A Grammatical Dictionary of Botanical Latin

longitrorsum (adv.), also longitrorsus (adv.): longitudinally, lengthwise; cf. dextrorsum (adv.), to the right; cf. sinistrorsum (adv.), to the left;

- “sic dicitur, sicut dextrorsus, sinistrorsus, thus is it called, just as dextrorsus, sinistrorsus (Lewis & Short).

- pedunculi bearing 1-3 squamas longitrorsum dispositas gerentes, peduncles bearing 1-3 scales longitudinally arranged.

- [lichen] sporae 3-4-septatae (et parce longitrorsum divisae) (Nyl.),spores 3-4-septate (and slightly divided longitudinally.

- [Lichina; lichen] thallus fusco-ater fruticulosus cartilagineo-firmus intus longitrorsum parallele lineari-cellulosus (Nyl.), thallus a blackish-brown to dull black, fruticulose, cartilagineously-firm, inside longitudinally parallely linear-cellulose [i.e. with the cells in parallel linear lines].

- [lichen] sporae saepius 5-septatae (et varie longitrorsum divisae) (Nyl.), the spores more ofter 5-septate (and variously longitudinally divided.

- [lichen] thallus adpressus, saepius laciniaro-divisus, longitrorsum conferte acute rugulosus (Nyl.) the thallus appressed, more often laciniate-divided, lengthwise closely, acutely rugulose [i.e. with small wrinkles].