7mm longa obtusa. Coronae squamae planae membranaceae sejunctae oblongoellipticae obtusae ad quartam partem liberae 3mm longae basi auriculatae. Pollinia erecta ovoidea. Discus stylinus pulvinatus. Folliculi ignoti.—Inflorescentia laxissima hanc speciem bene significat.

Ad Río Dolores, Cubilquitz, Depart. Alta Verapaz, Guat., alt. 350m, Aug. 1953, von Tuerckheim, n. 8558 ex Pl. Guat. etc., quas ed. Donn. Sm.

Ipomoea Tuerckheimii (Vatke ined.) Donn. Sm. ($STROPHIPOMOEA, Integrifoliae, Hastatae. Peter in Engl. et Prantl Nat. Pflanzenfam. IV. 3 30.)-Folia longe acuminato-cordiformia, lobis basalibus brevibus rotundatis, sinu acuto, margine subintegro vel sinuato-dentato. Pedunculi cymoso-pluriflori. Sepala aequalia dorso tuberculata. Corolla parva, limbo caeruleo.

Caulis cum petiolis et foliis novellis pubescens. Folia aetate provectiore praeter marginem glabrescentia 6-8cm longa 3.5-4.5cm lata mucrunculo apiculata usque ad quintam partem bilobata, petiolis 3.5-6cm longis. Pedunculi 2.5-3cm longi 2-7-flori. Sepala oblongo-ovata 4.5mm longa glabra, costa extus tuberculis rubris prominente. Corollae circa 2cm longae limbus fide cl. repertoris in vivo caeruleus. Capsula ovoidea 1cm longa breviter cuspidata bilocularis quadrivalvis, seminibus 4 vix puberulis.

Cobán, Depart. Alta Verapaz, Guat., alt. 1400m, Nov. 1886, von Tuerckheim, n. 386 ex Pl. Guat. etc., quas ed. Donn. Sm.-Cl. Hallier in Durand et Pitt. Prim. Fl. Cost. Fasc. III. 203 exemplum Tuerckheimianum sub nomine I. Tweediei Hoak. incaute ut videtur citavit.

Brachistus physocalycius Donn. Sm.-Folia dimorpha, altero lanceolato-oblongo alterum ovale multoties superante. Flores gemini. Calyx subinteger, fructifer valde auctus. Corolla infundibularis quarta parte lobata. Filamenta filiformia antheris longiora. Bacca calyce tota inclusa.

Fruticosus. Folia disticha membranacea supra glabra subtus cum ramis petiolisque pubescentia, majore 16-22 cm longo 5-6.5cm lato inaequilaterali sursum subsensim longeque acuminato basi inaequali plus minus acuto, petiolo 0.5-1.5cm longo, folio minore 1.5-6cm longo 1-3.5cm lato utrinque obtusiusculo, petiolo vix ullo. Pedunculi cernui 4-6mm longi. Flores toti glabri 12mm longi. Calyx campanulatus sub anthesi 3mm altus mucrunculo denticulatus. Corolla alba e basi paullatim ampliata, lobis ovatis erectis. Stamina 2mm supra basin corollae affixa, filamentis 3mm longis basi haud dilatatis, antheris oblongis 2mm longis. Stylus 9mm longus. Bacca globosa 7mm diametiens, seminibus complanatis suborbicularibus 2mm diametientibus in utroque loculo circiter 16.— B. oblongifolio Miers proximus differt insigniter calyce augescente Athenaeam simulante.

In silvis udis umbrosis ad Cubilquitz, Depart. Alta Verapaz, Guat., alt. 350, Oct. 1903, von Tuerckheim, n. 8553 ex Pl. Guat. etc., quas ed. Donn. Sm.

Columnea calotricha Donn. Sm. ($STYGNANTHE Benth. et Hook.) -Undique pilosa. Folia leviter disparia oblongo-elliptica utrinque acuta subintegra. Pedunculi petiolis breviores. Calycis segmenta sejuncta spathulato-oblonga. Corolla subclavato-tubulosa calyce 3-plo longior. Disci glandula unica.

