown out to form root-hairs (Text- 
fig. 14, b). In another case root-hair production is shown in a very young 
root, the outer cortical cells of which are still unthickened. 1 
iii. Branching .—Occasionally lateral roots may be seen arising endo¬ 
genously opposite to the protoxylem groups of the main root; the process, 
however,'is too indistinct for detailed observation. 
IV. Organs in Association with R. cylindrica . 
In fairly constant association with the stems of Rachiopteris cylindrica 
are ‘ axes ’ of varying sizes, 2 and detached sporangia similar in type to those 
associated with Botryopteris ramosa , B. hirsuta , 3 4 and B. antiquah Although 
there is usually no evidence of their identity with R. cylindrica beyond 
that of association, this, and their suggestiveness when compared with 
similar structures referred to allied species, 5 entitle them to a brief 
description. 
1. ‘ Axes ’ of various orders . 
In several cases these detached ‘ axes ’ possess a monarch xylem- 
strand, similar to, but more robust than, the strand of /3 petioles (Text-fig. 15). 
Text-fig. 15. A monarch ‘axis’, associated with A*, cylindrica. px., protoxylem. x 80. 
(From slide K 21 d, University College, London.) 
The similarity of the cortex to that of a organs suggests that these axes are 
branches of the primary a petioles. 6 
1 So far as the writer is aware, this is the first record of undoubted root-hairs in a Coal Measure 
plant. 
2 Williamson (’ 78 ) mentions (p. 351), and figures (PI. 24, Figs. 81-3), axes much smaller 
than the main stems of R. cylindrica , and is inclined to regard them as branches of this plant. 
3 Scott (’ 08 ), pp. 332, 333; Fig. 125. 
4 Scott, D. H. : Sporangia attributed to Botryopteris antiqua, Kidston. Ann. of Bot., vol. 24, 
1910, p. 819. See pp. 819 and 820. 
Pelourde, F. : Observations sur quelques vegetaux fossiles de I'Autunois. Ann. des Sci. Nat, 
(Bot.), ser. ix, vol. 11, 1910, p. 361. See p. 367, Fig. 6. 
5 §ee Section V. 2, p. 538. 6 See p. 548, 
0 o 