Fruticulus saprogenus e basi repente ascendens in exemplis suppetentibus 5-16cm altus simplex caule petiolis foliis nascentibus floribus crinito-hirsutus, pilis articulatis rubro-tinctis. Folia subtus vinicoloria utrinque pilosa margine ciliata 5-8.5cm longa 2-3cm lata, petiolis 11-14mm longis, internodiis 5-15mm longis. Flores solitarii 40-42mm longi, pedunculis 6-8mm longis. Calycis segmenta subaequalia 13-15mm longa obtusa. Corolla rubiginosa recta e basi gibbosa paullatim leviterque ampliata faucibus haud constricta ore subobliqua, lobis 4mm longis inaequilatis. Bacca rubra ovalis 16mm longa.-C. moestae Poepp. et Endl. proxima differt autem inter alias notas glandula disci solitaria. Cubilquitz, Depart. Alta Verapaz, Guat., alt. 350m, Jul. 1903, von Tuerckheim, n. 8542 ex Pl. Guat. etc., quas ed. Donn. Sm.

Adenocalymna macrocarpum Donn. Sm. (§HANBURYOPHYTON Bur. et K. Sch.)-Glabrum. Folia conjugata, cirrho simplice vel plerumque deficiente, foliolis ellipticis vel oblongo-ellipticis apice subabrupte acuminatis basi acutis penninerviis subtus glandularipunctulatis. Thyrsi densiflori, rhachide pedunculum altero tanto excedente. Corolla anguste infundibularis. Stamina medium corollae vix attingentia. Capsula linearis perelongata, seminibus latissime alatis, nucleo tenui.

Frutex scandens, caule verrucoso ceterum glabro. Foliola 7-11cm longa 3.5-4.5cm lata coriacea supra sicco saturate viridia subtus pallidiora pallidius marginata basi complicata, nervis lateralibus utrinque circiter 5, petiolis 12-16mm longis, petiolulis 8-12mm longis utrinque incrassatis supra canaliculatis. Thyrsi axillares et terminales bracteis foliaceis 1.5-2 cm longis suffulti glabri, pedunculo 3-4cm longo, rhachide 6-8cm longa, ramis primariis oppositis 1.5-2 cm longis erecto-patentibus dichasia gerentibus, bracteolis linearibus minutis, pedicellis 0.5-1cm longis. Calyx eglandulosus pulverulentus campanulatus 6mm altus mucrunculis denticulatus. Corolla flava pulverulenta 6-6.5cm longa e tubo basilari cylindrico 7-8mm longo subsensim ampliata ad 6mm supra basin staminigera et ibidem pubescens, lobis inaequalibus 1-1.5cm longis. Stamina majora 21mm longa, minora 16mm longa, staminodio 5mm longo, antheris divaricatis nudis linearibus 3mm longis. Discus pulvinatus 2mm altus 3mm latus. Ovarium lineare teres 6mm longum puberulum, stylo 2.5cm longo, stigmatis lobis lanceolatis

3mm longis. Capsula generis adhuc longissima 29-52cm longa 1.5cm lata valde compressa eglandularis apice attenuata basi obtusa, valvis crasse coriaceis planis, nervo mediano percursis seminibus biseriatis pro loculo 20-25 alis hyalinis adjectis 4.5-5.5cm em latis 1.5cm altis, nucleo 1cm diametiente valde compresso.

Tecoluca, Depart. San Vincente, El Salvador, alt. 70m, Jan. 1893, Shannon, n. 5055 ex Pl. Guat. etc., quas ed. Donn. Sm.-Cubilquitz, Depart. Alta Verapaz, Guat., alt. 350m, ann. 1950, von Tuerckheim, n. 7759 ex Pl. Guat. etc., quas ed. Donn. Sm.-Eandem plantam in ditionibus Mexicanis collegit Pringle (n. 3898).— Haec exempla omnia sub Cydista aequinoctiali Miers, var. (Bignonia sarmentosa Bertol.), olim distributa sunt.

Cornutia cymosa Donn. Sm.-Ramuli teretes. Folia ampla ovalia vel suborbicularia utrinque rotundata. Cyma dichotoma corymbiformis latissima. Drupa generis adhuc maxima depresso-globosa, putamine osseo profunde exsculptato lacuna basali bifido.

Arbor, coma rotunda (Tonduz in schedula), ramulis petiolis cymae axibus pubescentibus vel glabrescentibus, gemmis ferrugineo-pilosis. Folia 14-27cm longa 13-20cm lata utrinque minute strigillosa siccitate bullata, costa nervisque validis, his utrinsecus 7-10 patulis sub margine junctis, venis transversis parallelis, venulis minute reticulatis, petiolis 2.5-4cm longis. Pedunculus 3-10cm longus, cyma sexies-decies dichotoma 10-14cm alta 16-23cm lata laxe floribunda, axibus robustis subangulatis, pedicellis 2-5mm longis. Calyx fructifer pubescens planiusculus 6-7mm latus, lobis ovatis. Drupa transversim leviter compressa 8-12mm longa 10-15mm lata, putamine sulcato et foveato a basi usque ad medium versus excavato abortu biloculari, seminibus lineari-oblongis. Flores ignoti.

In pascuis ad La Palma, Prov. San José, Costa Rica, alt. 1460m, Sept. 1898, Tonduz, n. 7383 ex Pl. Guat. etc., quas ed. Donn. Sm. (n. 12555 herb. nat. Cost.).

Trophis macrostachya Donn. Sm.-Folia maxima oblongoelliptica longe tenuiterque caudato-acuminata basi rotunda vel acuta supra medium repando-denticulata vel subintegra. Spicae masculinae dichotomae, femininae longissimae, perianthio fructifero sessili vel breviter pedicellato.

Arbor, ramulis novellis cum petiolis stipulis spicis pubescentibus. Folia coriacea supra glabra subtus nervis venisque pubescentia 15-22cm longa 6-9cm lată, acumine caudiformi 2-3cm longo, nervis lateralibus utrinsecus 12-14 juxta marginem junctis, petiolis 1-2cm longis, stipulis ovato-lanceolatis convolutis 5-6mm longis. Spicae masculinae bis furcatae continuatim densiflorae 5.5cm longae, perianthii segmentis imbricatis 2mm longis bracteolas et stamina aequantibus. Spicae femininae plerumque binae, floriferae 4-6cm longae, fructiferae 10-13cm longae, bracteolis rotundis 0.5mm longis ciliatis, perianthiis floriferis compactis, fructiferis laevibus pubescentibus ovalibus vel ovoideis 8-10mm longis, pedicellis interdum 1-3mm longis raro ramosis, fructu apice ipso tantum libero, semine 6mm longo.

In pascuis ad Las Vueltas, C. R., Nov. 1898, Tonduz, n. 8124 ex Pl. Guat. etc., quas ed. Donn. Sm. (n. 12802 herb. nat. Cost.).—In silvis ad Palmar, Costa Rica, Mart. 1892, Tonduz (n. 6751).-Tuís prope Turrialba, Prov. Cartago, Costa Rica, alt. 620, Jul. 1897, Pittier (n. 11266).—In silvis ad Tuís, Prov. Cartago, C. R., alt. 650m, Oct. 1897, Tonduz (n. 11357).

Sahagunia urophylla Donn. Sm.-Praeter perianthium glabra. Folia integra oblongo-elliptica vel late ovalia caudato-acuminata basi acutiuscula vel rotunda, nervis lateralibus utrinsecus 6-8. Pedunculi feminini solitarii aut gemini. Perianthium fructui pendulo infra apicem adnatum, pericarpio cartilagineo.

Folia subcoriacea supra saltem in sicco obscura subtus viridia, nunc 13-20cm longa in medio 5.5-8.5cm lata basi subacuta, nunc 6-8 cm longa 4-5cm lata basi rotunda, nervis venisque utrinque praesertim subtus manifestis, venulis grosse reticulatis, petiolis 1-1.5cm longis, stipulis lanceolatis 2-3mm longis caducis. Pedunculi feminini 3-4mm longi, fructibus 2-4 capitatis, additis floribus nascentibus nonnullis. Perianthium crasso-carnosum fusco-velutinum ovale 12mm longum collo subintegro apiculatum, fructu subgloboso 6-7mm diametiente, stylo 3mm longo, semine infra apicem affixo rufescente scrobiculoso. Flores utriusque sexus deficiunt.-Haec species generis tertia adhuc edita ab S. Mexicana Liebm. glabritie et foliis pro rata latioribus caudatis paucinerviis, ab S. strepitante Fr. Allem. foliis integris pedunculis saepe binis fructibus minoribus inter alia differt. In silvis prope Puerto Sierra, Honduras, Jan. 1903, Percy Wilson (n. 54). Coussapoa oligocephala Donn. Sm.-Folia oblongo- vel subovatoelliptica apice obtusiuscula et apiculata basi rotundata et emarginata discoloria supra glabra subtus arachnoidea. Cyma brevissime bis terve dichotoma, capitulis paucis subglabris. Stamen perianthio lobulato bis longius, anthera quadriloculari.

Frutex epiphyticus (fide oculatissimi repertoris supra Achras Sapota L. re vera parasiticus), ramulis novellis stipulis petiolis pedunculis cum cyma pilosis. Folia 10-16cm longa 4-7cm lata, nervis lateralibus utrinsecus 9-11 rectis in margine ipso terminatis, imis e basi extrorsum ramosis, petiolis 1.5-2.5cm longis. Pedunculi masculini solitarii vel gemini 2-2.5cm longi, capitulis 3-5 circa 4mm diametientibus, bracteolis tenuissime spatulatis. Perianthium turbinatum vix 1mm longum, lobulis brevibus rotundis incrassatis uti bracteolarum apex ad lentem puberulo-punctulatis. Capitula feminina non vidi.

Cubilquitz, Depart. Alta Verapaz, Guat., alt. 350m, Apr. 1904, von Tuerckheim, n. 8659 ex Pl. Guat. etc., quas ed. Donn. Sm.

BALTIMORE.

THE DEVELOPMENT OF ROOT HAIRS.

CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY.

LXXIV.

LAETITIA MORRIS SNOW.

(WITH PLATE I AND SIX FIGURES)

INTRODUCTION.

EXPERIMENTATION upon the effect of external agents on the development of root hairs is complicated by the fact that when external conditions are varied the internal factors are disturbed by an unknown amount. The varying of only one condition, which is the essential feature in accurate research, was thus extremely difficult, if not impossible. Therefore, the results to be set forth here are understood to be tentative. The last experimental work upon the immediate subject is that of SCHWARZ (75), to which the reader is referred for most of the earlier literature. Apart from three or four papers, the references to the causes for the development of root hairs are found incorporated, here and there, in reports on root studies, and as a rule are merely casual observations. The work here reported has been an endeavor to add some facts and suggestions as to the causes for the production of root hairs, variations in their structure not being considered.

LIGHT AND DARKNESS.

In view of the fact that in darkness there is generally an increase in the length of the axial organs and of their component cells (47, p. 64; 37, p. 254), and because authors differ as to the effect of light and darkness upon the development of root hairs, it seemed best to reinvestigate the matter. SCHWARZ (75, p. 163) reports no effect; WENT'S (85, p. 8) experiments were not very convincing one way or another; DEVAUX (10, p. 306) finds that light retards growth and favors the development of root hairs; PETHYBRIDGE (63a, p. 235) reports that light retards the production of hairs upon the roots of oats and wheat growing in water cultures. The last experiment was repeated several times, but very little difference was noted